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Graf, Holger; Stork, André

CAE/VR Integration - A Path to Follow? A Validation Based on Industrial Use

2017

Zoltay Paprika, Zita (Ed.) et al.: ECMS 2017 : 31st European Conference on Modelling and Simulation, pp. 436-445

European Conference on Modelling and Simulation (ECMS) <31, 2017, Budapest, Hungary>

Numerical simulations have become crucial during the product development process (PDP) for predicting and validating different properties of new products as well as the simulation of various kinds of natural phenomena. Especially the engineering domain (CAE - Computer Aided Engineering), is seeking for new ICT solutions to cover broad ranges of physical simulations. Virtual Reality (VR) has matured in the past allowing a rapid consolidation of information and decision-making through visualization and experience. These new man machine interfaces offer advanced interaction possibilities with the digital domain and allow engineers to variate over several hypothesis. This enlightened ideas to deploy VR for "what-if-scenarios" also in the CAE domain. However, while CAD/VR integration has been sufficiently researched, the integration of CAE into VR is still facing a long road ahead. Despite recent criticism that the application of VR technology has been considered unnecessary in CAE, this paper aims to refute this by presenting methodologies for linear static FEM analysis allowing "what-if-scenarios" within interactive environments. It validates the elaborated methodologies and advantages of VR front ends by an evaluation performed within industrial engineering departments.

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Mostajabodaveh, Seyedmorteza; Dietrich, Andreas; Gierlinger, Thomas; Michel, Frank; Stork, André

CSG Ray Tracing Revisited: Interactive Rendering of Massive Models Made of Non-planar Higher Order Primitives

2017

Cláudio, Ana Paula (Ed.) et al.: GRAPP 2017. Proceedings : 12th International Conference on Computer Graphics Theory and Applications (VISIGRAPP 2017 Volume 1). SciTePress, 2017, pp. 258-265

International Conference on Computer Graphics Theory and Applications (GRAPP) <12, 2017, Porto, Portugal>

In many scientific and engineering areas, CAD models are constructed by combining simple primitives using Boolean set operations. Rendering such a dataset usually requires a preprocess, where the surface of the CAD model is approximated by an often highly complex triangle mesh. Real-time ray tracing provides an alternative to triangle rasterization as it allows for the direct visualization of (higher-order) solid and planar primitives without having to triangulate them. Additionally, Boolean compositing operations can be performed implicitly per ray, primitives have low storage requirements, and curved surfaces appear pixel-accurate. In this paper we demonstrate these properties using massive real-world CAD models.

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Altenhofen, Christian; Schuwirth, Felix; Stork, André; Fellner, Dieter W.

Implicit Mesh Generation Using Volumetric Subdivision

2017

Jaillet, Fabrice (Ed.) et al.: VRIPHYS 17: 13th Workshop in Virtual Reality Interactions and Physical Simulations. Goslar: Eurographics Association, 2017, pp. 9-19

International Workshop in Virtual Reality Interaction and Physical Simulations (VRIPHYS) <13, 2017, Lyon, France>

In this paper, we present a novel approach for a tighter integration of 3D modeling and physically-based simulation. Instead of modeling 3D objects as surface models, we use a volumetric subdivision representation. Volumetric modeling operations allow designing 3D objects in similar ways as with surface-based modeling tools. Encoding the volumetric information already in the design mesh drastically simplifies and speeds up the mesh generation process for simulation. The transition between design, simulation and back to design is consistent and computationally cheap. Since the subdivision and mesh generation can be expressed as a precomputable matrix-vector multiplication, iteration times can be greatly reduced compared to common modeling and simulation setups. Therefore, this approach is especially well suited for early-stage modeling or optimization use cases, where many geometric changes are made in a short time and their physical effect on the model has to be evaluated frequently. To test our approach, we created, simulated and adapted several 3D models. Additionally, we measured and evaluated the timings for generating and applying the matrices for different subdivision levels. For comparison, we also measured the tetrahedral meshing functionality offered by CGAL for similar numbers of elements. For changing topology, our implicit meshing approach proves to be up to 70 times faster than creating the tetrahedral mesh only based on the outer surface. Without changing the topology and by precomputing the matrices, we achieve a speed-up of up to 2800.

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Altenhofen, Christian; Dietrich, Andreas; Stork, André; Fellner, Dieter W.

Rixels: Towards Secure Interactive 3D Graphics in Engineering Clouds

2017

Lukas, Uwe von (Ed.) et al.: Go-3D 2017: Mit 3D Richtung Maritim 4.0 : Tagungsband zur Konferenz Go-3D 2017. Stuttgart: Fraunhofer Verlag, 2017, pp. 25-43

Go-3D <8, 2017, Rostock, Germany>

Cloud computing rekindles old and imposes new challenges on remote visualization especially for interactive 3D graphics applications, e.g., in engineering and/or in entertainment. In this paper we present and discuss an approach entitled 'rich pixels' (short 'rixels') that balances the requirements concerning security and interactivity with the possibilities of hardware accelerated post-processing and rendering, both on the server side as well as on the client side using WebGL.

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Mueller-Roemer, Johannes; Altenhofen, Christian; Stork, André

Ternary Sparse Matrix Representation for Volumetric Mesh Subdivision and Processing on GPUs

2017

Computer Graphics Forum, Vol.36 (2017), 5, pp. 59-69

Eurographics Symposium on Geometry Processing (SGP) <15, 2017, London, UK>

In this paper, we present a novel volumetric mesh representation suited for parallel computing on modern GPU architectures. The data structure is based on a compact, ternary sparse matrix storage of boundary operators. Boundary operators correspond to the first-order top-down relations of k-faces to their (k-1)-face facets. The compact, ternary matrix storage format is based on compressed sparse row matrices with signed indices and allows for efficient parallel computation of indirect and bottomup relations. This representation is then used in the implementation of several parallel volumetric mesh algorithms including Laplacian smoothing and volumetric Catmull-Clark subdivision. We compare these algorithms with their counterparts based on OpenVolumeMesh and achieve speedups from 3x to 531x, for sufficiently large meshes, while reducing memory consumption by up to 36%.

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Luu, Thu Huong; Stork, André (Betreuer); Mueller-Roemer, Johannes (Betreuer)

Adaptives und hybrides SLAM für handgeführte RGBD-Kameras

2016

Darmstadt, TU, Master Thesis, 2016

Mit der steigenden Beliebtheit von RGBD-Sensoren wurde viel Forschung im Bereich der Aufnahme und Rekonstruktion von dreidimensionalen Umgebungen mit Hilfe von solchen Sensoren betrieben. Für die Konstruktion muss das sogenannte Simultaneous Localization and Mapping (SLAM)-Problem gelöst werden. Die meisten RGBD-SLAM-Systeme verwenden hierbei den punktbasierten Iterative Closest Point (ICP)-Algorithmus. Auch wenn ICP ein gut untersuchter Algorithmus ist, so stößt er bei verrauschten Daten und besonders bei texturarmen Bereichen mit wenigen geometrischen Merkmalen, wie z.B. großen leeren Flächen, auf Probleme. Eine Option, diese Limitierung anzugehen, ist das zusätzliche Ausnutzen von Ebenen in der Szene, besonders da sie die häufigste Form in von Menschen erbauten Innenräumen und Außenanlagen sind. Taguchi et al. [TJRF13] veröffentlichte 2013 die erste globale Registrierungsmethode, in welcher Punkt-zu-Punkt- und Ebene-zu-Ebene-Korrespondenzen zu einem echtzeitfähigen SLAM-System vereint werden. Kurz darauf folgte die Publikation von Ataer-Cansizoglu et al. [ACTRG13], welche zusätzlich ein Bewegungsvorhersage-Modell ausnutzt, um Korrespondenzen zu bestimmen. Ein Nachteil dieser Verfahren ist die hohe Verarbeitungszeit eines Registrierungsschrittes. Dieser bewirkt, dass die Verfahren nicht in der Lage sind, interaktive Rekonstruktionen durchzuführen. Das Ziel dieser Arbeit ist die Implementierung eines SLAM-Algorithmus für handgeführte RGBDKameras, der sowohl Punkte, als auch Flächen zur Registrierung nutzt. Im Gegensatz zu bestehenden Verfahren wird in dieser Arbeit ein lokaler Registrierungsalgorithmus umgesetzt. Flächenmerkmale werden bevorzugt verwendet, da ihre Anzahl in Szenen signifikant geringer ist als die von Punkten. Das ermöglicht eine schnellere Korrespondenzsuche und Registrierung. Dem zugrundeliegenden RANSACbasierten Algorithmus reicht bereits eine minimale Anzahl an Korrespondenzen aus, um die Sensorpose zu bestimmen. Somit ist der Algorithmus in der Lage, die Registrierung auch in texturarmen Bereichen mit wenigen geometrischen Merkmalen durchzuführen, in denen Techniken, welche nur Punkte benutzen, scheitern. Des Weiteren ermöglicht der lokale Registrierungsansatz eine interaktive Nutzung, um dem Nutzer in Echtzeit Rückmeldung über den Registrierungsprozess zu geben. Zusätzlich implementierte Erweiterungen, welche die detektierten Flächeninformationen zur Geometriekorrektur ausnutzen, unterstützen den Registrierungsvorgang. Durchgeführte Experimente demonstrieren eine interaktive Rekonstruktion von Innenräumen mit einer handgeführten RGBD-Kamera, einer Kinect. Zudem weist das System im Gegensatz zu vergleichbaren hybriden Systemen eine sechsfach höhere Rekonstruktionsrate auf. Bei der Gegenüberstellung anhand eines Benchmark-Datensatzes für RGBD-Sensoren konnte des Weiteren in texturarmen Umgebungen eine Überlegenheit gegenüber punktbasierten Verfahren nachgewiesen werden.

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Abramovici, Michael; Herzog, Otthein; Encarnação, José L.; Stork, André

Engineering im Umfeld von Industrie 4.0: Einschätzungen und Handlungsbedarf

2016

acatech, 2016

acatech STUDIE

Engineering im Zusammenhang mit Industrie 4.0 stellt eine gänzlich neue Herausforderung mit einer Vielzahl offener Fragen für alle Phasen des Produktlebenszyklus dar. Vernetzte smarte Produkte und Services eröffnen grundlegend neue Potenziale für Innovationen und neue Geschäftsfelder. Im Rahmen intensiver Gespräche mit Vertreterinnen und Vertretern aus der Wirtschaft wurden einige dieser Fragen und Innovationspotenziale adressiert und bewertet.

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Sevilmis, Neyir; Stork, André

Industrie 4.0: Cyber-physical Equivalence

2016

ProSTEP iViP Association: ProSTEP iViP Symposium 2016 : Smart Information Management for Product and Production. Darmstadt: ProSTEP, 2016, p. 68

ProSTEP iViP Symposium <2016, Stuttgart, Germany>

Our concept is called Cyber-physical Equivalence (CPE) and it contributes to the implementation of the Smart Factory.

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Königstein, Robert; Stork, André (Betreuer); Sevilmis, Neyir (Betreuer)

Optical Recognition of Transport Boxes for Logistics Applications

2016

Darmstadt, TU, Bachelor Thesis, 2016

This bachelor thesis will propose a novel approach for recognizing transport boxes on pallets in goods receipt in logistics. Especially if pallets are not labeled with barcodes or RFID-tags, it is very time consuming, to manually recognize and count the incoming boxes. Therefore, a measuring station, in which the pallets are recognized, is presented. Two images of opposite sides of the pallet are taken and further processed by a modular software to recognize and count the transport boxes. The process is divided into three main steps. In the first step, the input images are segmented to gain one image snippet for each transport box present in the image. This is done by morphologically transforming the input images and extracting the boundaries of the boxes. In a second step, each of the prior calculated image segments is classified by a multi-machine support vector machine, trained with histograms of visual words received by a Bag-of-Words model, in combination with colour information. Finally, the classification results of the images taken from two opposite perspectives of the pallet are merged to get an overall statement, of how many and which type of transport boxes are stacked on the pallet.

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Altenhofen, Christian; Dietrich, Andreas; Stork, André; Fellner, Dieter W.

Rixels: Towards Secure Interactive 3D Graphics in Engineering Clouds

2016

The IPSI BgD Transactions on Internet Research, Vol.12 (2016), 1, pp. 31-38

Cloud computing rekindles old and imposes new challenges on remote visualization especially for interactive 3D graphics applications, e.g., in engineering and/or in entertainment. In this paper we present and discuss an approach entitled 'rich pixels' (short 'rixels') that balances the requirements concerning security and interactivity with the possibilities of hardware accelerated post-processing and rendering, both on the server side as well as on the client side using WebGL.

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Weber, Daniel; Mueller-Roemer, Johannes; Stork, André; Fellner, Dieter W.

A Cut-Cell Geometric Multigrid Poisson Solver for Fluid Simulation

2015

Computer Graphics Forum, Vol.34 (2015), 2, pp. 481-491

Annual Conference of the European Association for Computer Graphics (Eurographics) <36, 2015, Zürich, Switzerland>

We present a novel multigrid scheme based on a cut-cell formulation on regular staggered grids which generates compatible systems of linear equations on all levels of the multigrid hierarchy. This geometrically motivated formulation is derived from a finite volume approach and exhibits an improved rate of convergence compared to previous methods. Existing fluid solvers with voxelized domains can directly benefit from this approach by only modifying the representation of the non-fluid domain. The necessary building blocks are fully parallelizable and can therefore benefit from multi- and many-core architectures.

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Müller, Joel; Stork, André (Betreuer); Altenhofen, Christian (Betreuer)

A Subdivision-Based Approach to the Heat Equation for Simulation-Based Modeling

2015

Darmstadt, TU, Bachelor Thesis, 2015

In this thesis a subdivision-based method is presented for calculating numerical solutions to differential equations on the basis of a geometric representation that is also well suited for modeling. While modern CAD programs mainly use continuous representations, like B-splines or NURBS, numerical methods like FEM require a discrete mesh to perform the calculation on. The conversion between these two representations can become a hugely time consuming process. Utilizing the same representation for modeling and simulating objects speeds up the whole engineering process, as the need for mesh generation is eliminated. This also reduces the error made by approximating the geometry. As subdivision schemes are intuitive and efficient to use for modeling and visualizing complex geometries, they serve well as a basis for this method. The presented method is based on Chaikin's algorithm for one-dimensional objects and utilizes Catmull-Clark surfaces to represent two-dimensional objects. On the basis of these two subdivision schemes, solutions to the heat equation are generated, demonstrating the applicability of the approach. The exactness of this solution and the performance of the algorithm are compared to a traditional FEM approach to the heat equation.

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Kadel, Simon; Stork, André (Betreuer); Borner, Matthias (Betreuer)

Automatische und geführte Anreicherung von Building Information Models mit Strukturelementen aus 3D-Punktwolken

2015

Darmstadt, TU, Bachelor Thesis, 2015

Digitale 3D-Modelle von Gebäuden, sogenannte Building Information Models, sind heute in der Gebäudeplanung allgegenwärtig. Um aus bereits bestehenden Gebäuden ein BIM zu gewinnen, wird in der Forschung nach Verfahren gesucht, die dies möglichst einfach machen. Momentan wird dabei meistens in zwei Abschnitten gearbeitet. Zuerst wird das Gebäude aufgenommen, anschließend wird die Aufnahme, zum Teil mit langwierigen oder manuellen Verfahren, analysiert. Falls dabei festgestellt wird, dass die Aufnahme für die Analyse nicht gut genug ist, besteht meist nicht oder nur unter erheblichem Mehraufwand die Möglichkeit, das Gebäude erneut aufzunehmen. Deshalb wird eine Möglichkeit benötigt, noch während der Aufnahme feststellen zu können, ob ein Model erstellt werden kann. Dazu müssen die verwendeten Verfahren robust sein und schnell arbeiten. In dieser Arbeit wird ein Objektanalyse genanntes Verfahren vorgestellt, das in Punktwolken Fenster und geöffnete Türen findet. Dieses Verfahren ist in eine ResourceApp genannte Anwendung eingebettet. Mit dieser können Räume aufgenommen werden, und in den bei der Aufnahme entstehenden Punktwolken Wände erkannt werden. Da die vorliegenden Punktwolken fehlerbehaftet und ungenau sein können, sind Verfahren aus anderen Arbeiten nicht einsetzbar. Den Ansatz für die Objektanalyse liefert aber ein Prinzip, das man in vielen Arbeiten findet: Die Punkte der Punktwolke werden aus dem 3D- in den 2D-Raum projiziert und können dort mit bewährten Methoden aus der Bildverarbeitung untersucht werden. Für die Projektion benutzt die Objektanalyse die Wandflächen des Raumes. Eine der Herausforderungen der Objektanalyse ist es, möglichst wenige Fehler zu machen. Dabei gibt es zwei Arten von Fehlern, false positive und false negative genannt. Das Verringern von einer Art führt meist zu einem Vermehren der anderen Art. Hier muss eine gute Abwägung getroffen werden. Die Objektanalyse arbeitet in mehreren Schritten. Im ersten Schritt werden die Punkte der Punktwolke auf die Wandebenen projiziert und dadurch für jede Wand ein Bild erstellt. Im zweiten Schritt werden in diesem Bild mit dem in [SA85] vorgestellten Algorithmus Konturen gesucht, die anschließend zur besseren Bearbeitung mit dem Ramer-Douglas-Peucker Algorithmus vereinfacht werden. Die gefundenen Konturen werden dann anhand von ihrer Form, ihrer Größe und ihrem Verhältnis zu anderen Konturen gefiltert, damit nur noch Konturen übrig bleiben, die für als Fenster oder Tür in Frage kommen. Dieser Schritt beeinflusst die Ergebnisse der Objektanalyse stark, was daran zu sehen ist, dass knapp 98% der Konturen ausgefiltert werden. Nach dem Filtern werden die Konturen anhand ihrer Lage, Form und Größe in Türen, Fenster und sonstige Objekte eingeteilt und abschließend wieder in den 3D-Raum zurückgerechnet und dem Modell als Objekte hinzugefügt. Die Objektanalyse wird von fünf Parametern gesteuert und kann damit für jeden Raum optimal angepasst werden. Da geschlossene Türen oder durch Jalousien verdeckte Fenster von der Objektanalyse nicht erkannt werden und um Fehler der Objektanalyse zu verbessern wird außerdem eine Erweiterung der Benutzeroberfläche der ResourceApp vorgestellt, die es ermöglicht, das Modell des Raumes nach der Objektanalyse zu bearbeiten. Diese bietet neben der 3D-Ansicht auch eine 2D-Ansicht, die aus den in der Objektanalyse entstandene Bildern der Wände besteht. Dadurch können Objekte bearbeitet, gelöscht und erzeugt werden. Neben Türen und Fenstern stehen hier auch weitere Objekte zur Verfügung, um das Modell des Raumes um diese zu erweitern. Außerdem wird die Möglichkeit geboten, die Wände des Raumes zu bearbeiten, falls diese nicht vorhanden oder ungenau sind. Die Objektanalyse kann dann auf diesen bearbeiteten Wänden durchgeführt werden. Getestet wurde die Objektanalyse anhand von sechs Räumen und auf zwei Rechnern. Die Ausführungszeit der Objektanalyse lag dabei immer unter einer halben Sekunde, im Schnitt sogar nur bei etwa 120 ms. Auch bei der Genauigkeit liefert die Objektanalyse gute Ergebnisse: Von den zehn gut aufgenommenen Objekten wurden 9 erkannt, und sogar eine schlecht aufgenommen Tür konnte erkannt werden. Zusammen mit der Möglichkeit zur manuellen Bearbeitung ist die Objektanalyse deshalb eine gute Lösung für die Problemstellung.

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Weber, Daniel; Mueller-Roemer, Johannes; Altenhofen, Christian; Stork, André; Fellner, Dieter W.

Deformation Simulation using Cubic Finite Elements and Efficient p-multigrid Methods

2015

Computers & Graphics, Vol.53 (2015), PART B, pp. 185-195

We present a novel p-multigrid method for efficient simulation of corotational elasticity with higher-order finite elements. In contrast to other multigrid methods proposed for volumetric deformation, the resolution hierarchy is realized by varying polynomial degrees on a tetrahedral mesh. The multigrid approach can be either used as a direct method or as a preconditioner for a conjugate gradient algorithm. We demonstrate the efficiency of our approach and compare it to commonly used direct sparse solvers and preconditioned conjugate gradient methods. As the polynomial representation is defined w.r.t. the same mesh, the update of the matrix hierarchy necessary for corotational elasticity can be computed efficiently. We introduce the use of cubic finite elements for volumetric deformation and investigate different combinations of polynomial degrees for the hierarchy. We analyze the applicability of cubic finite elements for deformation simulation by comparing analytical results in a static and dynamic scenario and demonstrate our algorithm in dynamic simulations with quadratic and cubic elements. Applying our method to quadratic and cubic finite elements results in a speed-up of up to a factor of 7 for solving the linear system.

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Schuwirth, Felix; Stork, André (Betreuer); Weber, Daniel (Betreuer)

Effiziente Simulation von Masse-Feder-Systemen

2015

Darmstadt, TU, Bachelor Thesis, 2015

In dieser Arbeit wird ein Zeitintegrationsverfahren vorgestellt, mit dem die Bewegungsgleichung eines Masse-Feder-Systems durch ein Optimierungsproblem gelöst werden kann. Das zur Lösung des Optimierungsproblems resultierende lineare Gleichungssystem (LGS) besitzt eine konstante Systemmatrix, die einmalig berechnet werden muss. Hierdurch ist in jedem Zeitschritt der Simulation lediglich eine Neuberechnung des Ergebnisvektors des LGS notwendig. Dieses lässt sich mit Hilfe des präkonditionertem konjugiertem Gradienten Verfahren lösen, deren höchster rechnerischer Aufwand in der Berechnung von dünn besetzten Matrix-Vektor- Multiplikationen (SpMV = Sparse Matrix Vector Multiplication) liegt. Daher wird eine spezielle GPU-Datenstruktur (GPU=Graphic Processor Unit) unter Verwendung regulärer Gitter entwickelt, um eine massiv parallele Berechnung der SpMV zu ermöglichen. Dadurch wird gegenüber anderer aktueller GPU-Implementierungen von SpMV eine deutlich höhere Anzahl von Rechenoperationen pro Sekunde erreicht. Weiterhin kann mit dieser speziellen Datenstruktur eine nahezu vollständige Ausnutzung der Speicherbandbreite der Grafikkarte realisiert werden. Diese Arbeit bietet damit einen guten Ansatz um eine effiziente Simulation von Masse-Feder-Systems zu realisieren.

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Encarnação, L. Miguel; Chuang, Yung-Yu; Stork, André; Kasik, Dave; Rhyne, Theresa-Marie; Avila, Lisa S.; Kohlhammer, Jörn; LaViola, Joseph J.; Tory, Melanie; Dill, John; Domik, Gitta; Owen, G. Scott; Wong, Pak Chung

Future Directions in Computer Graphics and Visualization: From CG&A's Editorial Board: Letter from the Editor

2015

IEEE Computer Graphics and Applications, Vol.35 (2015), 1, pp. 20-32

With many new members joining the CG&A editorial board over the past year, and with a renewed commitment to not only document the state of the art in computer graphics research and applications but to anticipate and where possible foster future areas of scientific discourse and industrial practice, CG&A asked its editorial and advisory council members about where they see their fields of expertise going. The answers compiled here aren't meant to be all encompassing or deterministic when it comes to the opportunities computer graphics and interactive visualization hold for the future. Instead, the goal is to give a more in-depth introduction of members of the editorial board to the CG&A readership and encourage cross-disciplinary discourse toward approaching, complementing, or disputing the visions laid out in this compilation. Here's what the CG&A editorial and advisory council members had to say.

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Weber, Daniel; Stork, André (Betreuer); Fellner, Dieter W. (Betreuer); Goesele, Michael (Betreuer)

Interactive Physically Based Simulation - Efficient Higher-Order Elements, Multigrid Approaches and Massively Parallel Data Structures

2015

Darmstadt, TU, Diss., 2015

This thesis covers interactive physically based simulation for applications such as computer games or virtual environments. Interactivity, i.e., the option that a user can influence a system, imposes challenging requirements on the simulation algorithms. A simple way to achieve this goal is to drastically limit the resolution in order to guarantee this low computation time. However, with current methods the number of degrees of freedom will be rather low, which results in a low degree of realism. This is due to the fact that not every detail that is important for realistically representing the physical system can be resolved. This thesis contributes to interactive physically based simulation by developing novel methods and data structures. These can be associated with the three pillars of this thesis: more accurate discrete representations, efficient methods for linear systems, and data structures and methods for massively parallel computing. The novel approaches are evaluated in two application areas relevant in computer generated animation: simulation of dynamic volumetric deformation and fluid dynamics. The resulting accelerations allow for a higher degree of realism because the number of elements or the resolution can be significantly increased.

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Lassmann, Andreas; Stork, André (Betreuer); Weber, Daniel (Betreuer)

Interaktive physikalisch-basierte Simulation auf verteilten Systemen

2015

Darmstadt, TU, Master Thesis, 2015

Diese Masterarbeit behandelt die interaktive physikalisch-basierte Simulation auf verteilten Systemen. Es wird untersucht, wie bestehende Algorithmen und Datenstrukturen für interaktive und nicht-interaktive Simulationen adaptiert werden müssen, um auf verteilten Systemen verwendet zu werden. Ein verteiltes System besteht aus mehreren Grafikkarten, die zusätzlich auf Rechenknoten im Netzwerk verteilt sein können. Als Algorithmen werden das Verfahren der konjugierten Gradienten und das Mehrgitterverfahren untersucht. Von Interesse ist die Skalierbarkeit mit Aussagen über die Laufzeit, Speedup und Effizienz im Zusammenhang mit der Anzahl an Freiheitsgraden.

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Windisch, Sebastian; Stork, André (Betreuer); Kuijper, Arjan (Betreuer)

Interaktive punktbasierte Visualisierung großer oberflächenbezogener Simulationsdaten

2015

Darmstadt, TU, Master Thesis, 2015

Die verteilte, rechnergestützte Simulation physikalischer Phänomene erzeugt abhängig von der Präzision der Simulation, des betrachteten Zeitintervalls und der Größe des Simulationsbereichs Ergebnisdatensätze, welche aufgrund ihres Datenvolumens schwer zu visualisieren und zu analysieren sind. Dies betrifft insbesondere die interaktive, explorative Analyse mittels konventioneller Arbeitsplatz-PCs, wie sie in Industrie und Forschung regelmäßig eingesetzt wird. Hierbei navigiert ein Benutzer interaktiv durch eine Visualisierung des Datensatzes um relevante Ergebnisse zu lokalisieren. Dies ist ein anwendungsspezifischer Vorgang um zum Beispiel unerwartete Daten zu finden oder solche, die eine Hypothese bestätigen oder widerlegen. Diese Resultatdaten sind häufig zu groß, um sie auf den PC zu übertragen und lokal zu verarbeiten. Limitierende Elemente in diesem Anwendungsszenario sind der lokale Haupt- und Grafikkartenspeicher, die lokale Rechenleistung, sowie die für die Datenübertragung zur Verfügung stehende Netzwerkbandbreite. Es existieren bereits verschiedene Ansätze, welche eine entfernte Visualisierung von großen dreiecksbasierten Modellen oder Szenen ermöglichen, jedoch setzen diese entweder eine langwierige Vorverarbeitung des ganzen Datensatzes voraus oder es besteht eine zu starke Bindung zwischen dem Client und den entfernten Ressourcen, sodass eine entkoppelte lokale Navigation oder lokale Anpassung von Visualisierungsparametern nicht möglich ist. In dieser Arbeit wird ein Ansatz basierend auf den Vorarbeiten von Get et al. [9] und Preiner et al. [17] vorgestellt, prototypisch implementiert und evaluiert. Dieser führt, gesteuert durch den Client, eine blickpunktabhängige punktbasierte Abtastung auf einem entfernten oberflächenbezogenen Simulationsdatensatz aus. Die daraus inkrementell gewonnene Punktwolke aus Simulationsdaten wird in einem Octree, der zwischen Client und Server synchronisiert wird, organisiert und temporär zwischengespeichert. Auf dem Client wird daraufhin mittels eines splatbasierten Rekonstruktionsverfahrens die Oberfläche des Simulationsdatensatzes wiederhergestellt. Mithilfe von Deferred Rendering und Color Mapping kann die Visualisierung der Simulationsdaten anschließend lokal modifiziert werden. Der Ansatz ermöglicht dabei eine Entkopplung der Datenkomplexität und der Renderleistung zwischen Client und Server. Anhand eines kleinen Beispieldatensatzes wird zum Schluss die Praktikabilität des Verfahrens experimentell evaluiert. Eine Evaluierung für große Daten konnte wegen fehlender Verfügbarkeit eines entsprechenden Datensatzes nicht durchgeführt werden. Die direkte Abhängigkeit der interaktiv visualisierbaren Datenmengen von den serverseitig verfügbaren Ressourcen kann jedoch aufgrund der Vorarbeiten von Ge et al. [9] angenommen werden.

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Berz, Florian; Stork, André (Betreuer); Altenhofen, Christian (Betreuer)

Intuitive 3D-Interaktion für Design und Modellierung von volumetrischen Strukturen

2015

Darmstadt, TU, Master Thesis, 2015

Creating an intuitive way of modeling and designing different structures is a task of high relevance with a wide range of applications in computer graphics. Various options will have to be considered with respect to new developments. For instance, the following options are addressed in this thesis: visualization and interaction. The availability of modern and low-cost 3D hardware provides the users with new possibilities. Visualization and interactions can be performed in 3D and new approaches to applying the interactions are required. In this regard, a combination of zSpace tablet and Leap Motion is proven to fulfill these requirements. Interactions with the mesh can be implemented with the zSpace tablet and Leap Motion is used to control the navigation in scene and menu. Overall, some relevant and new 3D interactions are developed which, amongst other things, allow for the manipulation of inner structures. Those 3D interactions are meaningful, useful and intuitive and therefore, this thesis contributes to the current developments.

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Rücker, Marko; Altenhofen, Christian (Betreuer); Stork, André (Betreuer)

Schnelle und wasserdichte Triangulierung von Punktwolken für die interaktive Simulation: Fast and Watertight Triangulation of Point Clouds for Interactive Simulation

2015

Darmstadt, TU, Bachelor Thesis, 2015

In der frühen Designphase eines realen Objektes (z.B. mittels Lehmmodell) ist eine schnelle Beurteilung darüber notwendig, ob das erstellte Objekt vorher definierten Anforderungen (z.B. Strömungs-, Stabilitätseigenschaften) gerecht wird. Es gibt traditionell zwei Ansätze: Einmal die Strömungsmessung in einem Windkanal oder die aufwendige manuelle Digitalisierung von Objekten mit einer anschließenden Simulation des virtuellen Modells. Diese Arbeit beschäftigt sich mit einigen Aspekten, die beiden Ansätze miteinander zu verbinden. Es sollen Vorteile der Modellierung an einem realen Objekt und der schnellen Beurteilung von Eigenschaften eines virtuellen Objekts durch Simulation verbunden werden. Dabei wird ein Ansatz gezeigt, bei dem die Triangulierung einer Punktewolke von ca. 68.000 Punkten weniger als zehn Sekunden benötigt. Weiterhin bietet dieser Ansatz eine qualitativ bessere Triangulierung bei gleichbleibender bzw. halber Rechenzeit mit vergleichbaren Algorithmen, die sich mit wasserdichten 2- mannigfaltigen Dreiecksnetzen beschäftigen.

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Stork, André

Visual Computing Challenges of Advanced Manufacturing and Industrie 4.0: Guest Editor's Introduction

2015

IEEE Computer Graphics and Applications, Vol.35 (2015), 2, pp. 21-25

Over the past few years, there has been a clear trend toward more individualized and customized products that require increasing flexibility in production. As a result of new manufacturing capabilities (such as 3D printing), socioeconomic trends, and the effects of the worldwide economic crisis in 2008/2009, the manufacturing industry recognized the need to make their production facilities as well as supply and logistic chains more flexible. Globally, this effort would also reinforce economies traditionally strong in engineering and manufacturing.

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Filippo, Francesco De; Stork, André; Schmedt, Hendrik; Bruno, Fabio

A Modular Architecture for a Driving Simulator Based on the FDMU Approach

2014

IJIDeM - International Journal on Interactive Design and Manufacturing, Vol.8 (2014), 2, pp. 139-150; First published online: 09 March 2013

The present paper describes the development of a modular and easily configurable simulation platform for ground vehicles. This platform should be usable for the implementation of driving simulators employed both in training purposes and in vehicle components testing. In particular, the paper presents a first architectural model for the implementation of a simulation platform based on the Functional Digital Mock-Up (FDMU) approach. This platform will allow engineers to implement different kinds of simulators that integrate both physical and virtual components, thus achieving the possibility to quickly reconfigure the architecture depending on the hardware and software used and on specific test case needs. The platform has been tested by developing a case study that integrates a motion platform, some I/O devices and a simple dynamic ground vehicle model implemented in OpenModelica.

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Weber, Daniel; Mueller-Roemer, Johannes; Altenhofen, Christian; Stork, André; Fellner, Dieter W.

A p-Multigrid Algorithm using Cubic Finite Elements for Efficient Deformation Simulation

2014

Bender, Jan (Ed.) et al.: VRIPHYS 14: 11th Workshop in Virtual Reality Interactions and Physical Simulations. Goslar: Eurographics Association, 2014, pp. 49-58

International Workshop in Virtual Reality Interaction and Physical Simulations (VRIPHYS) <11, 2014, Bremen, Germany>

We present a novel p-multigrid method for efficient simulation of co-rotational elasticity with higher-order finite elements. In contrast to other multigrid methods proposed for volumetric deformation, the resolution hierarchy is realized by varying polynomial degrees on a tetrahedral mesh. We demonstrate the efficiency of our approach and compare it to commonly used direct sparse solvers and preconditioned conjugate gradient methods. As the polynomial representation is defined w.r.t. the same mesh, the update of the matrix hierarchy necessary for co-rotational elasticity can be computed efficiently. We introduce the use of cubic finite elements for volumetric deformation and investigate different combinations of polynomial degrees for the hierarchy. We analyze the applicability of cubic finite elements for deformation simulation by comparing analytical results in a static scenario and demonstrate our algorithm in dynamic simulations with quadratic and cubic elements. Applying our method to quadratic and cubic finite elements results in speed up of up to a factor of 7 for solving the linear system.

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Hadjiprocopis, Andreas; Wenzel, Konrad; Rothermel, Mathias; Ioannides, Marinos; Fritsch, Dieter; Klein, Michael; Johnsons, Paul S.; Weinlinger, Guenther; Doulamis, Anastasios; Protopapadakis, Eftychios; Kyriakaki, Georgia; Makantasis, Kostas; Fellner, Dieter W.; Stork, André; Santos, Pedro

Cloud-based 3D Reconstruction of Cultural Heritage Monuments using Open Access Image Repositories

2014

Klein, Reinhard (Ed.) et al.: GCH 2014. Short Papers - Posters : Eurographics Workshop on Graphics and Cultural Heritage. Goslar: Eurographics Association, 2014, pp. 5-8

Eurographics Symposium on Graphics and Cultural Heritage (GCH) <12, 2014, Darmstadt, Germany>

A large number of photographs of cultural heritage items and monuments is publicly available in various Open Access Image Repositories (OAIR) and social media sites. Metadata inserted by camera, user and host site may help to determine the photograph content, geo-location and date of capture, thus allowing us, with relative success, to localise photos in space and time. Additionally, developments in Photogrammetry and Computer Vision, such as Structure from Motion (SfM), provide a simple and cost-effective method of generating relatively accurate camera orientations and sparse and dense 3D point clouds from 2D images. Our main goal is to provide a software tool able to run on desktop or cluster computers or as a back end of a cloud-based service, enabling historians, architects, archaeologists and the general public to search, download and reconstruct 3D point clouds of historical monuments from hundreds of images from the web in a cost-effective manner. The end products can be further enriched with metadata and published. This paper describes a workflow for searching and retrieving photographs of historical monuments from OAIR, such as Flickr and Picasa, and using them to build dense point clouds using SfM and dense image matching techniques. Computational efficiency is improved by a technique which reduces image matching time by using an image connectivity prior derived from low-resolution versions of the original images. Benchmarks for two large datasets showing the respective efficiency gains are presented.

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Lukas, Uwe von; Stork, André; Behr, Johannes

Industrie 4.0 - Evolution statt Revolution: Visual Computing beflügelt die Industrie der Zukunft

2014

wt Werkstattstechnik online, (2014), 4, pp. 255-257

Der Industrie stehen große Änderungen bevor: Künftig stimmen sich die Produktionsanlagen untereinander ab und steuern sich selbst, die Produkte wissen, wo sie sich befinden und was ihnen zum fertigen Artikel noch fehlt. Die Basis für diese Industrie der Zukunft wird am Fraunhofer IGD mithilfe des "Visual Computings" gelegt.

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Graf, Holger; Larson, Mats; Stork, André

Interactive 3D Subdomaining using Adaptive FEM based on Solutions to the Dual Problem

2014

Proceedings of the 2014 Virtual Reality International Conference : VRIC 2014. New York: ACM Press, 2014, 8 p.

Virtual Reality International Conference (VRIC) <16, 2014, Laval, France>

This paper presents a new technique for automatic, interactive 3D subdomaining coupled to mesh and simulation refinements in order to enhance local resolutions of CAE domains. Numerical simulations have become crucial during the product development process (PDP) for predicting different properties of new products as well as the simulation of various kinds of natural phenomena. "What-if-scenarios" and conceptual changes to either the boundary or the domain are time consuming and cost intensive. Most of the time, engineers are interested in a deeper understanding of local quantities rather than being exposed to an iterative re-simulation of the overall domain. New techniques for automatic and interactive processes are then challenged by the cardinality and structural complexity of the CAE domain. This paper introduces a new interactive technique that automatically reduces the analysis space, and allows engineers to enhance the resolution of local problems without a need for recalculating the global problem. The technique, integrated into a VR based front end, achieves faster reanalysis cycles compared with traditional COTS tool chains and engineering workflows.

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Santos, Pedro; Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

The Potential of 3D Internet in the Cultural Heritage Domain

2014

Ioannides, Marinos (Ed.) et al.: 3D Research Challenges in Cultural Heritage : A Roadmap in Digital Heritage Preservation. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8355), pp. 1-17

Europe is rich in cultural heritage but unfortunately much of the tens of millions of artifacts remain in archives. Many of these resources have been collected to preserve our history and to understand their historical context. Nevertheless, CH institutions are neither able to document all the collected resources nor to exhibit them. Additionally, many of these CH resources are unique, and will be on public display only occasionally. Hence, access to and engagement with this kind of cultural resources is important for European culture and the legacy of future generations. However, the technology needed to economically mass digitize and annotate 3D artifacts in analogy to the digitization and annotation of books and paintings has yet to be developed. Likewise approaches to semantic enrichment and storage of 3D models along with meta-data are just emerging. This paper presents challenges and trends to overcome the latter issues and demonstrates latest developments for annotation of 3D artifacts and their subsequent export to Europeana, the European digital library, for integrated, interactive 3D visualization within regular web browsers taking advantage of technologies such as WebGl and X3D.

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Doulamis, Anastasios; Ioannides, Marinos; Doulamis, Nikolaos; Hadjiprocopis, Andreas; Fritsch, Dieter; Balet, Olivier; Julien, Martine; Protopapadakis, Eftychios; Makantasis, Kostas; Weinlinger, Guenther; Johnsons, Paul S.; Klein, Michael; Fellner, Dieter W.; Stork, André; Santos, Pedro

4D Reconstruction of the Past

2013

Hadjimitsis, Diofantos G. (Ed.) et al.: First International Conference on Remote Sensing and Geoinformation of the Environment : RSCy 2013. Bellingham: SPIE Press, 2013. (Proceedings of SPIE 8795), pp. 87950J-1 - 87950J-11

International Conference on Remote Sensing and Geoinformation of the Environment (RSCy) <1, 2013, Paphos, Cyprus>

One of the main characteristics of the Internet era we are living in, is the free and online availability of a huge amount of data. This data is of varied reliability and accuracy and exists in various forms and formats. Often, it is cross-referenced and linked to other data, forming a nexus of text, images, animation and audio enabled by hypertext and, recently, by the Web3.0 standard. Search engines can search text for keywords using algorithms of varied intelligence and with limited success. Searching images is a much more complex and computationally intensive task but some initial steps have already been made in this direction, mainly in face recognition. This paper aims to describe our proposed pipeline for integrating data available on Internet repositories and social media, such as photographs, animation and text to produce 3D models of archaeological monuments as well as enriching multimedia of cultural / archaeological interest with metadata and harvesting the end products to EUROPEANA. Our main goal is to enable historians, architects, archaeologists, urban planners and affiliated professionals to reconstruct views of historical monuments from thousands of images floating around the web.

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Weber, Daniel; Bender, Jan; Schnös, Markus; Stork, André; Fellner, Dieter W.

Efficient GPU Data Structures and Methods to Solve Sparse Linear Systems in Dynamics Applications

2013

Computer Graphics Forum, Vol.32 (2013), 1, pp. 16-26

We present graphics processing unit (GPU) data structures and algorithms to efficiently solve sparse linear systems that are typically required in simulations of multi-body systems and deformable bodies. Thereby, we introduce an efficient sparse matrix data structure that can handle arbitrary sparsity patterns and outperforms current state-of-the-art implementations for sparse matrix vector multiplication. Moreover, an efficient method to construct global matrices on the GPU is presented where hundreds of thousands of individual element contributions are assembled in a few milliseconds. A finite-element-based method for the simulation of deformable solids as well as an impulse-based method for rigid bodies are introduced in order to demonstrate the advantages of the novel data structures and algorithms. These applications share the characteristic that a major computational effort consists of building and solving systems of linear equations in every time step. Our solving method results in a speed-up factor of up to 13 in comparison to other GPU methods.

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Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Embodiment Discrete Processing

2013

Abramovici, Michael (Ed.) et al.: Smart Product Engineering : Proceedings of the 23rd CIRP Design Conference. Berlin, Heidelberg, New York: Springer, 2013. (Lecture Notes in Production Engineering (LNPE)), pp. 421-429

International CIRP Design Conference <23, 2013, Bochum, Germany>

The phases of the embodiment stage are sequentially conceived and in some domains even cyclic conceived. Nevertheless, there is no seamless integration between these, causing longer development processes, increment of time lags, loss of inertia, greater misunderstandings, and conflicts. Embodiment Discrete Processing enables the seamless integration of three building blocks. 1) Dynamic Discrete Representation: it is capable to concurrently handle the design and the analysis phases. 2) Dynamic Discrete Design: it deals with the needed modeling operations while keeping the consistency of the discrete shape. 3) Dynamic Discrete Analysis: it efficiently maps the dynamic changes of the shape within the design phase, while streamlining the interpretation processes. These integrated building blocks support the multidisciplinary work between designers and analysts, which was previously unusual. It creates a new understanding of what an integral processing is, whose phases were regarded as independent. Finally, it renders new opportunities toward a general purpose processing.

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Woidasky, Jörg; Stier, Christian; Stork, André; Sevilmis, Neyir; Schultmann, Frank; Stengel, Julian

Erkennung und Erschließung von Rohstoffpotentialen aus dem Hochbau

2013

Rüppel, Uwe (Ed.): 2. Darmstädter Ingenieurkongress : Bau und Umwelt. Tagungsband. Aachen: Shaker Verlag, 2013. (Berichte aus dem Bauwesen), pp. 669-673

Darmstädter Ingenieurkongress <2, 2013, Darmstadt, Germany)

Durch die Kombination von 3D-Rekonstruktion, Bilderkennung und Semantischen Technologien soll für ressourceneffiziente Rückbau- und Abbruchmaßnahmen eine gebäudescharfe, aktuelle, kurzfristig verfügbare und vor allem verlässliche Datenbasis bereitgestellt werden, auf der wirksame Verwertungsstrategien für Wertstoffe aus dem Baubereich aufsetzen. Dies ist insbesondere für Bereiche äußerst relevant, für die derzeit keine Schätzwerte (z. B. Stahl aus Nichtwohngebäuden) oder nur große Schätz-Intervalle (z. B. Kupfer im Gebäudebestand) existieren.

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Limper, Max; Wagner, Stefan; Stein, Christian; Jung, Yvonne; Stork, André

Fast Delivery of 3D Web Content: A Case Study

2013

Posada, Jorge (General Chair) et al.: Proceedings Web3D 2013 : 18th International Conference on 3D Web Technology. New York: ACM Press, 2013, pp. 11-17

International Conference on 3D Web Technology (WEB3D) <18, 2013, San Sebastian, Spain>

Despite many advances in mesh compression methods within the past two decades, there is still no consensus about a standardized compact mesh encoding format for 3D Web applications. In order to facilitate the design of a future platform-independent solution, this paper investigates the crucial trade-off between compactness of the compressed representation and decompression time. Our case study evaluates different encoding formats, combined with various transmission bandwidths, using different client devices. Results indicate that good compression rates, and at the same time a fast decompression, can be achieved by exploiting existing browser features and by minimizing the complexity of operations that have to be performed inside the JavaScript layer. Our findings are summarized in concrete recommendations for future standards.

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Graf, Holger; Stork, André

Virtual Reality Based Interactive Conceptual Simulations: Combining Post-processing and Linear Static Simulations

2013

Shumaker, Randall (Ed.): Virtual Augmented and Mixed Reality. Designing and Developing Augmented and Virtual Environments. Proceedings Part I : VAMR 2013. Berlin, Heidelberg, New York: Springer, 2013. (Lecture Notes in Computer Science (LNCS) 8021), pp. 13-22

International Conference Virtual Augmented and Mixed Reality (VAMR) <5, 2013, Las Vegas, NV, USA>

This paper presents a new approach for the design and realization of a Virtual Reality (VR) based engineering front end that enables engineers to combine post processing tasks and finite element methods for linear static analyses at interactive rates. "What-if-scenarios" have become a widespread methodology in the CAE domain. Here, designers and engineers interact with the virtual mock-up, change boundary conditions (BC), variate geometry or BCs and simulate and analyze its impact on the CAE mock-up. The potential of VR for post-processing engineering data enlightened ideas to deploy it for interactive investigations at conceptual stage. While it is a valid hypothesis, still many challenges and problems remain due to the nature of the "change'n play" paradigm imposed by conceptual simulations as well as the non-availability of accurate, interactive FEM procedures. Interactive conceptual simulations (ICS) require new FEM approaches in order to expose the benefit of VR based front ends.

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Lukas, Uwe von; Stork, André

Visual Computing für die nächste industrielle Revolution

2013

Economic Engineering: Intelligente Methoden, Prozesse und Technologien, (2013), 4, pp. 36-38

Anhand konkreter Beispiele zeigen die Autoren vom Fraunhofer IGD Forschungsbedarf im Themenfeld Visualisierung auf. Die Konzepte von Industrie 4.0 bieten enorme Innovationspotenziale für die Produktion, beeinflussen aber letztlich den kompletten Produktlebenszyklus vom Entwurf bis zum Retrofit. Nach unserer umfassenden Interpretation des Begriffs "Industrie 4.0" lassen sich diese Potenziale nur durch den Einsatz von Technologien des Visual Computing tatsächlich umsetzen.

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Stork, André; Fellner, Dieter W.

3D-COFORM - Tools and Expertise for 3D Collection Formation

2012

Bienert, Andreas (Ed.) et al.: EVA 2012 Berlin. Proceedings : Elektronische Medien & Kunst, Kultur, Historie. Berlin: Gesellschaft zur Förderung angewandter Informatik e.V., 2012, pp. 35-49

Electronic Imaging & the Visual Arts (EVA) <19, 2012, Berlin, Germany>

3D-COFORM has the overall aim to make 3D documentation the standard approach in cultural heritage institutions for collection formation and management. 3D-COFORM is addressing the whole life cycle of digital 3D objects (also called 3D documents) spanning the whole chain from acquisition to processing, and from semantic enrichment to modeling and high-quality presentation - all that on the basis of an integrated repository infrastructure. The paper will give an overview of 3D-COFORM and present its current results and contributions.

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Bein, Matthias; Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Completing Digital Cultural Heritage Objects by Sketching Subdivision Surfaces toward Restoration Planning

2012

Ioannides, Marinos (Ed.) et al.: Progress in Cultural Heritage Preservation : 4th International Conference, EuroMed 2012. Berlin, Heidelberg, New York: Springer, 2012. (Lecture Notes in Computer Science (LNCS) 7616), pp. 301-309

International Euro-Mediterranean Conference on Cultural Heritage and Digital Libraries (EuroMed) <4, 2012, Limassol, Cyprus>

In the restoration planning process a curator evaluates the condition of a Cultural Heritage (CH) object and accordingly develops a set of hypotheses for improving it. This iterative process is complex, time consuming and requires many manual interventions. In this context, we propose interactive modeling techniques, based on subdivision surfaces, which can support the completion of CH objects toward restoration planning. The proposed technique starts with a scanned and incomplete object, represented by a triangle mesh, from which a subdivision surfaces can be generated. Based on the mixed representation, sketching techniques and modeling operations can be combined to extend and refine the subdivision surface, according to the curator's hypothesis. Thus, curators without rigorous modeling experience can directly create and manipulate surfaces in a similar way as they would do it on a piece of paper. We present the capabilities of the proposed technique on two interesting CH objects.

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Stork, André; Sevilmis, Neyir; Weber, Daniel; Gorecky, Dominic; Stahl, Christian; Loskyll, Matthias; Michel, Frank

Enabling Virtual Assembly Training in and beyond the Automotive Industry

2012

International Society on Virtual Systems and MultiMedia: Proceedings of the VSMM 2012 : Virtual Systems in the Information Society. Los Alamitos, Calif.: IEEE Computer Society, 2012, pp. 347-352

International Conference on Virtual Systems and MultiMedia (VSMM) <18, 2012, Milan, Italy>

Virtual assembly training systems show a high potential to complement or even replace physical setups for training of assembly processes in and beyond the automotive industry. The precondition for the breakthrough of virtual training is that it overcomes the problems of former approaches. The paper presents the design approach taken during the development of a game-based, virtual training system for procedural assembly knowledge in the EU-FP7 project VISTRA. One key challenge to address when developing virtual assembly training is the extensive authoring effort for setting up virtual environments. Although knowledge from the product and manufacturing design is available and could be used for virtual training, a concept for integration of this data is still missing. This paper presents the design of a platform which transfers available enterprise data into a unified model for virtual training and thus enables virtual training of workers at the assembly line before the physical prototypes exist. The data requirements and constraints stemming from industrial partners involved in the project will be discussed. A second hurdle for virtual training is the insufficient user integration and acceptance. In this context, the paper introduces an innovative hardware set-up for game-based user interaction, which has been chosen to enhance user involvement and acceptance of virtual training

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Grasser, Tim; Stork, André (Betreuer); Weber, Daniel (Betreuer)

Energy-Preserving Integrators for Fluid Animation with Discrete Exterior Calculus on Two-Dimensional Meshes

2012

Darmstadt, TU, Bachelor Thesis, 2012

In the last decades a lot of approaches have been developed for implementing computational fluid dynamics (CFD) in the computer graphics community. One of the new approaches in fluid simulations is the discrete exterior calculus (DEC). DEC uses well-centered meshes to describe its integration space. Mullen et al. [MCP+09] introduced 2009 a new integration scheme based on DEC and the Navier-Stokes equations that preserves mass by definition of DEC. His discrete formulation of the Navier-Stokes equations provides full control about viscosity and moreover an almost perfect preservation of kinetic energy. We translate Mullens discretization into two dimensions and extend it to regular girds. We will discuss how to manage non-trivial boundary conditions. Finally we will analyze the results of Mullens approach, and analyze alternative methods to further improve those results.

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Ritz, Martin; Langguth, Fabian; Scholz, Manuel; Goesele, Michael; Stork, André

High Resolution Acquisition of Detailed Surfaces with Lens-Shifted Structured Light

2012

Computers & Graphics, Vol.36 (2012), 1, pp. 16-27. First published 29 October 2011 as Article in Press

We present a novel 3D geometry acquisition technique at high resolution based on structured light reconstruction with a low-cost projector-camera system. Using a 1D mechanical lens-shifter extension in the projector light path, the projected pattern is shifted in subpixel scale steps with a granularity of up to 2048 steps per projected pixel, which opens up novel possibilities in depth accuracy and smoothness for the acquired geometry. Combining the mechanical lens-shifter extension with a multiple phase shifting technique yields a measuring range of 120×80 mm while at the same time providing a high depth resolution of better than 100µm. Reaching beyond depth resolutions achieved by conventional structured light scanning approaches with projector-camera systems, depth layering effects inherent to conventional techniques are fully avoided. Relying on low-cost consumer products only, we reach an area resolution of down to 55µm (limited by the camera). We see two main benefits. First, our acquisition setup can reconstruct finest details of small cultural heritage objects such as antique coins and thus digitally preserve them in appropriate precision. Second, our accurate height fields are a viable input to physically based rendering in combination with measured material BRDFs to reproduce compelling spatially varying, material-specific effects.

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Peña Serna, Sebastian; Schmedt, Hendrik; Ritz, Martin; Stork, André

Interactive Semantic Enrichment of 3D Cultural Heritage Collections

2012

Arnold, David (Ed.) et al.: VAST 2012 : Eurographics Symposium Proceedings. Goslar: Eurographics Association, 2012, pp. 33-40

International Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST) <13, 2012, Brighton, UK>

Virtual Surrogates of Cultural Heritage (CH) objects are seriously being considered in professional activities such as conservation and preservation, exhibition planning, packing, and scholarly research, among many other activities. Although this is a very positive development, a bare 3D digital representation is insufficient and poor for fulfilling the full range of professional activities. In this paper, we present the first interactive semantic enrichment tool for 3D CH collections that is fully based on the CIDOC-CRM schema and that fully supports its sophisticated annotation model. The tool eases the user interaction, allowing inexperienced users without previous knowledge on semantic models or 3D modeling to employ it and to conceive it for the professional workflow on 3D annotations. We illustrate the capabilities of our tool in the context of the Saalburg fort, during Roman times (2nd century AD), for the protection of the Limes on the Taunus hills in Germany.

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Weber, Daniel; Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Rapid CFD für die frühe konzeptionelle Design Phase

2012

NAFEMS Online Magazin, Vol.21 (2012), 1, pp. 70-79

Ein wichtiger Teil des Produktentwicklungszyklus ist die Optimierung der strömungs- oder strukturmechanischen Eigenschaften einer Komponente, die normalerweise in einem iterativen und sehr aufwändigen Prozess stattfindet. Neben der Modifikation, Vereinfachung und des Vernetzens der Bauteilgeometrie, kann die Simulation mitunter Stunden bis Tage dauern. In frühen konzeptionellen Designphasen müssen verschiedene Materialparameter sowie unterschiedliche Geometrien ausprobiert und verglichen werden, um zu einem für das spätere Produkt optimalen Design zu gelangen. Dieser zeitaufwändige Prozess begrenzt deutlich die Anzahl der Möglichkeiten, die analysiert werden können. In dieser Arbeit wird das Framework "Rapid CFD" vorgestellt, das es ermöglicht, schnelle Strömungssimulationen für die frühe konzeptionelle Designphase einzusetzen. Um eine solche Geschwindigkeit zu erreichen, wird die Berechnung und Visualisierung von zweidimensionalen Strömungen in Echtzeit kombiniert. Das ermöglicht die interaktive Modifikation von Parametern und Randbedingungen und damit eine schnelle Analyse und Bewertung von unterschiedlichen Geometrien und eine frühzeitige Optimierung eines Bauteils. Das Framework führt alle Berechnungen auf der Graphikkarte (graphics processing unit - GPU) aus und vermeidet damit das aufwändige Kopieren zwischen CPU- und GPU-Hauptspeicher. Die Berechnungen werden auf einem Standard-Desktop PC ausgeführt, sodass die Simulationsergebnisse im Graphikkartenspeicher bleiben und direkt zur Visualisierung verwendet werden können. Für die Modellierung der Geometrie werden B-Splines verwendet, damit Benutzer lokal die Form durch einzelne Kontrollpunkte modifizieren können. Die Diskretisierung wird ebenfalls auf der GPU ausgeführt. Die Berechnung eines einzelnen Zeitschritts auch für Millionen von Unbekannten wird in Bruchteilen von Sekunden durchgeführt. Die intuitive geometrische Manipulation in Kombination mit der unmittelbaren Visualisierung der Simulationsgrößen wie Druck und Geschwindigkeit ermöglichen die direkte Analyse des Einflusses von Geometrie- und Parameteränderungen. Obwohl diese neuartige Simulationstechnik noch nicht die hohe Präzision konventioneller Simulationen erreicht, ermöglicht diese Technik die Beobachtung von Trends und Tendenzen.

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Ackermann, Jens; Ritz, Martin; Stork, André; Goesele, Michael

Removing the Example from Example-based Photometric Stereo

2012

Kutulakos, Kiriakos N. (Ed.): Trends and Topics in Computer Vision : ECCV 2010 Workshops, Revised Selected Papers, Part II. Berlin, Heidelberg, New York: Springer, 2012. (Lecture Notes in Computer Science (LNCS) 6554), pp. 197-210

Reconstruction and Modeling of Large-Scale 3D Virtual Environments (RMLE) <2010, Heraklion, Greece>

We introduce an example-based photometric stereo approach that does not require explicit reference objects. Instead, we use a robust multi-view stereo technique to create a partial reconstruction of the scene which serves as sceneintrinsic reference geometry. Similar to the standard approach, we then transfer normals from reconstructed to unreconstructed regions based on robust photometric matching. In contrast to traditional reference objects, the scene-intrinsic reference geometry is neither noise free nor does it necessarily contain all possible normal directions for given materials.We therefore propose several modifications that allow us to reconstruct high quality normal maps. During integration, we combine both normal and positional information yielding high quality reconstructions. We show results on several datasets including an example based on data solely collected from the Internet.

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Weber, Daniel; Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Schnelle Strömungsberechnungen mit GPU: Rapid CFD für die frühe konzeptionelle Designphase

2012

Digital Engineering Magazin, Vol.15 (2012), 5, pp. 44-47

Eine neue Tragfläche entsteht am Computer. Ist ihr Auftrieb tatsächlich besser als bei den herkömmlichen? Eine Computersimulation kann hierüber Aufschluss geben. Konventionelle Simulationen liefern die gewünschten Ergebnisse gewöhnlich erst nach mehreren Stunden oder Tagen. Erst anschließend können Modifikationen an der Geometrie vorgenommen werden, um die Eigenschaften zu verbessern. Ein neues Verfahren liefert nun die ersten Simulationsergebnisse bereits in Echtzeit. Es nutzt die Prozessoren der Grafikkarten (Graphics Processing Unit- GPU) für die notwendigen Berechnungen.

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Rodriguez Echavarria, Karina; Theodoridou, Maria; Georgis, Christos; Arnold, David; Doerr, Martin; Stork, André; Peña Serna, Sebastian

Semantically Rich 3D Documentation for the Preservation of Tangible Heritage

2012

Arnold, David (Ed.) et al.: VAST 2012 : Eurographics Symposium Proceedings. Goslar: Eurographics Association, 2012, pp. 41-48

International Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST) <13, 2012, Brighton, UK>

Traditionally, 3D acquisition technologies have been used to record heritage artefacts and to support specific tasks such as conservation or provenance verification. These exercises are usually a one-off as the technology and resources required are cost intensive. However, there is a recent impetus on the creation of 3D collections to document heritage artefacts which are semantically enriched by using annotations. A requirement of these solutions is the ability to support several representations of a heritage artefact recorded through time. This paper will propose an infrastructure to systematically enrich 3D shapes in a collection by using propagated annotations. In addition, it will describe the mechanisms for annotating, propagating and structuring the annotations using the CIDOC-CRM ontology. The results of this research have the potential to support heritage organisations in making their semantically rich 3D content available to a wider audience of professionals.

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Arnold, David; Kaminski, Jaime; Niccolucci, Franco; Stork, André

VAST 2012. Short and Project Papers

2012

Goslar : Eurographics Association, 2012

International Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST) <13, 2012, Brighton, UK>

The VAST conference not only focuses on the development of innovative solutions, but it will investigate the issues of the exploitation of computer science research by the cultural heritage community. The transition from research to practical reality can be fraught with difficulty. The digital environment provides new opportunities and new business processes for sustainability, but with these opportunities there are also challenges. VAST 2012 will provide an opportunity for the heritage and ICT communities to understand these challenges and shape the future of ICT and heritage research. This year the short and project papers will be complimented by their own dedicated panel discussions.

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Arnold, David; Niccolucci, Franco; Stork, André; Kaminski, Jaime

VAST 2012: Eurographics Symposium Proceedings

2012

Goslar : Eurographics Association, 2012

International Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST) <13, 2012, Brighton, UK>

VAST is a primary event, enabling on the one hand the interaction between Archaeologists, Cultural Heritage professionals and Information and Communication Technology (ICT) scientists, and on the other hand the dissemination of innovative solutions for the preservation and conservation of the world heritage. VAST is a unique scenario for the demonstration of state of the art research in the areas of data acquisition and processing, metadata handling, and presentation, as well as for the communication and understanding of practitioners' experience in the field. The VAST platform boosts the establishment of 3D documentation and digital libraries as standard instruments for the integration of 3D digital assets within professional environments, fostering the scholarly research and the public engagement.

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Peña Serna, Sebastian; Scopigno, Roberto; Doerr, Martin; Theodoridou, Maria; Georgis, Christos; Ponchio, Federico; Stork, André

3D-Centered Media Linking and Semantic Enrichment Through Integrated Searching, Browsing, Viewing and Annotating

2011

Dellepiane, Matteo (Ed.) et al.: VAST 2011 : Eurographics Symposium Proceedings. Goslar: Eurographics Association, 2011, pp. 89-96

International Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST) <12, 2011, Prato, Italy>

The digitally documented world heritage is archived in databases or repositories, where collections of metadata, images, multimedia objects or nowadays even digital 3D artifacts can be stored and queried. Modeling and linking all this information is complex and involves refined categorizations and relations, which are usually accessed by either simplistic or overwhelmingly complex interfaces. Hence, finding the right level of abstraction for a general interface is very challenging. This becomes even more demanding, if in addition to collection exploration, semantic enrichment is required. This work focuses on the design and implementation of an integrated interface, in which four dedicated activities are combined and provided: i) flexible definition of relational queries, ii) browsing of multiple results and query refinement, iii) inspection and analysis of multimedia objects, and iv) building and enrichment of semantic relationships (data paths) between objects. This integrated interface can handle different kinds of multimedia objects, allowing for querying and annotating text, 2D images or 3D artifacts. We present the software design of this interface and the corresponding underlying model in the semantic network. This work is a general step toward interfacing to 3D Linked Open Data.

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Huff, Rafael; Gierlinger, Thomas; Kuijper, Arjan; Stork, André; Fellner, Dieter W.

A Comparison of xPU Platforms Exemplified with Ray Tracing Algorithms

2011

IEEE Computer Society: XIII Symposium on Virtual Reality : SVR 2011. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2011, pp. 1-8

Symposium on Virtual Reality (SVR) <13, 2011, Uberlandia, Brazil>

Over the years, faster hardware - with higher clock rates - has been the usual way to improve computing times in computer graphics. Aside from highly costly parallel solutions only affordable by big industries - like the movie industry -, there was no alternative available to desktop users. Nevertheless, this scenario is dramatically changing with the introduction of more and more parallelism in current desktop PCs. Multi-core CPUs are a common basis in current PCs and the power of modern GPUs - which have been multi-core for a long time now - is getting unveiled to developers. nVidia's CUDA is a powerful weapon to explore GPUs parallelism. Yet, its specific target - nVidia graphic cards only - does not provide any solution to other parallel hardware present. OpenCL is a new royalty-free cross-platform intended to be portable across different hardware manufacturers or even different platforms. In this paper we focus on a comparison of advantages and disadvantages of xPU platforms with OpenCL and CUDA in terms of time efficiency. As an example application we use ray tracing algorithms. Three kinds of ray tracers have to be developed in order to conduct a fair comparison: one is CPU based, while the other two are GPU based - using CUDA and OpenCL, respectively. At the end, a comparison is done between them and results are presented and analyzed showing that the CUDA implementation has the best frame rate, but is very closely followed by the OpenCL implementation. Visually, results are identical, showing the high potential of OpenCL as an alternative for CUDA with identical performance.

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Stork, André; Bein, Matthias

Adaption von Verfahren der Geometrieanalyse aus industriellen Anwendungen auf das Problem der Bestimmung von 3D-Wasser-Land-Grenzen

2011

Bundesanstalt für Gewässerkunde (BfG): Zeitgemäße Erfassung und Bereitstellung von Geobasisdaten für die WSV. Koblenz: Druckerei Fuck, 2011. (Veranstaltungen der Bundesanstalt für Gewässerkunde 3/2011), pp. 101-109

Kolloquium "Zeitgemäße Erfassung und Bereitstellung von Geobasisdaten für die WSV" <2011, Koblenz, Germany>

Das dem vorliegenden Beitrag zugrundeliegende Projekt untersucht, inwieweit sich Ansätze der Geometrieanalyse aus industriellen Anwendungen auf das Problem der Definition von Wasser-Land-Grenzen adaptieren lassen. Ein Ziel dabei ist die Minimierung von Benutzerinterventionen. Als erweiterte Lösungsidee liegt unserem Ansatz eine Kombination aus Geometrieanalyse und der Einbeziehung zusätzlicher Informationen aus Geobasisdaten, namentlich der vektoriellen Beschreibung von Verläufen von Wasserstraßen in ATKIS-Daten, zugrunde.

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Binotto, Alecio; Pereira, Carlos Eduardo; Kuijper, Arjan; Stork, André; Fellner, Dieter W.

An Effective Dynamic Scheduling Runtime and Tuning System for Heterogeneous Multi and Many-Core Desktop Platforms

2011

Thulasiraman, Parimala (Ed.) et al.: Proceedings 2011 IEEE International Conference on High Performance Computing and Communications : HPCC 2011. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2011, pp. 78-85

IEEE International Conference on High Performance Computing and Communications (HPCC) <13, 2011, Banff, Alberta, Canada>

A personal computer can be considered as a one-node heterogeneous cluster that simultaneously processes several application tasks. It can be composed by, for example, asymmetric CPU and GPUs. This way, a high-performance heterogeneous platform is built on a desktop for data intensive engineering calculations. In our perspective, a workload distribution over the Processing Units (PUs) plays a key role in such systems. This issue presents challenges since the cost of a task at a PU is non-deterministic and can be affected by parameters not known a priori. This paper presents a context-aware runtime and tuning system based on a compromise between reducing the execution time of engineering applications - due to appropriate dynamic scheduling - and the cost of computing such scheduling applied on a platform composed of CPU and GPUs. Results obtained in experimental case studies are encouraging and a performance gain of 21.77% was achieved in comparison to the static assignment of all tasks to the GPU.

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Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Considerations toward a Dynamic Mesh Data Structure

2011

Larsson, Thomas (Ed.) et al.: SIGRAD 2011 : Evaluations of Graphics and Visualization - Efficiency, Usefullness, Accesibility, Usability. Linköping: Linköping University Electronic Press, 2011. (Linköping Electronic Conference Proceedings 65), pp. 83-90

SIGRAD Conference <10, 2011, Stockholm, Sweden>

The use of 3D shapes in different domains such as in engineering, entertainment, cultural heritage or medicine, is essential for representing 3D physical reality. Regardless of whether the 3D shapes are representing physically or digitally born objects, meshes are a versatile and common representation for the 3D reality. Nonetheless, the mesh generation process does not always produce qualitative results, thus incomplete, non-orientable or non-manifold meshes frequently are the input for the domain application. The domain application itself also demands special requirements, e.g. an engineering simulation requires a volumetric mesh either tetrahedral or hexahedral, while a cultural heritage color enhancement uses a triangular or quadrangular mesh, or in both cases even hybrid meshes. Moreover, the processes applied on the meshes (e.g. modeling, simulation, visualization) need to support some operations, such as querying neighboring information or enabling dynamic changes of geometry and topology. These operations need to be robust, hence the neighboring information can be consistently updated, during the dynamic changes. Dealing with this mesh diversity usually requires dedicated data structures for performing in the given domain application. This paper compiles the considerations toward designing a data structure for dynamic meshes in a generic and robust manner, despite the type and the quality of the input mesh. These aspects enable a flexible representation of 3D shapes toward general purpose geometry processing for dynamic meshes in 2D and 3D.

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Gandhe, Adwait; Stork, André (Betreuer); Ritz, Martin (Betreuer); Schmedt, Hendrik (Betreuer)

Dense 3D Reconstruction and Object Recognition using a Minimum Set of Inside-Out Images

2011

Pilani, BITS Univ., Bachelor Thesis, 2011

Dense 3D Reconstruction of environments is important for various applications like augmented reality, artefact digitization and object classification. Object classification in particular allows for scene understanding. This work proposes the development of a pipeline for image based 3D reconstruction and object recognition. The 2D images under consideration are the inside out images of the interior of a room. A dense 3D reconstruction allows the description of the room as point clouds on which the object recognition algorithms are implemented. To allow for flexibility in terms of image acquisition methods, the algorithm is robust to the type of image input as well as the number of images. Matching algorithms like Scale Invariant Feature Transform (SIFT) provide accurate correspondences while Structure from Motion (SFM) algorithms use these correspondences to estimate precise camera pose and Multi-view Stereo (MVS) methods take images with pose as input and produce dense 3D models. The reconstructed scenes are then acted upon by the 3D feature extractor and the features are compared with pre-trained classifiers from a database to carry out object recognition. The pipeline has been developed to allow for different types of Multi-view Stereo input images. While plane images allow for cheap equipment, spherical and cylindrical panoramic images allow for ease in image acquisition. We have used a modified version of the existent Open Street Map (OSM) Bundler for Structure from Motion and an overlapping view clustering problem for the Multi-view Stereo. Iterative Closest Point algorithm allows for integrating the depth maps to generate the mesh model. The pipeline also allows for an input generated using the Microsoft Xbox Kinect. We have used the Cluster Viewpoint Feature Histogram algorithm (CVFH) for the object recognition and also proposed the use of Normal Aligned Radial Features (NARF). We also study the prospect of using 2D to 3D feature correlation to find objects in the 3D generated model of the room from a 2D image of that room. This work also shows the results of a comparative study undertaken between the different possible methods to complete the task. We also study the different image geometries to further explore the invariance to camera models. Finally the pipeline has been integrated in the Rapid Prototyping Environment (RPE) framework of the Department Interactive Engineering Technologies as a plug-in to provide additional functionality.

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Wagner, Mathias; Schneider, Peter; Hinnerichs, Andreas; Bruder, Thomas; Stork, André

FunctionalDMU: Co-Simulation of Mechatronic Systems in a Virtual Environment

2011

The American Society of Mechanical Engineers (ASME): ASME 2011 World Conference on Innovative Virtual Reality : WINVR 2011. New York: The American Society of Mechanical Engineers, 2011, 6 p.

ASME World Conference on Innovative Virtual Reality (WINVR) <3, 2011, Milan, Italy>

Digital Mock-Up (DMU) is a widely introduced technology to virtually investigate geometrical and mechanical product properties. Functional Digital Mock-Up (FunctionalDMU) is a combination of traditional DMU with behavioral simulation in mechatronics. Enhancing DMU with functional aspects, considerably more insight in product properties can be gained. To enable FunctionalDMU two main tasks have to be solved: a) simulators in the areas of mechanics, electronics, and software simulation have to talk to each other (coupling) and b) the simulation results have to be visualized in an interactive DMU environment. In this paper we present an independent and open approach to a FunctionalDMU framework including co-simulation. Starting with proprietary and natively given behavior and geometric models (in formats like JT), we wrap the behavior models into SysML to enable data exchange on an agreed and standardized format. The native behavior models still are executed in the corresponding simulators. The simulators are linked to the FunctionalDMU framework using a wrapping approach. Currently we support simulators such as Matlab/Simulink, Dymola, Saber, Rhapsody, SimPack, ANSYS with our framework. During simulation a simulator coupling algorithm controls the simulation processes. A dedicated visualization environment enables the user to interact with the simulation, i.e., to send simulation stimuli, change parameters, observe the simulation run etc. This paper introduces the components of the FunctionalDMU framework and illustrates the approach with an application example.

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Bein, Matthias; Fellner, Dieter W.; Stork, André

Genetic B-Spline Approximation on Combined B-Reps

2011

The Visual Computer, Vol.27 (2011), 6-8, pp. 485-494

Computer Graphics International (CGI) <29, 2011, Ottawa, Canada>

We present a genetic algorithm for approximating densely sampled curves with uniform cubic B-Splines suitable for Combined B-reps. A feature of this representation is altering the continuity property of the B-Spline at any knot, allowing combining freeform curves and polygonal parts within one representation. Naturally there is a trade-off between different approximation properties like accuracy and the number of control points needed. Our algorithm creates very accurate B-Splines with few control points, as shown in Fig. 1. Since the approximation problem is highly nonlinear, we approach it with genetic methods, leading to better results compared to classical gradient based methods. Parallelization and adapted evolution strategies are used to create results very fast.

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Weber, Daniel; Kalbe, Thomas; Stork, André; Fellner, Dieter W.; Goesele, Michael

Interactive Deformable Models with Quadratic Bases in Bernstein-Bézier-Form

2011

The Visual Computer, Vol.27 (2011), 6-8, pp. 473-483

Computer Graphics International (CGI) <29, 2011, Ottawa, Canada>

We present a physically based interactive simulation technique for de formable objects. Our method models the geometry as well as the displacements using quadratic basis functions in Bernstein-Bézier form on a tetrahedral finite element mesh. The Bernstein-Bézier formulation yields significant advantages compared to approaches using the monomial form. The implementation is simplified, as spatial derivatives and integrals of the displacement field are obtained analytically avoiding the need for numerical evaluations of the elements' stiffness matrices. We introduce a novel traversal accounting for adjacency in order to accelerate the reconstruction of the global matrices. We show that our proposed method can compensate the additional effort introduced by the co-rotational formulation to a large extent. We validate our approach on several models and demonstrate new levels of accuracy and performance in comparison to current state-of-the-art.

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Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Interactive Exploration of Design Variations

2011

International Association for the Engineering Analysis Community (NAFEMS): A World of Engineering Simulation: Industrial Needs, Best Practice, Visions for the Future : NWC 2011. NAFEMS World Congress [Book of Abstracts & CD-ROM]. Glasgow: NAFEMS, 2011, 18 p.

International Congress on Simulation Technology for the Engineering Analysis Community (NWC) <13, 2011, Boston, USA>

The digital exploration of design variations is a key procedure in the embodiment phase of engineering design, in order to efficiently develop optimal solutions. This procedure requires the combination of modeling and simulation capabilities, enabling the engineer to assess the physical and functional behaviors of the proposed solution. Nowadays, this procedure is performed by means of iterating between designers and analysts with their corresponding tools and demanding reciprocal understanding between them. This is nonetheless a very time consuming activity with the currently available tools and technology, even the advance Computer Aided Design (CAD) systems, which can cope with almost any modeling requirement and which presently provide direct connection (i.e. meshing) to analysis modules for models with limited complexity, cannot deal with the interactive exploration of design variations. Moreover, the promising isogeometric analysis, which aims to simulate 3D NURBS representations also requires special transformations (i.e. meshing), which do not allow for interactive exploration of design variations. On the other side, the Computer Aided Engineering (CAE) systems offering morphing support, are only able to explore restricted variations, since large variations or deformations of the model involves expensive remeshing processes. In order to overcome the above mentioned issues and to enable a fully interactive exploration of design variations within an analysis environment, we enhance the simulating model with a high level representation for interacting with semantic features rather than with single elements, we perform combined morphing techniques with local mesh modification for preserving the stability of the numerical model during large variations, and we decouple the storage of the linear system entries and the sequential matrixvector multiplication for getting the solution, in order to permit the update of local entries of the matrix representing the local mesh modifications without the need of a rebuild of the entire system. Our methodology allows the engineers to independently and interactively explore conceptual design variations without restrictions. Hence, the investigation and understanding of the influence of different design features can easily and fast be evaluated and the development of optimal solutions for the design requirements can closely be fulfilled.

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Graf, Holger; Stork, André

Linear Static, Real-Time Finite Element Computations based on Element Masks

2011

The American Society of Mechanical Engineers (ASME): ASME 2011 World Conference on Innovative Virtual Reality : WINVR 2011. New York: The American Society of Mechanical Engineers, 2011, 9 p.

ASME World Conference on Innovative Virtual Reality (WINVR) <3, 2011, Milan, Italy>

This paper presents a new method for the manipulation of a given CAE domain in view of VR based explorations that enables engineers to interactively inspect and analyze a linear static domain. The interactions can ideally be performed in real-time in order to provide an intuitive impression of the changes to the underlying volumetric domain. We take the approach of element masking, i.e. the blending out of computations resulting from computational overhead for inner nodes, based on the inversion of the stiffness matrix. This allows us to optimize the re-simulation loop and to achieve real-time performance for strain and stress distributions with immediate visualization feedback caused by interactively changing boundary conditions. The novelty of the presented approach is a direct coupling of view dependent simulations and its close linkage to post-processing tasks. This allows engineers to also inspect the changes of the stress field inside of the volume during, e.g. cross sectioning.

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Santos, Pedro; Schmedt, Hendrik; Amend, Bernd; Hammer, Philip; Giera, Ronny; Hergenröther, Elke; Stork, André

LIS3D: Low-Cost 6DOF Laser Interaction for Outdoor Mixed Reality

2011

Shumaker, Randall (Ed.): Virtual and Mixed Reality - New Trends: Part I : International Conference, Virtual and Mixed Reality 2011. Berlin, Heidelberg, New York: Springer, 2011. (Lecture Notes in Computer Science (LNCS) 6773), pp. 270-279

International Conference on Virtual and Mixed Reality (VMR) <4, 2011, Orlando, FL, USA>

This paper introduces a new low-cost, laser-based 6DOF interaction technology for outdoor mixed reality applications. It can be used in a variety of outdoor mixed reality scenarios for making 3D annotations or correctly placing 3D virtual content anywhere in the real world. In addition, it can also be used with virtual back-projection displays for scene navigation purposes. Applications can range from design review in the architecture domain to cultural heritage experiences on location. Previous laser-based interaction techniques only yielded 2D or 3D intersection coordinates of the laser beam with a real world object. The main contribution of our solution is that we are able to reconstruct the full pose of an area targeted by our laser device in relation to the user. In practice, this means that our device can be used to navigate any scene in 6DOF. Moreover, we can place any virtual object or any 3D annotation anywhere in a scene, so it correctly matches the user's perspective.

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Weber, Daniel; Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Rapid CFD for the Early Conceptual Design Phase

2011

International Association for the Engineering Analysis Community (NAFEMS): The Integration of CFD into the Product Development Process : Seminar. Glasgow: NAFEMS, 2011, 9 p.

Seminar the Integration of CFD into the Product Development Process <2011, Wiesbaden, Germany>

An important step of the product development is the optimization of the components' physical behavior, which is usually done in a costly iterative process. Besides the modification, simplification, and (re-) meshing of the component's geometry, simulating its behavior can take hours or even days. In the early conceptual design phase, different material properties and shapes need to be tested and compared, in order to optimally design the component. Nonetheless, time consuming simulations limit the realm of possibilities. We have developed a framework for enabling rapid Computational Fluid Dynamics (CFD) for the early conceptual design phase. In order to achieve this, we combine the computation and visualization of 2D fluid flow in real time with the modification of fluid parameters, boundary conditions and geometry. This allows for the rapid assessment and analysis of different shapes and therefore the optimization of the component. Our framework is completely based on graphic processing units (GPUs), i.e., all computations are performed on the GPU avoiding costly memory transfers between graphic hardware and CPU memory. The computations are performed on a single desktop PC, thus the simulation results can reside in GPU memory and can directly be visualized. B-Spline curves are used for modelling the geometry and the user can interactively modify it by means of inserting and moving control points or applying local smooth deformations, with the corresponding rapid update of the discretization on the GPU. Computing one single time step is performed in fractions of a second, even if the fluid flow is modelled with about one million degrees of freedom. The fast geometric manipulation combined with the direct visualization of quantities like velocity or pressure field allows for an immediate feedback of shape or parameter changes. Although fast simulations do not yet achieve the high precision compared to conventional simulations, their results are suitable for analyzing trends.

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Müller, Constantin; Stork, André (Betreuer); Weber, Daniel (Betreuer)

Splines auf Tetraederpartitionen für physikalisch basierte Deformationssimulation

2011

Darmstadt, TU, Bachelor Thesis, 2011

Bei der Simulation von elastischen Deformationen mit Hilfe der Finiten-Elemente-Methode gibt es zwei Möglichkeiten die Genauigkeit der Approximation zu verbessern. Zum Einen die Erhöhung der Anzahl der Elemente, zum Anderen die Erhöhung des Polynomgrades der Basisfunktionen. Durch die Erhöhung des Polynomgrades steigt die Anzahl der Freiheitsgrade, was wiederum zu längeren Berechnungszeiten führt. Beschrieben wird die elastische Deformation von Körpern durch Partielle Differentialgleichungen (PDGLn) mit glatten Lösungen. Dies ermöglicht die Approximation der PDGLn mit den Basisfunktionen von Splines, die weniger Freiheitsgrade benötigen, da sie wegen ihrer Stetigkeitseigenschaften per Definition glatte Funktionen beschreiben. Die Simulation deformierbarer Materialien mit Splinefunktionen wird vorgestellt und die dadurch erreichte Genauigkeit und Performanz wird ermittelt und im Vergleich zur Finiten-Elemente-Methode diskutiert.

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Wendt, Lars Henning; Stork, André; Kuijper, Arjan; Fellner, Dieter W.

3D Reconstruction from Line Drawings

2010

Institute for Systems and Technologies of Information, Control and Communication (INSTICC): VISIGRAPP 2010. Proceedings : International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications. INSTICC Press, 2010, pp. 65-71

International Conference on Computer Graphics Theory and Applications (GRAPP) <5, 2010, Angers, France>

In this work we introduce an approach for reconstructing digital 3D models from multiple perspective line drawings. One major goal is to keep the required user interaction simple and at a minimum, while making no constraints to the objects shape. Such a system provides a useful extension for digitalization of paper-based styling concepts, which today is still a time consuming process. In the presented method the line drawings are first decomposed in curves assembling a network of curves. In a second step, the positions for the endpoints of the curves are determined in 3D, using multiple sketches and a virtual camera model given by the user. Then the shapes of the 3D curves between the reconstructed 3D endpoints are inferred. This leads to a network of 3D curves, which can be used for first visual evaluations in 3D. During the whole process only little user interaction is needed, which only takes place in the pre- and post-processing phases. The approach has been applied on multiple sketches and it is shown that the approach creates plausible results within reasonable timing.

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Santos, Pedro; Gierlinger, Thomas; Huff, Rafael; Ritz, Martin; Stork, André

A Full HDR Pipeline from Acquisition to Projection

2010

ACM SIGGRAPH: Siggraph 2010. Full Conference DVD-ROM. New York: ACM Press, 2010. (Computer Graphics Annual Conference Series), 1 p.

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH) <37, 2010, Los Angeles, CA, USA>

In this publication we present one of the first full HDR visualization systems starting with HDR material and light acquisition, providing a HDR light simulation and rendering pipeline and finally displaying maximum fidelity image quality with color gamut enhanced HDR projection technology to bring the total dynamic range to over 5.000.000:1. We demonstrate these capabilities in the fields of car design and architecture.

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Huff, Rafael; Neves, Tiago; Gierlinger, Thomas; Kuijper, Arjan; Stork, André; Fellner, Dieter W.

A General Two-Level Acceleration Structure for Interactive Ray Tracing on the GPU

2010

Computer Graphics Society (CGS): Computer Graphics International 2010. Short Papers : CGI [online]. [cited 01 February 2011] Available from: http://cgi2010.miralab.unige.ch/CGI_ShortPapersD4.html, 2010, 4 p.

Computer Graphics International (CGI) <28, 2010, Singapore>

Despite the superior image quality generated by ray tracing, programmers of time-critical applications have historically avoided it because of its computational costs. Nowadays, the hardware of modern desktops allows the execution of realtime ray tracers but requires a specialized implementation based on specific characteristics of each application, such as scene complexity, kinds of motion, ray distribution, model structure and hardware. The evaluation and development of these requirements are complex and time-consuming, especially for developers with no familiarity in rendering algorithms and graphics hardware programming. The aim of our work is to provide a general and practical method to efficiently execute interactive ray tracing in most systems. We considered the most common aspects of current computer graphics applications, like the use of a scene graph and support to static and dynamic objects. In addition, we also took into account the common desktop hardware. This led us to the development of a special acceleration structure and its implementation on the GPU. In this paper, we present the development of our work showing the combination of different techniques and our results.

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Santos, Pedro; Stork, André; Buaes, Alexandre; Pereira, Carlos Eduardo; Jorge, Joaquim

A Real-time Low-cost Marker-based Multiple Camera Tracking Solution for Virtual Reality Applications

2010

Journal of Real-Time Image Processing, Vol.5 (2010), 2, pp. 121-128. First published as Online First, 11 November 2009, DOI 10.1007/s11554-009-0138-9

One of the reasons of how virtual reality applications penetrate industrial production chains slowly is because of significant investment costs to purchase adequate supporting hardware. As a consequence such applications are only available to major companies and fail to benefit the production processes of small and medium enterprises. In this article, we introduce PTrack, a real-time, low-cost, marker-based multiple camera tracking solution for virtual reality providing the accuracy and scalability usually found in much more expensive tracking systems. PTrack is composed of single camera tracking PTrack Units. Each unit is connected to a video camera equipped with infrared strobes and features a novel iterative geometric pose estimation algorithm which does marker-based single camera tracking and is therefore completely autonomous. Multiple PTrack units successively extend the tracking range of the system. For a smooth transition of tracked labels from one camera to another, camera range areas must overlap to form a contiguous tracking space. A PTrack Sensor Fusion Module then computes the pose of a certain label within tracking space and forwards it to interested applications. A universal test setup for optical tracking systems has been built allowing to measure translational and rotational accuracy of PTrack as well as of competing systems.

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Graf, Holger; Santos, Pedro; Stork, André

Augmented Reality Framework Supporting Conceptual Urban Planning and Enhancing the Awareness for Environmental Impact

2010

Khan, Azam (Ed.): 2010 Proceedings of the Symposium on Simulation for Architecture and Urban Design, pp. 119-128

Symposium on Simulation for Architecture and Urban Design (SimAUD) <1, 2010, Orlando, FL, USA>

This paper introduces a new augmented reality framework based on a multi-source urban planning backbone aiming at interactively investigating fast "what-if" analysis of urban planning simulations and creating awareness of possible environmental impact. The process of advanced urban planning nowadays includes the simulation of physical phenomena, its analysis, visualization and interpretation in order to evaluate the impact on the layout of the planning. For example, noise and air pollution, annoyances due to both nearby transportation infrastructure and urban traffic have become a serious concern for citizens. In order to provide major aid to the involved stakeholders, especially city managers, new techniques for the preparation, representation and interpretation of the typically large amount of resulting simulation data are required. These must be designed in order to enhance the perceptual and cognitive processes of users to facilitate faster interpretation and decision making. Hence, we introduce a new augmented reality framework which not only allows users to visualize but also to analyze physical phenomena in fast "what-if"- scenarios. By changing boundary conditions, parameters and re-simulating at interactive rates results can be augmented into real world planning layouts. Augmenting reality, urban planning and layouts with resulting simulation data through real-time visualizing tools provides a new and efficient interactive post processing unit for the exploration and analysis of the environmental impact due to changing conditions.

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Binotto, Alecio; Pedras, Bernardo; Götz, Marcelo; Kuijper, Arjan; Pereira, Carlos Eduardo; Stork, André; Fellner, Dieter W.

Effective Dynamic Scheduling on Heterogeneous Multi/Manycore Desktop Platforms

2010

Bentes, Cristiana (Ed.) et al.: SBAC-PADW 2010 : 1st Workshop on Applications for Multi and Many Core Architectures (WAMMCA). Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2010, pp. 37-42

Workshop on Applications for Multi and Many Core Architectures (WAMMCA) <1, 2010, Petrópolis, Brazil>

GPUs (Graphics Processing Units) have become one of the main co-processors that contributed to desktops towards high performance computing. Together with multicore CPUs and other co-processors, a powerful heterogeneous execution platform is built on a desktop for data intensive calculations. In our perspective, we see the modern desktop as a heterogeneous cluster that can deal with several applications' tasks at the same time. To improve application performance and explore such heterogeneity, a distribution of workload over the asymmetric PUs (Processing Units) plays an important role for the system. However, this problem faces challenges since the cost of a task at a PU is non-deterministic and can be influenced by several parameters not known a priori, like the problem size domain. We present a context-aware architecture that maximizes application performance on such platforms. This approach combines a model for a first scheduling based on an offline performance benchmark with a runtime model that keeps track of tasks' real performance. We carried a demonstration using a CPU-GPU platform for computing iterative SLEs (Systems of Linear Equations) solvers using the number of unknowns as the main parameter for assignment decision. We achieved a gain of 38.3% in comparison to the static assignment of all tasks to the GPU (which is done by current programming models, such as OpenCL and CUDA for Nvidia).

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Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Embodiment Mesh Processing

2010

Fischer, Xavier (Ed.) et al.: Research in Interactive Design. Volume 3 : Virtual, Interactive and Integrated Product Design and Manufacturing for Industrial Innovation. Paris, Berlin, Heidelberg: Springer, 2010, 6 p.

International Conference on Integrated, Interactive and Virtual Product Engineering (IDMME - Virtual Concept) <2010, Boreaux, France>

During the last two decades, several approaches have been proposed, in order to deal with the integration in the embodiment phase of the engineering design. This phase deals with the virtual product development and it is supported by Computer-Aided Design (CAD) and Computer-Aided Engineering (CAE). Nonetheless, this integration has not really been achieved. There is a well established communication from design to analysis, but there is a lack of design operations and functionalities within an analysis environment. This lack of integration will always be presented as long as there are used different representation schemes for design and analysis. Hence, Embodiment Mesh Processing (EMP) is based on a common mesh representation and it aims to provide mesh-based modeling functionalities within an analysis environment. We present our reasoning behind EMP and the needed building blocks for enabling a fully integrated design-analysis interaction loop and the exploration of design variations.

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Stork, André; Wagner, Mathias; Schneider, Peter; Hinnerichs, Andreas; Bruder, Thomas

FunctionalDMU: Co-Simulation mechatronischer Systeme in einem DMU-Umfeld

2010

ProduktDaten Journal, (2010), 1, pp. 44-48

Für die strukturierte Einführung und den Einsatz von FDMU wurde eine Modellierungs-, Integrations- und Nutzungsmethodik entwickelt. Diese erlauben dem Benutzer z.B. eine flexible Nutzung von Simulatoren und Hardware, eine schnelle Beschreibung des Gesamtverhaltens, sowie ein Erkennen von Fehlern in früheren Phasen der Produktentwicklung. Die Umsetzbarkeit domänenübergreifender Simulationen wurde anhand des beschriebenen Szenarios plus zweier weiterer Szenarien (elektrischer Fensterheber und Lenkungsprüfstand) nachgewiesen.

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Santos, Pedro; Pereira, João Madeiras; Stork, André

Guest Editorial of the Special Issue on Improving Display and Rendering Technologies for Virtual Environments

2010

Journal of Real-Time Image Processing, Vol.5 (2010), 2, pp. 71-72. First published as Online First, 5 February 2010, DOI 10.1007/s11554-010-0152-y

The five papers included in this special issue cover different representative contexts of use of tiled display technology, realistic real-time rendering to seamlessly combine virtual and real objects, new real-time interaction metaphors for human-computer interaction within largescale VR scenarios, low-cost real-time marker-less largearea tracking systems and applicability of both types of display devices (near-to-the-eye and large-screen displays) in the collaborative industrial product development process.

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Ritz, Martin; Scholz, Manuel; Goesele, Michael; Stork, André

High Resolution Acquisition of Detailed Surfaces with Lens-Shifted Structured Light

2010

Artusi, Alessandro (Ed.) et al.: VAST 2010. : Eurographics Symposium Proceedings. Goslar: Eurographics Association, 2010, pp. 1-8; 179 (Color plate)

International Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST) <11, 2010, Paris, France>

We present a novel 3D geometry acquisition technique at high resolution based on structured light reconstruction with a low-cost projector-camera system. Using a 1D mechanical lens-shifter extension in the projector light path, the projected pattern is shifted in fine steps at sub-pixel scale with a granularity of down to 2048 steps per projected pixel, which opens up novel possibilities in depth accuracy and smoothness for the acquired geometry. Combining the mechanical lens-shifter extension with a multiple phase shifting technique yields a measuring range of 120x80 mm while at the same time providing a high depth resolution of better than 100 micron. Reaching far beyond depth resolutions achieved by conventional structured light scanning approaches with projector-camera systems, depth layering effects inherent to conventional techniques are fully avoided. Relying on low-cost consumer products only, we reach an area resolution of down to 55 micron (limited by the camera). We see two fields of benefit. Firstly, our acquisition setup can reconstruct finest details of small Cultural Heritage objects such as antique coins and thus digitally preserve them in appropriate precision. Secondly, our accurate height fields can be viable input to physically based rendering in combination with measured material BRDFs to reproduce compelling spatially varying, material-specific effects.

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Binotto, Alecio; Daniel, Christian G.; Weber, Daniel; Kuijper, Arjan; Stork, André; Pereira, Carlos Eduardo; Fellner, Dieter W.

Iterative SLE Solvers over a CPU-GPU Platform

2010

IEEE Computer Society: Proceedings 2010 12th IEEE International Conference on High Performance Computing and Communications : HPCC 2010. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2010, pp. 305-313

IEEE International Conference on High Performance Computing and Communications (HPCC) <12, 2010, Melbourne, Australia>

GPUs (Graphics Processing Units) have become one of the main co-processors that contributed to desktops towards high performance computing. Together with multi-core CPUs, a powerful heterogeneous execution platform is built for massive calculations. To improve application performance and explore this heterogeneity, a distribution of workload in a balanced way over the PUs (Processing Units) plays an important role for the system. However, this problem faces challenges since the cost of a task at a PU is non-deterministic and can be influenced by several parameters not known a priori, like the problem size domain. We present a comparison of iterative SLE (Systems of Linear Equations) solvers, used in many scientific and engineering applications, over a heterogeneous CPU-GPUs platform and characterize scenarios where the solvers obtain better performances. A new technique to improve memory access on matrix vector multiplication used by SLEs on GPUs is described and compared to standard implementations for CPU and GPUs. Such timing profiling is analyzed and break-even points based on the problem sizes are identified for this implementation, pointing whether our technique is faster to use GPU instead of CPU. Preliminary results show the importance of this study applied to a real-time CFD (Computational Fluid Dynamics) application with geometry modification.

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Huff, Rafael; Neves, Tiago; Gierlinger, Thomas; Kuijper, Arjan; Stork, André; Fellner, Dieter W.

OpenCL vs. CUDA for Ray Tracing

2010

Brazilian Computer Society (SBC): XII Symposium on Virtual and Augmented Reality : SVR 2010. Brazil: Everton Cavalcante, 2010, 4 p.

Symposium on Virtual and Augmented Reality (SVR) <12, 2010, Natal, Brazil>

For many years the Graphics Processing Unit (GPU) of common desktops was just used to accelerate certain parts of the graphics pipeline. After developers had access to the native instruction set and memory of the massive parallel computational elements of GPUs a lot has changed. GPUs became powerful and programmable. Nowadays two SDKs are most used for GPU programming: CUDA and OpenCL. CUDA is the most adopted general purpose parallel computing architecture for GPUs but is restricted to Nvidia graphic cards only. In contrast, OpenCL is a new royalityfree framework for parallel programming intended to be portable across different hardware manufacturers or even different platforms. In this paper, we evaluate both solutions considering a typical parallel algorithm: Ray Tracing. We show our performance results and experiences on developing both implementations that could be easily adapted to solve other problems.

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Gierlinger, Thomas; Danch, Daniel; Stork, André

Rendering Techniques for Mixed Reality

2010

Journal of Real-Time Image Processing, Vol.5 (2010), 2, pp. 109-120

In mixed reality (MR) design review, the aesthetics of a virtual prototype is assessed by integrating a virtual model into a real-world environment and inspecting the interaction between the model and the environment (lighting, shadows and reflections) from different points of view. The visualization of the virtual model has to be as realistically as possible to provide a solid basis for this assessment and interactive rendering speed is mandatory to allow the designer to examine the scene from arbitrary positions. In this article we present a real-time rendering engine specifically tailored to the needs of MR visualization. The renderer utilizes pre-computed radiance transfer to calculate dynamic soft-shadows, high dynamic range images and image-based lighting to capture incident real-world lighting, approximate bidirectional texture functions to render materials with self-shadowing, and frame post-processing filters (bloom filter and an adaptive tone mapping operator). The proposed combination of rendering techniques provides a trade-off between rendering quality and required computing resources which enables high quality rendering in mobile MR scenarios. The resulting image fidelity is superior to radiosity-based techniques because glossy materials and dynamic environment lighting with soft-shadows are supported. Ray tracing-based techniques provide higher quality images than the proposed system, but they require a cluster of computers to achieve interactive frame rates which prevents these techniques from being used in mobile MR (especially outdoor) scenarios. The renderer was developed in the European research project IMPROVE (FP6-IST-2-004785) and is currently extended in the MAXIMUS project (FP7-ICT-1-217039) where hybrid rendering techniques which fuse PRT and ray tracing are developed.

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Stork, André

Shedding Light on the Virtual World

2010

Projects, (2010), 18, pp. 76-78

The MAXIMUS project has developed a cutting-edge interactive, high dynamic range visualisation system that specifically supports designers who need to assess a virtual model for its shape and appearance in different lighting conditions. This article describes how the system works and the benefits it will bring to the whole design and production process.

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Peña Serna, Sebastian; Stork, André; Fellner, Dieter W.

Tetrahedral Mesh-Based Embodiment Design

2010

The American Society of Mechanical Engineers (ASME): ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference : DETC 2010. New York: The American Society of Mechanical Engineers, 2010, 10 p.

ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (DETC) <2010, Montreal, Quebec, Canada>

The engineering design is a systematic approach implemented in the product development process, which is composed of several phases and supported by different tools. Computer-Aided Design (CAD) and Computer-Aided Engineering (CAE) tools are particularly dedicated to the embodiment phase and these enable engineers to design and analyze a potential solution. Nonetheless, the lack of integration between CAD and CAE restricts the exploration of design variations. Hence, we aim at incorporating functionalities of a CAD system within a CAE environment, by means of building a high level representation of the mesh and allowing the engineer to handle and manipulate semantic features, avoiding the direct manipulation of single elements. Thus, the engineer will be able to perform extruding, rounding or dragging operations regardless of geometrical and topological limitations. We present in this paper, the intelligence that a simulating mesh needs to support, in order to enable such operations.

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Scholz, Manuel; Danch, Daniel; Stork, André

An Analog Lens-Shifting Device for Digital Fringe Projection

2009

Yu, Jingyi (Chair) et al.: PROCAMS 2009. IEEE International Workshop on Projector-Camera Systems [online] : In conjunction with CVPR 2009. [cited 18 December 2009] Available from: http://graphics.cis.udel.edu/2009/ProCams%20program.htm; http://graphics.cis.udel.edu/2009/poster/posters.pdf, 2009, 2 p.

International Workshop on Projector-Camera Systems (PROCAMS) <6, 2009, Miami, FL, USA >

In this paper, we propose a novel lens-shifting device for digital fringe projection to compensate for today's resolution constraints. We want to apply it to a low-cost, high resolution range scanner to capture the mesostructure of planar material samples. In contrast to traditional DLP-based range scanners our system overcomes the limitation of discrete shifting distance usually limited by projector resolution while at the same time preserving the flexibility of such a system. We extended our DLP projector by an analog, 1-DOF lens-shifter that is inspired by digital camera image stabilizers to increase control over the projected signal. Additionally we evaluate our approach and prove that the projected pattern can be shifted with subpixel accuracy.

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Peña Serna, Sebastian; Stork, André

Computer Design in Computational Mechanics

2009

Antoniou, G. E. (Ed.) et al.: Proceedings of the International Conference on Computing, Engineering and Information : ICC 2009. Los Alamitos, Calif.: IEEE Computer Society, 2009, pp. 329-332

International Conference on Computing, Engineering and Information (ICC) <2009, Fullerton, CA, USA>

The computational mechanics suffers a lack of modifiability and interactivity, which leads to neglecting its potential to help engineers in solving problems faster and cheaper. The fully integration of computer design in computational mechanics will tackle this problems, by means of providing the capability to explore design variations within an analysis environment and with a direct feedback from the mechanical simulation. Our paper states the advantages of such a solution and presents a theoretical concept, which can enrich computational mechanics with modeling functionalities from computer design, enabling a design-analysis iteration loop.

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Peña Serna, Sebastian; Stork, André

Dynamic Simplicial Meshes

2009

ACM SIGGRAPH: Siggraph 2009. Full Conference DVD-ROM. New York: ACM Press, 2009. (Computer Graphics Annual Conference Series), 1 p.

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH) <36, 2009, New Orleans, LA, USA>

Dynamic simplicial meshes will enable real time unconstrained deformation of triangular and tetrahedral meshes regardless of topological limitations, by means of combining a quality measure with complex topological operations and smoothing techniques, which automatically improve and maintain the quality of the mesh, aiming at mesh and geometry processing applications.

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Peña Serna, Sebastian; Silva, Joao; Stork, André; Marcos, Adérito

Effective Algorithm for Building and Solving Linear Systems

2009

Coelho, António (Ed.) et al.: 17º EPCG - Encontro Português de Computação Gráfica, pp. 143-148

Encontro Português de Computação Gráfica (EPCG) <17, 2009, Porto Salvo, Portugal>

Several mesh-based techniques in computer graphics such as shape deformation, mesh editing, animation and simulation, build and solve linear systems. The most common method to build a linear system consists in traversing the topology (connectivity) of the mesh, producing in general a representation of the set of equations in form of a sparse matrix. Similarly, the solution of the system is achieved, by means of iterating over the set of equations in the default sequence of the vertices (unknowns). This paper presents a new algorithm, which optimizes the build of the linear system and its storage, and which allows the iteration over the set of equations in any arbitrary order. Additionally, our algorithm enables rapid modifications to the linear system, avoiding a complete rebuild.

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Dokken, Tor; Koziuk, Michal; Kwoska, Lukasz; Stork, André; Quak, Ewald

Higher Order Shape Representations for Increased Quality of Experience in 3D Internet

2009

International Association for Development of the Information Society (IADIS): IADIS Multi Conference on Computer Science and Information Systems 2009 : MCCSIS 2009. IADIS Press, 2009, pp. 297-302

IADIS Multi Conference on Computer Science and Information Systems (MCCSIS) <2009, Algarve, Portugal>

The user quality of experience of current 3D Internet technology lags far behind the one of installed 3D applications. We believe that a broad uptake of "3D Media Internet" depends on a significant improvement of the user quality of experience, which should not significantly differ from the quality offered by similar 3D services installed on the user's device. The approach we propose combines compact shape representations with the use of the parallel computational performance of GPUs, multi-core CPUs and many-core CPUs.

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Weber, Daniel; Kalbe, Thomas; Goesele, Michael; Stork, André

Interactive Deformable Models with Quadratic Bases in Bernstein-Bézier Form

2009

Darmstadt, 2009

We present a physically based interactive simulation technique for deformable objects with curved boundary surfaces. Our method models the object geometry as well as the displacements using quadratic basis functions in Bernstein-Bézier-form on a tetrahedral finite element grid. The Bernstein-Bézier formulation yields significant advantages compared to approaches with linear and quadratic bases in monomial form. Spatial derivatives and integrals of the displacement field are obtained analytically avoiding the need for numerical evaluations of the elements' stiffness matrices. We validate our approach on several different models and demonstrate state-of-the-art results in terms of accuracy and perfomance.

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Peña Serna, Sebastian; Stork, André

Mesh-Based Modeling Towards Engineering Analysis

2009

International Association for the Engineering Analysis Community (NAFEMS): The Analysis Advantage: Perspectives on Engineering Simulation for Today and Beyond. : NWC 2009. NAFEMS World Congress [Book of Abstracts & CD-ROM]. Glasgow: NAFEMS, 2009, 11 p.

International Congress on Simulation Technology for the Engineering Analysis Community (NWC) <2009, Crete, Greece>

The engineering analysis is the stage of the product design process, where the engineer evaluates a digital prototype, by means of combining shapes and dimensions with materials through physical laws. Unfortunately, this stage only allows the engineer to assess, whether the digital prototype fulfill the requirements or not, but she/he does not have the opportunity to explore design variations, which could lead to improvements in the model. Such an exploration would provide interaction and therefore enrichment to the analysis, since different variations of the same model could be verified and optimized. This paper presents a mesh-based modeling concept for tetrahedral meshes, where CAD-like modifications can be applied to digital prototypes, keeping the quality of the tetrahedral elements and therefore the soundness of the following simulation. In order to keep the quality of the tetrahedral mesh during modifications such as face extrusion, blending change or feature dragging, the topology and the geometry of the tetrahedral mesh are locally adjusted. This adjustment is obtained by a combination of complex topological operations and smoothing techniques, improving the quality of 1-ring vertices and not only of single elements. This method finds an appropriate configuration of the local mesh, which provides a correct interpolation of the mesh nodes. This local configuration is found by evaluating a quality function, which optimizes the gradient of a vertex regarding the 1-ring vertex. The correct interpolation of the mesh nodes generates a low condition number of the simulating linear system, a well-conditioned problem and therefore accuracy in the solution. The proposed concept will allow engineers to interact during the analysis stage and explore different combinations and variations of a digital prototype, by means of modifying the domain and re-simulating its physical behavior. This interaction loop will generate faster optimizations, reducing the time to market of a product and providing engineers with a functionality to better understand how different features influence the solution of a problem.

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Peña Serna, Sebastian; Silva, Joao; Stork, André; Marcos, Adérito

Neighboring-based Linear System for Dynamic Meshes

2009

Prautzsch, Hartmut (Ed.) et al.: VRIPHYS 09: 6th Workshop in Virtual Reality Interactions and Physical Simulations. Proceedings. Goslar: Eurographics Association, 2009, pp. 95-103

International Workshop in Virtual Reality Interaction and Physical Simulations (VRIPhys) <6, 2009, Karlsruhe, Germany>

A linear system is a fundamental building block for several mesh-based computer graphics applications such as simulation, shape deformation, virtual surgery, and fluid/smoke animation, among others. Nevertheless, such a system is most of the times seen as a black box and algorithms do not deal with its optimization. Depending on the number of unknowns, the linear system is often considered as an obstacle for real time application and as a building block for offline computations. We present in this paper, a neighboring-based methodology for representing a linear system. This new representation enables a compact storage of the set of equation, flexibility for ordering the unknowns and a rapid iterative solution, by means of an optimized matrix-vector multiplication. In addition, this representation facilitates the modification of part of the linear system without affecting its unchanged part and avoiding the complete rebuild of the system. This specially benefits applications dealing with dynamic meshes, where the geometry, the topology or both are constantly changed. We present the capabilities of our methodology in models with different sizes and for different operations, highlighting the dynamic characteristic of the mesh. We believe that several applications in computer graphics could benefit from our methodology, in order to improve their convergence and their performance, reducing the number of iterations and the computation time.

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Bein, Matthias; Havemann, Sven; Stork, André; Fellner, Dieter W.

Sketching Subdivision Surfaces

2009

Grimm, Cindy (Ed.) et al.: ACM SIGGRAPH / Eurographics Symposium on Sketch-Based Interfaces and Modeling 2009. Proceedings. New York: ACM, 2009, pp. 61-68

ACM SIGGRAPH / Eurographics Symposium on Sketch-Based Interfaces and Modeling (SBIM) <6, 2009, New Orleans, LA, USA>

We describe a 3D modeling system that combines subdivision surfaces with sketch-based modeling in order to meet two conflicting goals: ease of use and fine-grained shape control. For the excellent control, low-poly modeling is still the method of choice for creating high-quality 3D models, e.g., in the games industry. However, direct mesh editing can be very tedious and time consuming. Our idea is to include also stroke-based techniques for rapidly modeling regular surface parts. We propose a simple and efficient algorithm for converting a 2D stroke to a control polygon suitable for Catmull/Clark subdivision surfaces. We have realized a small but reasonably rich set of interactive modeling tools to assess the expressiveness of stroke-based mesh design with a number of examples.

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Santos, Pedro; Schmedt, Hendrik; Hohmann, Sebastian; Stork, André

The Hybrid Outdoor Tracking Extension for the Daylight Blocker Display

2009

Inakage, Masa (Ed.): Siggraph Asia 2009. New York: ACM Press, 2009, 1 p.

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH Asia) <2, 2009, Yokohama, Japan>

From UMPCs to SmartPhones, we witness the emergence of highly integrated mobile computing platforms which boast higher performance than any of their preceeding systems. However, due to the equally growing demand for ever more complex applications such as mixed reality applications for outdoor scenarios, the need for an efficient distribution of resources for the different application tasks remains. In particular pose estimation in outdoor environments still presents a major ongoing challenge. Since mobile platforms have limited performance, the best approach for real-time pose estimation is using sensor fusion combining optical and inertial sensors. However different algorithms using different sensors require varying amounts of processing power (e.g. there are peaks when processing key frames for feature point detection). In this paper we introduce a novel sensor fusion pose estimation approach which we combine with the first compact daylight blocking optical stereo see-through display for mixed reality we presented a year ago [Santos et al. 2008a] [Santos et al. 2008b]. Through two new feature matching algorithms and appropriate sequencing of tracking algorithms using different sensors we attempt to achieve time-constant tracking update rates while keeping efforts for pose estimation at a fixed share of the overall available computing performance. By doing so we are able to guarantee the main mixed reality application a fixed share of the remaining computing performance on the mobile platform while preserving high tracking stability.

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Binotto, Alecio; Freitas, Edison P.; Wehrmeister, Marco A.; Pereira, Carlos Eduardo; Stork, André; Larsson, Tony

Towards Task Dynamic Reconfiguration over Asymmetric Computing Platforms for UAVs Surveillance Systems

2009

Scalable Computing: Practice and Experience, Vol.10 (2009), 3, pp. 277-289

High-performance platforms are required by modern applications that make use of massive calculations. Actually, low-cost and high-performance specific hardware (e.g. GPU) can be a good alternative along with CPUs, which turned to multiple cores, forming powerful heterogeneous desktop execution platforms. Therefore, self-adaptive computing is a promising paradigm as it can provide flexibility to explore different computing resources, on which heterogeneous cluster can be created to improve performance on different execution scenarios. One approach is to explore runtime tasks migration among node's hardware towards an optimal system load-balancing aiming at performance gains. This way, time requirements and its crosscutting behavior play an important role for task (re)allocation decisions. This paper presents a self-rescheduling task strategy that makes use of aspect-oriented paradigms to address non-functional application timing constraints from earlier design phases. A case study exploring Radar Image Processing tasks is presented to demonstrate the proposed approach. Simulations results for this case study are provided in the context of a surveillance system based on Unmanned Aerial Vehicles (UAVs).

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Wendt, Lars Henning; Stork, André (Betreuer)

3D Rekonstruktion aus perspektivischen Konzeptzeichnungen

2008

Darmstadt, TU, Diplomarbeit, 2008

In dieser Arbeit wird ein Verfahren vorgestellt, das aus Konzeptzeichnungen 3D-Modelle rekonstruiert. Die Zielsetzung ist es dabei möglichst wenig Benutzerinteraktion zu verlangen und keine Kenntnisse in geometrischer Modellierung beim Benutzer voraus zusetzen. Infolgedessen kann ein solches Verfahren als Ergänzung zu herkömmlichen Modellierungsprogrammen eingesetzt werden, um es professionellen Zeichnern zu ermöglichen ihre 3D-Konzepte zu digitalisieren. Um ein digitales 3D-Modell zu berechnen, werden die Konzeptzeichnungen in Kurven zerlegt. Zu diesen werden entsprechende 3D-Kurven rekonstruiert. Daraus resultiert ein Drahtgittermodell. In diesem Verfahren werden die Endpunkte und die Form der 3D-Kurven getrennt voneinander bestimmt. Zur Bestimmung der Position der 3D-Endpunkte wird der Objektraum disktretisiert. Für die so entstandenen Voxel werden die zugehörigen 2D-Endpunkte der Kurven durch Projektion des Voxels in die Zeichnungen berechnet. Daraufhin werden die Voxel anhand der Konnektivität der für sie berechneten 2D-Endpunkte bewertet. Infolge dieser Bewertung werden die 3D-Endpunkte und ihre Konnektivität bestimmt. Zum Finden der Form der 3D-Kurven wird die 2D-Kurve perspektivisch in den Objektraum extrudiert. Durch das Anpassen eines Polygonzugs, zwischen den berechneten 3D-Endpunkten, auf diese Oberfläche wird die 3D-Kurve approximiert.

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Santos, Pedro; Gierlinger, Thomas; Machui, Oliver; Stork, André

An Innovative Daylight Blocking Optical Stereo See-Through HMD

2008

ACM SIGGRAPH: Siggraph 2008. Full Conference DVD-ROM. New York: ACM Press, 2008. (Computer Graphics Annual Conference Series), 1 p.

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH) <35, 2008, Los Angeles, CA, USA>

In this poster we present an innovative daylight blocking optical stereo see-through HMD. Its outstanding capability is to pixelwise block incident daylight before super-imposing virtual content on the real scene. By doing so the device allows to seamlessly mix real and virtual content without the well-known effects of other optical see-through displays where real content will always shine through virtual content (ghosting).

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Danch, Daniel; Stork, André (Betreuer); Gierlinger, Thomas (Betreuer)

Color Bleeding in dynamischen Szenen

2008

Weimar, Univ., Diplomarbeit, 2008

Sekundäre Beleuchtungseffekte sind ein integraler Bestandteil der fotorealistischen Bildsynthese. Bestehende Verfahren aus dem Umfeld des Precomputed Radiance Transfer (PRT) berücksichtigen das Interreflexionsphänomen ausschließlich im Kontext statischer Szenen. PRT-basierte Verfahren für die Bildsynthese in dynamischen Szenen beschränken sich hingegen auf die alleinige Simulation von Verschattungseffekten. In der vorliegenden Diplomarbeit werden bestehende feldbasierte PRT-Verfahren um eine neuartige Transportoperatorrepräsentation für niederfrequente Beleuchtungseffekte erweitert. Das beschriebene Verfahren ermöglicht die effiziente Interreflexionsberechnung in starr-dynamischen Szenen, wobei sowohl Objekte als auch Lichtquellen interaktiv zur Laufzeit manipuliert werden können. Die stetige Form des entwickelten Transportoperators bildet global eingehende Strahlungsdichte für eine Szenenentität in eingehende Strahlungsdichte im freien Raum um diese ab. Seine 7-dimensionale Kernfunktion beschreibt die Transformation von eingehender Strahlungsdichte in eingehende Strahlungsdichte nach der Interaktion mit einem Objekt. Analog zu bisherigen Ansätzen wird während der Akquisitionsphase die direktionale Komponente mittels Kugelfunktionen diskretisiert. Für die Ortskomponente wird ein interpolativer Projektionsansatz gewählt. Mit dem Ziel die Approximationsgüte zu verbessern, werden zudem die Objekte einer Szene vorab einem Segmentierungsprozess unterzogen. Zusätzlich zu der Akquisition des Transportoperators erfolgt die Tabellierung der Verschattungseffekte einer Szene. Die Bildsynthesephase des vorgestellten Verfahrens ist in zwei Schritte unterteilt. Unter Berücksichtigung der Interreflexionseffekte benachbarter Segmente wird zunächst die akkumulierte eingehende Strahlungsdichte für jedes der die Szene definierenden Segmente bestimmt. Hierbei wird der direkt eingehende Strahlungsdichteanteil mit der vorberechneten Verschattungsrepräsentation moduliert. Der indirekte Anteil ergibt sich aus der rekursiven Propagation der eingehenden Strahlungsdichte in der Szene unter Verwendung der entsprechenden Repräsentationen für den Transportoperator sowie der Verschattung. In einem abschließenden Arbeitsschritt wird die abgehende Strahlungsdichte für jeden Oberflächenpunkt einer Szene bestimmt. Zu diesem Zweck wird zunächst die eingehende Strahlungsdichte, die sich aus direkt eingehender und interreflektierter Strahlungsdichte zusammensetzt, für jeden Oberflächenpunkt bestimmt. Im Anschluss wird dann die abgehende Strahlungsdichte durch eine einfache Faltung mit der BRDF des Oberflächenpunktes erhalten. In dieser Diplomarbeit wurde ein neuartiges, PRT-basiertes Renderingverfahren entwickelt, welches bestehende feld-basierte Verfahren für dynamische Szenen um den Aspekt der Interreflektion mit beliebiger Rekursionstiefe erweitert. Obwohl lediglich eine CPU-basierte Implementierung realisiert wurde, konnten interaktive Reaktionszeiten für Szenen mittlerer Komplexität erreicht werden. Zukünftig ist eine Portierung des Verfahrens auf die GPU geplant. Zudem sollen geeignete Kompressionstechniken den Speicherverbrauch minimieren helfen.

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Bellofiore, Vincenzo; Stork, André (Betreuer); Henn, Thomas (Betreuer)

Development of Functional Digital Mock-Ups of Mechanisms in Virtual Reality

2008

Napoli, Univ., Master Thesis, 2008

The research activity this thesis deals with was born in the context of the framework Functional DMU. Modern CAD systems are limited to proprietary formats and licensed APIs are not available for inheriting kinematic joints and constraints from the native CAD assembly. Different simulation applications are still conceived as stand-alone solutions and lack of functional integration. The interplay of different engineering simulation tools requires an appropriate methodical approach for sharing digital meta-models in the simulation software loop, i.e. functional digital mock-ups which can assure to the digital prototype of mechanical devices a consistent set of kinematic data since the first design steps. Functional digital mock-ups guarantee interoperability and integration of the digital model under test into a wider framework of simulation tools, as it is typical of the concurrent engineering and multi-domain design approach. The developed methodology is tested on the case study visco-lock differential gear. In the proposed solution the designer starts with modeling the CAD geometry, where datum references such as points, lines, curves, axes or surfaces can be properly added to enhance digital mock-ups functionally: they represent the main skeleton to define functional requirements, which parts may match in the assembly via kinematic joints. As sharable meta-data they take into account further key characteristics which other downstream applications should involve and have to test. An appropriate selective conversion into a standard data-exchange format, like STEP, ensures methodically the export/import phase of geometry and datum references for further evaluations among different destination software tools. A semi-immersive virtual environment is set up as interactive visualization to perform accurate Design Review sessions. A dynamic library of joint types in the kinematic module of Virtual Design 2 is implemented to make the best of the great potential Virtual Reality technologies can offer. This way the virtual environment can be enhanced to perform kinematic analysis on complex mechanical devices. Furthermore the deep investigation on the central role the dynamic multibody solver ADAMS plays, has furnished the possibility of developing a generalized converter architecture, which matches properly the idea of functional integration. New research goals could be pointed out in order to bring dynamics into virtual environment by importing kinematic and dynamic data from MBS solvers as well as using their dynamic engine to drive the virtual interactive simulation. So far in coupling mode with ADAMS, the basic event-driven paradigm of Virtual Design 2 can be properly used for programming the virtual scene for direct manipulation of dynamic objects, which refer to the functional DMU of mechanism under test.

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Freitas, Edison P.; Binotto, Alecio; Pereira, Carlos Eduardo; Stork, André; Larsson, Tony

Dynamic Reconfigurable Task Schedule Support Towards a Reflective Middleware for Sensor Network

2008

IEEE Computer Society: Proceedings of the 2008 International Symposium on Parallel and Distributed Processing with Applications : ISPA 2008. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2008, p. 886-891

International Symposium on Parallel and Distributed Processing with Applications (ISPA) <6, 2008, Sydney, Australia>

Sensor networks are being applied in several emerging sophisticated applications due to the use of powerful and high-quality sensor nodes, such as radars and visible light cameras. However, these nodes need additional features to optimally benefit from heterogeneous modern computing platforms. Therefore, reconfigurable computing is a potential paradigm for those scenarios as it can provide flexibility to explore the computational resources on that kind of high performance computing system. This paper presents a reconfigurable sensor node allocation support, based on application requirements, provided by a middleware focused on heterogeneous sensor networks. In order to address this concern, an aspect-orientation paradigm and intelligent agents approach is proposed followed by an UAV case study.

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Freitas, Edison P.; Binotto, Alecio; Pereira, Carlos Eduardo; Stork, André; Larsson, Tony

Dynamic Reconfiguration of Tasks Applied to an UAV System Using Aspect Orientation

2008

IEEE Computer Society: Proceedings of the 2008 International Symposium on Parallel and Distributed Processing with Applications : ISPA 2008. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2008, pp. 292-300

International Symposium on Parallel and Distributed Processing with Applications (ISPA) <6, 2008, Sydney, Australia>

Many modern applications require highperformance platforms to deal with a variety of algorithms requiring massive calculations. Moreover, low-cost powerful hardware (e.g., GPU, PPU) and CPUs with multiple cores have become abundant, and can be combined in heterogeneous architectures. To cope with this, reconfigurable computing is a potential paradigm as it can provide flexibility to explore the computational resources on hybrid and multi-core desktop architectures. The workload can optimally be (re)distributed over heterogeneous cores along the lifecycle of an application, aiming for best performance. As the first step towards a run-time reconfigurable load-balancing framework, application requirements and crosscutting concerns related to timing play an important role for task allocation decisions. In this paper, we present the use of aspect-oriented paradigms to address non-functional application timing constraints in the design phase. The DERAF aspects' framework is extended to support reconfiguration requirements; and a strategy for load-balancing is described. In addition, we present preliminary evaluation using an Unmanned Aerial Vehicle (UAV) based Surveillance System as case study.

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Binotto, Alecio; Freitas, Edison P.; Götz, Marcelo; Pereira, Carlos Eduardo; Stork, André; Larsson, Tony

Dynamic Self-Rescheduling of Tasks over a Heterogeneous Platform

2008

IEEE Computer Society: Proceedings 2008 International Conference on Reconfigurable Computing and FPGAs : ReConFig 2008. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2008, pp. 253-258

International Conference on Reconfigurable Computing and FPGAs (ReConFig) <2008, Cancun, Mexico>

Modern applications require powerful highperformance platforms to deal with many different algorithms that make use of massive calculations. At the same time, low-cost and high-performance specific hardware (e.g., GPU, PPU) are rising and the CPUs turned to multiple cores, characterizing together an interesting and powerful heterogeneous execution platform. Therefore, self-adaptive computing is a potential paradigm for those scenarios as it can provide flexibility to explore the computational resources on heterogeneous cluster attached to a highperformance computer system platform. As the first step towards a run-time reschedule load-balancing framework targeting that kind of platform, application time requirements and its crosscutting behaviour play an important role for task allocation decisions. This paper presents a strategy for self-reallocation of specific tasks, including dynamic created ones, using aspect-oriented paradigms to address non-functional application timing constraints in the design phase. Additionally, as a case study, a special attention on Radar Image Processing will be given in the context of a surveillance system based on Unmanned Aerial Vehicles (UAV).

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Binotto, Alecio; Pereira, Carlos Eduardo; Stork, André; Larsson, Tony

Real-time Task Reconfiguration Support Applied to an UAV-based Surveillance System

2008

Ganzha, M. (Ed.) et al.: Proceedings of the International Multiconference on Computer Science and Information Technology : Volume 3 (2008). Los Alamitos, Calif.: IEEE Computer Society Press, 2008, pp. 581-588

International Multiconference on Computer Science and Information Technology (IMCSIT) <2008, Wisla, Poland>

Modern surveillance systems, such as those based on the use of Unmanned Aerial Vehicles, require powerful high performance platforms to deal with many different algorithms that make use of massive calculations. At the same time, lowcost and high-performance specific hardware (e.g., GPU, PPU) are rising and the CPUs turned to multiple cores, characterizing together an interesting and powerful heterogeneous execution platform. Therefore, reconfigurable computing is a potential paradigm for those scenarios as it can provide flexibility to explore the computational resources on heterogeneous cluster attached to a high-performance computer system platform. As the first step towards a run-time reconfigurable workload balancing framework targeting that kind of platform, application time requirements and its crosscutting behavior play an important role for task allocation decisions. This paper presents a strategy to reallocate specific tasks in a surveillance system composed by a fleet of Unmanned Aerial Vehicles using aspect oriented paradigms in order to address non-functional application timing constraints in the design phase. An aspect support from a framework called DERAF is used to support reconfiguration requirements and provide the resource information needed by the reconfigurable load-balancing strategy. Finally, for the case study, a special attention on Radar Image Processing will be given.

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Bein, Matthias; Stork, André (Betreuer); Havemann, Sven (Betreuer)

Skizzentechniken auf Combined B-Reps in GML

2008

Darmstadt, TU, Diplomarbeit, 2008

Diese Diplomarbeit untersucht erstmalig interaktive skizzenbasierte Modellierung auf Combined B-Reps in GML (Generative Modeling Language). Die Hauptherausforderungen liegen in der Identifikation brauchbarer und übertragbarer Skizzentechniken, in den Berechnungen des Combined B-Rep Kontrollnetzes und die Entwicklung eines Konzeptes, welches die notwendige Interaktion in GML bereitstellt. In der Diplomarbeit wurde ein iteratives Verfahren entwickelt, welches eine interaktiv gezeichnete Skizze mittels globaler Approximation in ein B-Spline-Kontrollnetz überführt. Das B-Spline-Kontrollnetz dient zur Erstellung des Combined-B-Rep-Kontrollnetzes des 3D-Modells. Weiter wurde ein Modellierungsprogramm in GML implementiert, mit dem 3D-Modelle interaktiv und skizzenbasiert erzeugt und modifiziert werden können. Dabei sind keine Kenntnisse in der Programmiersprache GML notwendig. Lediglich das Konzept der Combined B-Reps sollte dem Benutzer bewusst sein.

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Santos, Pedro; Gierlinger, Thomas; Machui, Oliver; Stork, André

The Daylight Blocking Optical Stereo See-through HMD

2008

IPT/EDT 2008. Proceedings : Immersive Projection Technologies / Emerging Display Technologies Workshop. New York: ACM, 2008, 4 p.

Workshop on Immersive Projection Technology (IPT) <10, 2008, Los Angeles, California, USA>

In this paper we present an innovative daylight blocking optical stereo see-through HMD. Its outstanding capability is to pixelwise block incident daylight before super-imposing virtual content on the real scene. By doing so the device allows to seamlessly mix real and virtual content without the well-known effects of other optical see-through displays where real content will always shine through virtual content. To our knowledge related work on daylight blocking displays is very limited and we present the first commercial HMD available.

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Stork, André; Thole, Clemens-August; Klimenko, Stanislav; Nikitin, Igor; Nikitina, Lialia; Astakhov, Yuri

Towards Interactive Simulation in Automotive Design

2008

The Visual Computer, Vol.24 (2008), 11, pp. 947-953

One of the important tasks in Mechanical Engineering is to increase the safety of the vehicle and decrease its production costs. This task is typically solved by means of Multiobjective Optimization, which formulates the problem as a mapping from the space of design variables to the space of target criteria and tries to find an optimal region in these multidimensional spaces. Due to high computational costs of numerical simulations, the sampling of this mapping is usually very sparse and scattered. Combining design of experiments methods, metamodeling, new interpolation schemes and innovative graphics methods, we enable the user to interact with simulation parameters, optimization criteria, and come to a new interpolated crash result within seconds. We denote this approach as Simulated Reality, a new concept for the interplay between simulation, optimization and interactive visualization. In this paper we show the application of Simulated Reality for solution of real life car design optimization problems.

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Stork, André

Virtuelle mechatronische Produkte werden erlebbar

2008

CAD-CAM REPORT, (2008), 6, pp. 34-37

Produkte sind heute geprägt von mechatronischen Komponenten, bei denen Software auf elektronischen Bauteilen abläuft und mechanische Vorgänge steuert. Immer komplexer werdende Produkte und wachsender Wettbewerbsdruck führen zum Einsatz unterschiedlichster Simulationswerkzeuge, um schon frühzeitig im Entwicklungsprozess funktionale Produkteigenschaften absichern zu können.

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Gierlinger, Thomas; Santos, Pedro; Stork, André

Augmented Reality for Visualization of Architectural Design

2007

Bowen, Jonathan P. (Ed.): EVA London 2007 Conference Proceedings. EVA Conferences International (ECI), 2007, pp. 35.1 - 35.10

Electronic Imaging & the Visual Arts (EVA) <18, 2007, London, UK>

We present the rendering engine of a design review system which is developed in the EU project IMPROVE. It is tailored to Augmented Reality review scenarios. Application scenarios include design review in the architectural domain as well as in the automotive industry. We describe the techniques we employ for rendering as well as steps towards realistic material acquisition. These techniques include High Dynamic Range Imaging, Image Based Lighting, Precomputed Radiance Transfer and Approximate Bidirectional Texture Functions.

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Santos, Pedro; Stork, André; Linaza, María Teresa; Machui, Oliver; McIntyre, Don; Jorge, Elisabeth

CINeSPACE: Interactive Access to Cultural Heritage While On-The-Move

2007

HCI International 2007. [Proceedings CD-ROM] : With 8 further Associated Conferences. Berlin, Heidelberg, New York: Springer, 2007. (Lecture Notes in Computer Science (LNCS)), LNCS 4564, pp. 435-444

International Conference on Online Communities and Social Computing (OCSC) <2, 2007, Beijing, China>

Films are unquestionably a part of Cultural Heritage. Problems of current systems for accessing Cultural Heritage resources which deal with film objects include some of the following aspects: Distributed sources which store huge amounts of information; different formats of the contents ranging from traditional ones such as paper to advanced multimedia objects; and finally, and what is more crucial for the content providers, lack of systems which support currently the needs of the user such as enriched content, interaction with the information, usability, and exchange of experiences with other users. Taking into account these gaps detected by some European cities with a strong connection with the film sector, CINeSPACE a European research project aims at designing and implementing a mobile rich media collaborative information exchange platform, scalable, accessible through a wide variety of networks, and therefore, interoperable and Location-Based for the promotion of Film Heritage, going beyond the current state of the art. CINeSPACE enables users to interact with Location-Based multimedia contents while navigating a city. Audiovisual information will be delivered through a unique and portable low-cost wireless high definition near-to-the-eye display and audio phones. CINeSPACE will also comprise a small camera able to record or send what the user is "seeing". This information can be uploaded to a database through a WLAN hot spot or a 3G connection in order to create collaborative experiences with other end users. This paper presents the current status of development of the project.

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Peña Serna, Sebastian; Stork, André

Combining Modeling, Simulation, Optimization and Analysis under a Unique Framework

2007

Proceedings in Applied Mathematics and Mechanics, (2007), pp. 1011401-1011402

International Congress on Industrial Applied Mathematics (ICIAM) <6, 2007, Zurich, Switzerland>

The virtual engineering design process is based on several phases and every phase is supported by special concepts, representations and tools. This process is complex and the transition and communication between phases is difficult because of conversions and transformations. Embodiment is the phase, which more time requires, in order to produce a definitive layout from the concept, hence, we are designing and developing a unique framework where the embodiment phase can be performed, integrated and combined without transformations and conversions. This approach will support the engineers with advanced techniques on modeling meshes, conceptual simulations and real time optimization.

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Brunetti, Gino; Stork, André

Constraint-based Virtual Conceptual Design

2007

International Journal of Product Development, Vol.4 (2007), 6, pp. 646-661

This paper introduces an approach towards modelling and validation of mechanisms in the conceptual design phase applying virtual reality techniques and kinematics simulation. The presented system allows to interactively assemble mechanisms and to experience their behaviour within the same process. The described approach incrementally builds kinematic chains reducing stepwise degrees of freedom. Kinematics is expressed in terms of joints by geometric constraints, which are solved in real time during interaction with the virtual prototype.

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Santos, Pedro; Gierlinger, Thomas; Stork, André; McIntyre, Don

Display and Rendering Technologies for Virtual and Mixed Reality Design Review

2007

Proceedings of the 7th International Conference on Construction Applications of Virtual Reality : CONVR 2007 [Online]. [cited 7 March 2008] Available from: http://www.engr.psu.edu/convr/Proceedings.htm, 2007, pp. 165-175

International Conference on Construction Applications of Virtual Reality (CONVR) <7, 2007, University Park, Pennsylvania, USA>

In this paper we introduce an innovative application designed to make collaborative design review in the architectural and automotive domain more effective. For this purpose we present a system architecture which combines a variety of visualization technologies such as high resolution multi-tile displays, TabletPCs and headmounted displays with innovative 2D and 3D Interaction Paradigms to better support collaborative mobile mixed reality design reviews. Our research and development is motivated by two user scenarios: architectural and automotive design review involving real users from Page\Park architects and FIAT Elasis. Our activities are supported by the EU IST project IMPROVE aimed at developing advanced display techniques, fostering activities in the areas of: optical see-through HMD development using unique OLED technology, marker-less optical tracking, mixed reality rendering, image calibration for large tiled displays, collaborative tablet-based and projection wall oriented interaction and stereoscopic video streaming for mobile users. The paper gives an overview of the targeted scenarios and focuses in particular on the rendering aspects of the project.

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Santos, Pedro; Gierlinger, Thomas; Stork, André

Ein kollaboratives Mixed Reality Design Review System

2007

Gausemeier, Jürgen (Ed.) et al.: Augmented und Virtual Reality in der Produktentstehung : Grundlagen, Methoden und Werkzeuge. Paderborn: Heinz Nixdorf Institut, 2007. (HNI-Verlagsschriftenreihe 209), pp. 159-174

Paderborner Workshop Augmented & Virtual Reality in der Produktentstehung <6, 2007, Paderborn, Germany>

In diesem Beitrag stellen wir ein zukunftsweisendes, kollaboratives Design Review System für Mixed Reality vor für die Bereiche Architektur und Automobildesign. Zu diesem Zweck haben wir eine System Architektur entwickelt, die eine Vielzahl von Visualisierungstechnologien wie beispielsweise hochauflösende "multi-tile" Projektionswände und OLED basierte HMDs mit innovativer 2D und 3D Interaktion kombiniert, um den kollaborativen Design Prozess in Mixed Reality besser zu unterstützen. Unsere Forschung und Entwicklung wird durch zwei Anwendungsszenarien motiviert: Architektur- und Automobildesign unter Mitwirkung von Partnern wie FIAT Elasis in Neapel und Page&Park aus Glasgow. Unsere Forschung wird durch das EU IST Projekt IMPROVE im Bereich "advanced display techniques" gefördert. IMPROVE hat sich zur Aufgabe gesetzt OLED basierte, optische "see-through" HMDs weiterzuentwicklen, Marker-loses optisches Tracking für Aussenanwendungen, GPU-basiertes "mixed-reality rendering", Farbkalibrierung von "multi-tile" Projektionswänden, kollaborative Interkation über TabletPCs und an Projektionswänden, sowie Stereo-Videoübertragung zu mobilen Endgeräten über WLAN, UMTS Netze. Dieser Beitrag gibt einen Überblick über den Stand der momentanen Entwicklungen in IMPROVE.

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Santos, Pedro; Stork, André; Gierlinger, Thomas; Pagani, Alain; Araújo, Bruno; Jota, Ricardo; Bruno, Luis; Jorge, Joaquim; Pereira, João Madeiras; Witzel, Martin; Conti, Giuseppe; Amicis, Raffaele de; Barandarian, Iñigo; Paloc, Céline; Hafner, Maylu; McIntyre, Don

IMPROVE: Advanced Displays and Interaction Techniques for Collaborative Design Review

2007

HCI International 2007. [Proceedings CD-ROM] : With 8 further Associated Conferences. Berlin, Heidelberg, New York: Springer, 2007. (Lecture Notes in Computer Science (LNCS)), LNCS 4563, pp. 376-385

International Conference on Virtual Reality (ICVR) <2, 2007, Beijing, China>

In this paper we present evaluation results of an innovative application designed to make collaborative design review in the architectural and automotive domain more effective. Within IMPROVE, a European research project in the area of advanced displays, we are combining high resolution multi-tile displays, TabletPCs and head-mounted displays with innovative 2D and 3D Interaction Paradigms to better support collaborative mobile mixed reality design reviews. Our research and development is motivated by application scenarios in the automotive domain involving FIAT Elasis from Naples, Italy and in the architectural domain involving Page/Park architects from Glasgow, Scotland. User evaluation took place at Glasgow (UK), Naples (ITA) and Darmstadt (GER), where we tested the integrated IMPROVE prototype application. The tests were conducted based on several heuristics such as ergonomics and psychomotorial factors and they were conducted based on guidelines recommended by ISO 9241 to verify whether the developed interfaces were suitable for the applications scenarios. Evaluation results show that there is a strong demand for more interactive design review systems, allowing users greater flexibility and greater choice of input and visualization modalities as well as their combination.

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Santos, Pedro; Stork, André; Gierlinger, Thomas; Pagani, Alain; Paloc, Céline; Barandiarán, Iñigo; Conti, Giuseppe; Amicis, Raffaele de; Witzel, Martin; Machui, Oliver; Jimenez, Iván; Araújo, Bruno de; Jorge, Joaquim; Bodammer, Georg

IMPROVE: An Innovative Application for Collaborative Mobile Mixed Reality Design Review

2007

IJIDeM - International Journal on Interactive Design and Manufacturing, Vol.1 (2007), 2, pp. 115-126

In this paper we introduce an innovative application aiming at combining large, tablet-based and headmounted displays for collaborative mobile mixed reality design reviews. Our research and development is motivated by two use scenarios: automotive and architectural design review involving real users from Page\Park architects and Elasis FIAT. Our activities are supported by the EU IST project IMPROVE. It covers activities in the areas of: HMD development using unique OLED technology, markerless tracking, augmented reality rendering, image calibration for large tiled displays, collaborative tablet-based and projection wall oriented interaction and stereoscopic video streaming for mobile users. The paper gives an overview of the hardware and software developments within IMPROVE and concludes with results from first user test.

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Santos, Pedro; Stork, André; Gierlinger, Thomas; Pagani, Alain; Araújo, Bruno; Jota, Ricardo; Bruno, Luis; Jorge, Joaquim; Pereira, João Madeiras; Witzel, Martin; Conti, Giuseppe; Amicis, Raffaele de; Barandarian, Iñigo; Paloc, Céline; Machui, Oliver; Jiménez, Jose M.; Bodammer, Georg; McIntyre, Don

IMPROVE: Collaborative Design Review in Mobile Mixed Reality

2007

HCI International 2007. [Proceedings CD-ROM] : With 8 further Associated Conferences. Berlin, Heidelberg, New York: Springer, 2007. (Lecture Notes in Computer Science (LNCS)), LNCS 4563, pp. 543-553

International Conference on Virtual Reality (ICVR) <2, 2007, Beijing, China>

In this paper we introduce an innovative application designed to make collaborative design review in the architectural and automotive domain more effective. For this purpose we present a system architecture which combines variety of visualization displays such as high resolution multi-tile displays, TabletPCs and head-mounted displays with innovative 2D and 3D Interaction Paradigms to better support collaborative mobile mixed reality design reviews. Our research and development is motivated by two use scenarios: automotive and architectural design review involving real users from Page\Park architects and FIAT Elasis. Our activities are supported by the EU IST project IMPROVE aimed at developing advanced display techniques, fostering activities in the areas of: optical see-through HMD development using unique OLED technology, marker-less optical tracking, mixed reality rendering, image calibration for large tiled displays, collaborative tablet-based and projection wall oriented interaction and stereoscopic video streaming for mobile users. The paper gives an overview of the hardware and software developments within IMPROVE and concludes with results from first user tests.

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Santos, Pedro; Stork, André; Gierlinger, Thomas; Pagani, Alain; Araújo, Bruno; Jota, Ricardo; Bruno, Luis; Jorge, Joaquim; Pereira, João Madeiras; Witzel, Martin; Conti, Giuseppe; Amicis, Raffaele de; Barandarian, Iñigo; Paloc, Céline; Hafner, Maylu; McIntyre, Don

IMPROVE: Designing Effective Interaction for Virtual and Mixed Reality Environments

2007

HCI International 2007. [Proceedings CD-ROM] : With 8 further Associated Conferences. Berlin, Heidelberg, New York: Springer, 2007. (Lecture Notes in Computer Science (LNCS)), LNCS 4551, pp. 689-699

International Conference on Human-Computer Interaction (HCII) <12, 2007, Beijing, China>

In this paper we present evaluation results of an innovative application designed to make collaborative design review in the architectural and automotive domain more effective. Within IMPROVE, a European research project in the area of advanced displays, we are combining high resolution multi-tile displays, TabletPCs and head-mounted displays with innovative 2D and 3D Interaction Paradigms to better support collaborative mobile mixed reality design reviews. Our research and development is motivated by application scenarios in the automotive domain involving FIAT Elasis from Naples, Italy and in the architectural domain involving Page/Park architects from Glasgow, Scotland. User evaluation took place at Glasgow (UK), Naples (ITA) and Darmstadt (GER), where we tested the integrated IMPROVE prototype application. The tests were conducted based on several heuristics such as ergonomics and psychomotorial factors and they were conducted based on guidelines recommended by ISO 9241 to verify whether the developed interfaces were suitable for the applications scenarios. Evaluation results show that there is a strong demand for more interactive design review systems, allowing users greater flexibility and greater choice of input and visualization modalities as well as their combination.

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Dehghani, Siamak; Stork, André (Betreuer); Peña Serna, Sebastian (Betreuer)

Interactive Mesh Modification Keeping Surface Quality

2007

Darmstadt, TU, Diplomarbeit, 2007

During the last decades, researchers of the computer graphics community have been developing techniques and methodologies for deforming discrete models (i.e. polygonal-based, point-based, etc.), aiming at animating characters and figures in several ways and fulfilling special constraints (volume preservation, detail preservation, feature preservation, etc.).On the other hand, engineers and designers are becoming familiar with these techniques and methodologies and they are starting to introduce these in the virtual development process. However, these approaches are not totally satisfying the expectations of engineers and designers, because they cannot drive the deformation of the model in the same way as they are used to, i.e. they do not find similar functions, which a CAD software provides. Hence, there is still a gap, which needs to be bridged, in other words the techniques and methodologies from the computer graphics community need to be adapted to the expectations of the engineers and designers, or new techniques need to be developed to fulfill their requirements. I am presenting in this thesis a methodology, which aims at providing similar functionality to engineers and designers as they are used to. This thesis introduces a methodology for increasing and decreasing the curvature of a model, deforming the model as the engineers and designers are used to with CAD software. The method presented here is based on the curvature values of mesh vertices. According to this method the curvature values of the selected points of the mesh are increased or decreased. To perform this type of modification a group of vertices are translated to their new positions. They are moved along their mean curvature normal vectors and their curvature values determine the magnitude of the translation. Deformation occurs in multiple steps and for each iteration the new curvature normal vectors and curvature values are computed. As mentioned above, the computation of the curvature values and mean curvature normal vector are the core of this approach. They are performed based on the paper of Meyer et al. This approach is appropriate for noise-free meshes, because in the presence of noise on the mesh surface two effects can happen: Translating the noise in an incorrect direction and drastic change in curvature values of noises after each iteration. This approach is tested successfully on different noise-free triangular meshes.

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Göllner, Carlo Moritz; Wundrak, Stefan; Segura, Álvaro; Moreno, Aitor; Stork, André

Interactive Visualisation of Simulated Nonwoven Fabrics

2007

Ottjes, Jaap (Ed.) et al.: Industrial Simulation Conference 2007. Proceedings : ISC 2007. Ostend: EUROSIS-ETI, 2007, pp. 426-436

International Industrial Simulation Conference (ISC) <5, 2007, Delft, Netherlands>

The computational simulation of the production of spunbond nonwoven fabrics is a new and emerging field of research. Visualising the outcome of these simulations, large sets of thin randomly oriented fibres, has not yet been scientifically covered. We apply a set of visualisation techniques for the analysis of the simulation data using established methods such as surface reconstruction, parallel coordinates, and colour coding of specific physical fibre properties. Furthermore, we propose a model for realistic rendering of nonwoven fabrics to create a virtual preview of the simulated nonwoven fabric. This is a topic that has not been addressed before. Our model for realistic rendering is based solely on the output of the simulation and relies on existing techniques for realistic rendering of fibrous materials. We use modern programmable graphics hardware to ensure interactive frame rates.

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Stork, André; Danch, Daniel

Mobile Presence - a Computer Graphics Utopia?

2007

Amicis, Raffaele de (Ed.) et al.: 5th Italian Chapter Conference : Eurographics Italian Chapter Proceedings. Aire-la-Ville: Eurographics, 2007, pp. 135-138

Eurographics Italian Chapter Conference <5, 2007, Trento, Italy>

In this paper we set out a future scenario of mobile presence. We will define our understanding of the term mobile presence. We will derive the requirements imposed by mobile presence with respect to computer graphics and computer graphics research. Discussing the state of the art in various fields, we like to identify and stimulate approaches and areas of research relevant to mobile presence now and in the future.

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Madeira, Joaquim; Silva, Samuel; Stork, André; Peña Serna, Sebastian

Principal Curvature-Driven Segmentation of Mesh Models: A Preliminary Assessment

2007

Santos, LuÍs Paulo (Ed.) et al.: 15º EPCG - Encontro Português de Computação Gráfica, pp. 189-194

Encontro Português de Computação Gráfica (EPCG) <15, 2007, Porto Salvo, Portugal>

Three methods for triangle mesh segmentation, based on precomputed principal curvature values and using a region growing algorithm to label the vertices defining distinct surface regions, were developed, aiming at supporting the later manipulation of mesh models. Examples are presented, using different models, to illustrate their behavior. Results are promising but, in some cases, there is a clear need for a further post-processing step to refine the boundaries between adjoining regions and eliminate segmentation artifacts.

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Stork, André; Thole, Clemens-August; Klimenko, Stanislav; Nikitin, Igor; Nikitina, Lialia; Astakhov, Yuri

Simulated Reality in Automotive Design

2007

Wolter, Franz-Erich (Ed.) et al.: 2007 International Conference on Cyberworlds. Proceedings. Los Alamitos, Calif.: IEEE Computer Society, 2007, pp. 23-27

International Conference on Cyberworlds (CW) <6, 2007, Hannover, Germany>

In this paper we introduce Simulated Reality (SR) as a new concept for the interplay between simulation, optimization and interactive visualization. We see SR as a new metaphor for the interactive visual exploration of simulation and optimization results. The vision of Simulated Reality implies interactive behavior of simulations. Fact is today that simulations might still need hours of computation time, especially in crash worthiness. This paper shows approaches to come closer to the vision of SR. Combining design of experiments methods, metamodeling, new interpolation schemes and innovative graphics methods, we enable to user to interact with simulation parameters, optimization criteria and come to a new interpolated crash result within seconds. The approaches have been successfully applied for solution of real life car design optimization problems.

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Graf, Holger; Peña Serna, Sebastian; Stork, André

Towards Conceptual Simulations within Highly Interactive Environments

2007

Arabnia, Hamid R. (Ed.): Proceedings of the 2007 International Conference on Modeling, Simulation & Visualization Methods : MSV 2007. Las Vegas: CSREA Press, 2007, pp. 108-114

International Conference on Modeling, Simulation & Visualization Methods (MSV) <2007, Las Vegas, NV, USA>

During the last few years, 3D interactive tools, such as Virtual Reality have been accepted by several application domains e.g. design and engineering. Nowadays Virtual Reality environments are used for design review purposes, visualization of large data sets or immersive simulations, but have been limited to single domains. Generative tools offer the possibility for new applications in design environments, whereas 4D representations in the engineering domain become feasible at interactive rates (> 30 Hz). This new capabilities increase the expectations of engineers towards fast "whatif" analysis, in which several aspects of the product validation can be tested in interactive sessions. Thus, the aim is to bridge the gap between traditionally separated design and engineering domains, in order to allow Conceptual Simulations for validating and improving the design from an engineering point of view (Design by Simulation). Therefore, we present a new approach and methodologies, which build the fundaments of this concept.

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Hamisu, Pascal; Horvatic, Petar; Encarnação, L. Miguel; Santos, Pedro; Stork, André

A Smart Interface Development Architecture for Device-independent Data Presentation

2006

Grifoni, Patrizia (Ed.) et al.: Proceedings of Multimodal and Pervasive Services MAPS '06 : In Conjunction with IEEE International Conference on Pervasive Services. Lyon, 2006, pp. 18-24

International Workshop on Multimodal and Pervasive Services (MAPS) <1, 2006, Lyon, France>

Off-the-shelf mobile solutions for content retrieval and presentation are often not equipped with means to provide adaptive data presentation and context-sensing techniques. This paper proposes a novel framework based on a device-independent User Interface (UI) standard and using a user-centric modelling scheme for data processing and content presentation. The goal is to have a subset of smart reusable object models with embedded design knowledge to empower engineers to design good interfaces, the system to adapt the interface to data and the end-user to tailor the interfaces to changes in mission, platform and environment.

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Leon, Jean-Claude; Giannini, Franca; Falcidieno, Bianca; Brunetti, Gino; Graf, Holger; Stork, André; Vexo, Frederic; Thalmann, Daniel

Acquiring, Structuring Shapes and Annotating Them with Semantics to Improve Design Activities

2006

Fischer, Xavier (Ed.) et al.: Research in Interactive Design : Proceedings of Virtual Concept 2005. Paris, Berlin, Heidelberg: Springer, 2006, 10 p.

Virtual Concept <2005, Biarritz, France>

Shapes incorporate geometry as well as semantics and can be defined in 2D, 3D or higher dimensions. Geometric models can be structured in such a way that they can provide a relevant framework to insert semantic information or view dependent information about a product to from features. Combining such features with an immersive environment allows the user to interact more efficiently with an object. This framework will be illustrated in the context of free-form surface modelling for aesthetic design and in the context of engineering and simulation, both among the research themes of the network of excellence AIM@SHAPE. Virtual environments can also contribute to the efficiency of the design process through appropriate models of interaction between the objects contributing to a given simulation environment (a maintenance task, a surface deformation process for aesthetic design for example). To this end, virtual humans bring new capabilities to enhance simulations though they require new models of interaction to incorporate the appropriate semantics during an object manipulation. This third aspect is also part of the ongoing research actions of AIM@SHAPE and will be addressed to show how it is complementary to the previous one. As a result, this set of contributions demonstrates how various categories of semantic can enhance the design process within virtual environments.

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Graf, Holger; Peña Serna, Sebastian; Stork, André

Adaptive Quality Meshing for "On-the-fly" Volumetric Mesh Manipulations within Virtual Environments

2006

IEEE Instrumentation and Measurement Society: VECIMS 2006 : Proceedings of 2006 IEEE International Conference on Virtual Environments, Human-Computer Interfaces and Measurement Systems. New York: IEEE, Inc., 2006, pp. 178-183

IEEE International Conference on Virtual Environments, Human-Computer Interfaces and Measurement-Systems (VECIMS) <4, 2006, La Coruña, Spain>

This paper presents a new approach for interactive 3D (volume) mesh manipulations based on 'on-the-fly' quality measures in order to keep the consistency of the mesh. Within pure engineering tasks, such as the analysis of physical behaviour, virtual environments only established as post processing unit, in which simulation results can be interactively displayed and visualized to get more in depth information about the simulation mock up. However, most of the simulations are done off-line which do not allow for interactive 'what-if' analysis in view of a change of the primary design domain. As design changes of the underlying CAx/FE models usually imply many manual interferences, repair and efforts (re-meshing tasks, grid repair, etc.) in order to guarantee elements of high quality during re-meshing or mesh refinement tasks, an evaluation within virtual environments is not suitable with current techniques. Thus this paper aims at introducing our approach in order to change 3D volumetric meshes on the fly and keep the consistency of the newly generated mesh in view of engineering analysis.

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Binotto, A.; Brunetti, Gino; Gierlinger, Thomas; Pereira, Carlos Eduardo; Santos, Pedro; Stork, André

Computer Graphics Applications in Virtual Engineering

2006

Ecole Supérieure des Technologies Industrielles Avancées (ESTIA): Virtual Concept : VC Preliminary Forums Summer School, 13 p.

Virtual Concept Summer School (VC SS) <2006, Porto Alegre, Brazil>

The application of computer graphics and communication technology in the product development process leads to virtual engineering that, besides Computer-Aided Design/Engineering (CAD/CAE) and Product Lifecycle Management (PLM), is becoming a key factor for successful multidisciplinary rapid product development. Virtual engineering tools address the support of cross-domain engineering to integrate the different engineering disciplines and provide a fruitful environment for innovation in products and processes. The advances in virtual engineering are motivated by the global economic competitiveness and, at the same time, by the global alliances built to meet this competition with innovation, collaboration, excellence, quality and shorter development times. In this work, the authors give an overview of the basic concepts of collaborative virtual engineering present in all phases of innovative product development (from design, to engineering, and to maintenance), providing examples for virtual engineering applications and focusing on the importance of real-time graphics systems.

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Brunetti, Gino; Schneider, Pascal; Stork, André

Constraint-Based Virtual Conceptual Design

2006

Fischer, Xavier (Ed.) et al.: Research in Interactive Design : Proceedings of Virtual Concept 2005. Paris, Berlin, Heidelberg: Springer, 2006, 8 p.

Virtual Concept <2005, Biarritz, France>

The paper introduces an approach towards modeling and validation of mechanisms in the conceptual design phase applying virtual reality techniques and kinematics simulation. The presented system allows to interactively assemble mechanisms and to experience its behavior within the same process. The described approach incrementally builds kinematic chains reducing stepwise degrees of freedom. Kinematics is expressed in terms of geometric constraints, which are solved in real-time during interaction with the virtual prototype.

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Wundrak, Stefan; Henn, Thomas; Stork, André

Dynamic Progressive Triangle-Quadrilateral Meshes

2006

Jorge, Joaquim (Ed.) et al.: WSCG 2006. Short Papers Proceedings. Plzen: University of West Bohemia, 2006, pp. 61-68

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG) <14, 2006, Plzen, Czech Republic>

We present an extension of the original progressive mesh algorithm for large dynamic meshes that contain a mix of triangle and quadrilateral elements. The demand for this extension comes from the visualisation of dynamic finite element simulations, such as car crashes or metal sheet punch operations. These methods use meshes, which consist mainly of quadrilaterals, due to their increased numerical stability during the simulation. Furthermore, these meshes have a dynamic geometry with about 25 to 100 animation steps. Accordingly, we extend the original progressive mesh algorithm in two aspects: First, the edge collapse operation is extended for meshes with a mixture of triangle and quadrilateral elements. Second, we present an algorithm on how to extend quadric error metrics for the simplification of large dynamic meshes with many animation steps. The results are dynamic progressive triangle-quadrilateral meshes - a progressive multi-resolution mesh structure that has two interactive degrees of freedom: simulation time and mesh resolution. We show that our method works on meshes with up to one million vertices and 25 animation steps. We measure the approximation error and compare the results to other algorithms.

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Brunetti, Gino; Ucelli, Giuliana; Santos, Pedro; Amicis, Raffaele de; Stork, André

Handling Shape Semantics in Virtual Styling

2006

Fischer, Xavier (Ed.) et al.: Research in Interactive Design : Proceedings of Virtual Concept 2005. Paris, Berlin, Heidelberg: Springer, 2006, 10 p.

Virtual Concept <2005, Biarritz, France>

Multimedia content and 3D models play an important role in many industrial applications. Therefore semantic processing for the purposes of comparing, cataloging and archiving 2D and 3D shapes is a major concern. Existing Konwledge Management systems fail to provide effective solutions for industrial designers and privilege the management of text-based content. In this paper we describe a content retrieval system for the styling department. Our solution provides a platform for creating, managing and retrieving semantic meta-data descriptions of multimedia content and 3D shapes using the MPEG 7 ISO/IEC standard. We further outline the rational for integrating such a solution with a virtual styling system and discuss multimodal approaches for the input of semantic metadata in virtual environments.

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Stork, André

Highlights in Current Research: Event Special

2006

Technische Universität Darmstadt (TUD): PACE. Proceedings : Partners for the Advancement of Collaborative Engineering Education. Darmstadt, 2006, pp. 237-239

International PACE Forum on Collaborative Visualization <2006, Darmstadt, Germany>

The talk gives an overview about IGD's history and current activities in research and development in the field of computer supported collaborative work (CSCW). IGD started to work in the field of CSCW 15 years ago, beginning with document sharing and white board applications. Soon, IGD started to perform research on how to share 3D documents, such as CAD models. The HP Shared 3D Viewer was one of the first products supporting collaboration with 3D CAD models in the mid 90ies. Enabling distributed VR and supporting mobile users in collaborative scenarios were the next steps along the path. Technologies such as 3D graphics compression and encoding are only one of the core techniques developed to enable collaboration with 3D graphics. Today, we see the challenges in CSCW more in the area of cross domain enginering and integration and keeping the semantics along the process.

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Stork, André; Santos, Pedro; Gierlinger, Thomas; Pagani, Alain; Paloc, Céline; Barandiarán, Iñigo; Conti, Giuseppe; Amicis, Raffaele de; Witzel, Martin; Machui, Oliver; Jiménez, José Manuel; Araújo, Bruno; Jorge, Joaquim; Bodammer, Georg

IMPROVE: An Innovative Application for Collaborative Mobile Mixed Reality Design Review

2006

Fischer, Xavier (Ed.) et al.: Research in Interactive Design. Volume 2. Proceedings : Proceedings of the Virtual Concept 2006. Paris, Berlin, Heidelberg: Springer, 2006, 11 p.

Virtual Concept <2006, Cancùn, Mexico>

In this paper we introduce an innovative application aiming at combining large, tablet-based and headmounted displays for collaborative mobile mixed reality design reviews. Our research and development is motivated by two use scenarios: automotive and architectural design review involving real users from Page\Park architects and Elasis FIAT. Our activities are supported by the EU IST project IMPROVE. It covers activities in the areas of: HMD development using unique OLED technology, markerless tracking, augmented reality rendering, image calibration for large tiled displays, collaborative tablet-based and projection wall oriented interaction and stereoscopic video streaming for mobile users. The paper gives an overview of the hardware and software developments within IMPROVE and concludes with results from first user test.

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Toro, Carlos; Posada, Jorge; Wundrak, Stefan; Stork, André

Improving Virtual Reality Applications in CAD through Semantics

2006

International Journal of Virtual Reality, Vol.5 (2006), 4, 8 p.

In this article we propose an architecture for the inclusion and exploitation of semantic aspects in a CAD environment. Our schema focuses on the enhancement and improvement of a commercial (general purpose) CAD system on its Virtual Reality (VR) capabilities. There is a need in combining CAD and semantics in the new generation of computer assisted engineering systems. Usually semantic aspects in traditional CAD applications relay on user tacit knowledge, a fact that slows the learning curve while the user is getting trained with a new tool, no matter if he is an expert in others. Moreover, current CAD programs offer a myriad of options to the designer, but their limited integration of the non geometric information (e.g. PDM systems), and in general the semantics of the design process, can still be improved for the current needs of the industry. We argue that the use of semantics could improve the workflow and capabilities of the software and would benefit a new (non experienced user) in order to produce better results in shorter times. In this paper our main focus is the enhancement of the visualization and VR capabilities in generic CAD applications. Our semantic CAD framework uses ontology modelling as well as engineering standards in order to conceptualize and exploit the information contained in a CAD model. To show some benefits of our proposed schema, we present two cases in different engineering domains (plant design and Steel detailing design), where the inclusion of semantics empowers a VR experience.

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Santos, Pedro; Stork, André; Buaes, Alexandre; Jorge, Joaquim

Innovative Geometric Pose Reconstruction for Marker-based Single Camera Tracking

2006

ACM SIGGRAPH: VRCIA 2006. Proceedings : ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications. New York: ACM, 2006, pp. 237-244

ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications (VRCIA) <2, 2006, Hong Kong>

Mobile augmented reality applications are in need of tracking systems which can be wearable and do not cause a high processing load, while still offering reasonable performance, robustness and accuracy. The motivation to develop yet another tracking algorithm is two-fold. Most of the existing approaches use classical optimization techniques such as the Gauss-Newton method. However, since those algorithms were developed to address general optimization problems, they do not fully exploit the structure of the pose estimation problem with its geometric constraint targets. Also, mixed reality applications demand that pose estimation be not only accurate but also robust and computationally efficient. Hence there is a need for algorithms that are as accurate as classical algorithms, yet are also globally convergent and fast enough for real-time applications. In this paper we introduce a new iterative geometric method for pose estimation from four co-planar points and we present the current status of PTrack, an infrared marker-based single camera tracking system benefiting from this approach. Our novel pose estimation algorithm identifies possible labels composed of retro-reflective markers in a 2D post-processing using a divide-and-conquer strategy to segment the camera's image space and attempts an iterative geometric 3D reconstruction of position and orientation in camera space. Tracking results are made available to applications through OpenTracker [OpenTracker 2006] framework. To analyse tracking accuracy and precision, we built a generic test-bed and compared PTrack to ARToolKit [Kato and Billinghurst 1999; Kato et al. 2000], one of the most wide-spread low-cost tracking solutions. Results show that our tracking system achieves competitive accuracy levels better than ARToolKit and close to commercial systems, while being highly stable and affordable.

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Santos, Pedro; Stork, André; Buaes, Alexandre; Jorge, Joaquim

PTrack: Introducing a Novel Iterative Geometric Pose Estimation for a Marker-based Single Camera Tracking System

2006

Fröhlich, Bernd (Ed.) et al.: IEEE Virtual Reality 2006. Proceedings. Los Alamitos, Calif.: IEEE Computer Society, 2006, pp. 143-150

IEEE Virtual Reality Conference (VR) <13, 2006, Alexandria, Virginia, USA>

Inside-out tracking for augmented reality applications continues to present a challenge in terms of performance, robustness and accuracy. In particular mobile augmented reality applications are in need of tracking systems which can be wearable and do not cause a high processing load. In this paper we introduce a novel iterative geometric method for pose estimation from four co-planar points and we present the current status of PTrack, a marker-based single camera tracking system benefiting from this approach. The system uses an IDS uEye [1] camera, equipped with infrared flash strobes and infrared pass filter, which acquires grayscale images and sends them to a computer where an image pre-processing algorithm identifies potential projections of retro-reflective markers. Our novel pose estimation algorithm identifies possible labels composed of markers in a 2D post-processing using a divide-and-conquer strategy to segment the camera's image space and attempts an iterative geometric 3D reconstruction of position and orientation in camera space. In the end successfully reconstructed labels are compared to a database for identification. Their 6 DoF data as well as their ID is made available to applications through OpenTracker [2] framework. To assess the performance of our approach we compared PTrack to ARToolKit [3] - which has been adapted to work with the same camera - and final results show that pose estimation is more accurate and precise, in both translation and rotation.

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Stork, André; Wundrak, Stefan; Henn, Thomas; Hietel, Dietmar; Thole, Clemens-August; Nikitina, Lialia

Simulierte Realität: Neue Ansätze in der interaktiven Visualisierung

2006

CAD-CAM REPORT, Vol.25 (2006), 12, pp. 50-54

Simulation ist heute integraler Bestandteil der virtuellen Produktentwicklung. Die Aufgabe von Simulation besteht hauptsächlich im Lösen von physikalisch-basierten Modellen in Form von gewöhnlichen und partiellen Differentialgleichungen. Aus Sicht der Produktentwicklung gilt das eigentliche Interesse der Optimierung, die Simulation ist »nur« ein Mittel zum Zweck. Die Optimierung fragt nach einem bestmöglichen Produkt im Hinblick auf vielfältige Zielkriterien (multikriterielle Optimierung), zum Beispiel Gewicht, Verbrauch und Kosten, während eine Simulation für eine konkrete Ausprägung eines virtuellen Produktes - eine Parametrisierung - die Zielgraderfüllung für ein oder mehrere Kriterien liefert.

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Posada, Jorge; Toro, Carlos; Wundrak, Stefan; Stork, André

Using Ontologies and STEP Standards for the Semantic Simplification of CAD Models in Different Engineering Domains

2006

Applied Ontology, Vol.1 (2006), 3-4, pp. 263-279

We present in this article an Ontology based compression system that uses STEP compliant standards for the compression and design review visualization of large CAD data sets. Our approach is orthogonal to the traditional techniques applied in the field as we complement previous works introducing semantic criteria along with algorithms for the categorization, simplification and user-oriented adaptation of the engineering components described by domain specific standards. As an example we have implemented two test cases in two specific domains -ISO-STEP 13013-AP227 in the case of industrial Plant Design and CIS/2 in the case of Steel Detailing Design (Structures Design).

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Santos, Pedro; Wundrak, Stefan; Stork, André

2D/3D-Interaktion im Produktentwicklungsprozess

2005

CAD-CAM REPORT, Vol.24 (2005), 7, pp. 28-31

VR Systeme sind aus dem heutigen Produktentwicklungsprozess nicht mehr wegzudenken. Trotz vieler Vorteile die mit diesen Technologien verbunden sind, sind sie jedoch noch nicht in der Lage, traditionelle Desktop Systeme zu verdrängen. Ein nicht unwesentlicher Faktor ist der hohe Investitionsaufwand, der immernoch mit dieser Technologie verbunden ist, insbesondere für die dafür notwendige Hardware. Ein weiterer Faktor ist die Gestaltung der Benutzerschnittstellen solcher Systeme, die anfänglich nicht den veränderten Gegebenheiten Rechnung trugen. Viele VR Systeme übernahmen einfach traditionelle WIMP Schnittstellen (windows, icons, mouse, pointers) statt die Möglichkeiten von VR für neue Arten der Benutzerführung zu nutzen. Allerdings werden mittlerweile immer mehr multi-modale Interaktionstechniken entwickelt, die zum Ziel haben, die Interaktion des Benutzers mit dem VR System intuitiver zu gestalten. In diesem Artikel wird ein Überblick über verschiedene dieser neuen Interaktionstechniken gegeben.

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Stork, André; Sevilmis, Neyir; Smithers, Tim; Posada, Jorge; Pianciamore, Massimiliano; Castro, Rui; Jimenez, Iván; Marcos, Gorka; Mauri, Marco; Selvini, Paolo; Thelen, Bruno

A Semantic Web Approach to CE

2005

Pawar, Kulwant S. (Ed.) et al.: 11th International Conference on Concurrent Enterprising : Integrated Engineering of Products, Services and Organisations. Nottingham: Centre for Concurrent Enterprising, 2005, pp. 193-200

International Conference on Concurrent Enterprising (ICE) <11, 2005, Munich, Germany>

Collaboration and communication is vital for concurrent engineering and concurrent enterprises. Studies show that members of product development teams spend more and more time for communication, information and document management and have less time for the creative part. Online and off-line collaboration tools address the needs of CE but searching for information and sharing knowledge still follows the old metaphor of knowledge management, i.e. knowledge can only be shared (and accessed) when a common terminology is used. To overcome this limitation, we aim to investigate emerging Semantic Web technologies that offer new possibilities through modelling and using the domain knowledge to better support users of different disciplines to exchange information and knowledge without using the other parties terminology. This paper presents one of the first approaches to tackle information and knowledge sharing by using the latest - still emerging - Semantic Web technologies. We present the system's motivation, architecture and use examples. Furthermore we report on results from user test (done by users from Schenck Pegasus GmbH and Italdesign Giugiaro). We describe the experience that we gathered with the different Semantic Web technologies and give an outlook to future research and development needs.

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Marcos, Gorka; Smithers, Tim; Jimenez, Iván; Posada, Jorge; Stork, André; Pianciamore, Massimiliano; Castro, Rui; Di Marca, Sergio; Mauri, Marco; Selvini, Paolo; Sevilmis, Neyir; Thelen, Bruno; Zechino, Vincenzo

A Semantic Web Based Approach to Multimedia Retrieval

2005

COST 292 - Semantic Multimodal Analysis of Digital Media: CBMI 2005. [cited 6 August 2009] Available from: http://www.ing.unibs.it/~cost292/pubs/cbmi05.php, 2005, 8 p.

International Workshop on Content-Based Multimedia Indexing (CBMI) <4, 2005, Riga, Latvia>

Multimedia information retrieval is vital for, among many other fields, design and engineering processes. Studies show that members of product development teams spend more and more time for information gathering and have less and less time for the creative aspects of their work. Here the combination of the still emerging Semantic Web [1] technologies and information sources with content-based indexed multimedia offers new possibilities. This paper presents one of the first approaches to tackle the retrieval of indexed multimedia keeping the semantics all over the steps of the process. The designed architecture and the implemented system allows to take advantage of the information sources with different levels of semantic richness, which we believe will be part of the Semantic Web in the near future, making the "knowledge about the indexed multimedia information" available to the user and the computer. Furthermore, this approach has been developed in the context of real scenarios provided by two companies from the Car Design and Engineering industry, and the conclusions of this work will be also summarized.

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Santos, Pedro; Stork, André; Filipe, Rodrigo; Jorge, Joaquim

An Integrated Approach to Virtual Tape Drawing for Automotive Design

2005

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 10 p.

International Conference on Human-Computer Interaction (HCII) <11, 2005, Las Vegas, NV, USA>

The present paper describes a multimodal approach to authoring in immersive virtual environments. The technique for 3D curve input presented here is based on Taping, which is widely used in automotive design to create and modify characteristic lines of a model on a white board. Taping is used both, at design review sessions or at model creation, in which designers fasten tape to back-projections of 3D models or on clay models. Currently, this approach requires designers to make photographs of their intended changes so they can later be transferred to the 3D CAD representation of the model. This process is time-consuming and can lead to miscommunications between designers and product engineers on how certain curves are to be interpreted. SketchAR is a multimodal immersive authoring system for Virtual Environments which uses sketching and calligraphic input as its main organizing paradigms. Within SketchAR, one of the first immersive design and modeling systems, virtual tape drawing has been integrated as a two-handed multi-modal interaction technique. Using optical tracking and multimodal interactions we have achieved a gadget-free interaction technique to input three-dimensional curves in 3D. Our approach uses passive optical tracking devices for high-precision and low latency input. Menu free interaction is accomplished through a synergistic combination of hand motion tracking and speech.

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Graf, Holger; Stork, André

Bridging the Gap between CAD/CAE and VR and Incorporating Semantics into the Analysis Process

2005

ProSTEP iViP Association: ProSTEP iVip Science Days 2005 : Cross-Domain Engineering. Bobingen: Kessler Verlagsdruckerei, 2005, pp. 260-261

ProSTEP iVip Science Days <2, 2005, Darmstadt, Germany>

The numerous engineers, technicians and supportive staff taking part in the design process have an impact on the structure and the content of Computer Aided Design (CAD), Computer Aided Engineering (CAE) and other CAx tools. Bringing in different levels of knowledge within different areas they contribute to a diversity of data. Currently available software is capable of fast manipulation of an ever increasing amount of information. The representation of objects within an engineering design environment uses extensively geometric aspects, whereas physical attributes assigned to geometric parts are more important to the analysts. However, during the design and analysis process, various representations of the same objects are generated and used, i.e. geometric, technological, mechanical representations, representation for manufacture, etc. involving multiple downstream applications which have to make use of similar object representations of the same design. Especially in the CAE domain current workflow lacks of significant deficiencies resulting from data exchange or adequate model representations fit for analysis. A repair/healing of the CAD model, the removal of features which are irrelevant for the analysis or even design idealisations lead to significant manual overhead during the preparation stage of the CAE process. Thus, the process of an appropriate preparation of a data model to an adequate result is time consuming and error-prone. Estimates in classical simulation (FEA/CFD) environments assume that according to the problem more than 50% of the workload is needed for data acquisition. As soon as the model is available 90% of the time needed for an appropriate digital analysis is modeling and results evaluation. Only 10% of the workload is estimated for the execution of the simulation run. These estimates do not take into account interactive modifications of the simulation. In order to enhance the integration of CAD/CAE and VR different tools emerged in the past decade allow a semi-automated way of domain decomposition, feature based modelling, fast and efficient post processing. However, still significant work has to be done in order to achieve an efficient analysis turn around.

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Encarnação, José L.; Lukas, Uwe von; Stork, André

Cross-Domain Engineering: Innovation Fields and Perspectives for Computer Graphics

2005

ProSTEP iViP Association: ProSTEP iVip Science Days 2005 : Cross-Domain Engineering. Bobingen: Kessler Verlagsdruckerei, 2005, pp. 6-17

ProSTEP iVip Science Days <2, 2005, Darmstadt, Germany>

Cross-domain engineering is a highly multidisciplinary approach that opens the door for innovation in many industrial areas. Innovation in products and processes is a constant challenge to ensure the competitiveness of our economy. Applied research plays a major role in this context as an instrument for identifying promising technologies and preparing them for industrial use. With the application focus of cross-domain engineering as a filter, this paper illustrates innovation topics of the Fraunhofer-Gesellschaft and presents selected research work based on computer graphics technologies. Finally, the authors give an indication of future work by highlighting challenges for computer graphics in cross-domain engineering.

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Graf, Holger; Wundrak, Stefan; Göllner, Carlo Moritz; Stork, André

Hybrid Objects - A Concept for the Seamless Integration of 2D and 3D User Interfaces

2005

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 10 p.

International Conference on Human-Computer Interaction (HCII) <11, 2005, Las Vegas, NV, USA>

VR systems are nowadays established in many areas. However, even in environments where VR is widely accepted, users spend the bigger part of their time working at classic desktops with WIMP (windows, icons, menus, pointers) interfaces. When switching to a VR-Setup the user usually also switches to a different application and thus needs time to familiarize with the software. For this reason we introduce a concept of HCI that is based on 3D widgets (hybrid objects) that are designed in such a way that with no or only slight modification 2D interaction is also possible. Thus, the same application can be used in 2D as well as in 3D. Furthermore, we introduce the Hybrid Desktop, a 2D/3D desktop VR configuration that is optimal for the hybrid objects concept. Finally, we describe a user test to show that skills learned on a application running on a desktop computer can be transferred to the same application running on VR hardware due to the consistent user interface.

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Thelen, Bruno; Sevilmis, Neyir; Stork, André; Castro, Rui; Jimenez, Iván; Marcos, Gorka; Posada, Jorge; Smithers, Tim; Mauri, Marco; Pianciamore, Massimiliano; Selvini, Paolo; Zecchino, V.

Informationsmanagement auf der Basis von Semantic-Web Techniken oder ein Google für Entwickler

2005

Gesellschaft Fahrzeug- und Verkehrstechnik: Erprobung und Simulation in der Fahrzeugentwicklung : Mess- und Versuchstechnik. Düsseldorf: VDI Verlag, 2005. (VDI Berichte 1900), pp. 167-180

Erprobung und Simulation in der Fahrzeugentwicklung : Mess- und Versuchstechnik <12, 2005, Würzburg>

Eine Informationsrecherche leidet häufig an geeigneten Recherchehilfsmitteln oder der Komplexität der Recherche an sich. Die Suche einer konkreten Information anhand von Dateinamen oder dem zufälligen Vorkommen von Stichworten in Dateien ist wenig hilfreich, da die erzielbaren Treffer zu sehr dem Zufall unterliegen. Es wird die Entwicklung des Suchmaschinenprototyps WIDE vorgestellt, der die Query-Interpretation auf Semantic-Web-Techniken aufbaut und dabei Queries auf den Kontext eines Aufgabengebiets abbildet. Die Suchmaschine kann für Aufgabenfelder konfiguriert werden und ist zusätzlich in der Lage, eine Query auf verschiedene Datenquellen gleichzeitig abzubilden. Die Suchmaschine bereitet die gefundenen Ergebnisse graphisch auf und assoziiert die in der Query benutzten Begriffe mit thematisch verwandten Begriffen. Die Suchmaschine kann zur Recherche von Textdokumenten, oder Prüfstandsversuchsergebnissen in ASAM-ODS-Datenquellen genutzt werden.

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Sevilmis, Neyir; Stork, André; Smithers, Tim; Posada, Jorge; Pianciamore, Massimiliano; Castro, Rui; Jimenez, Iván; Marcos, Gorka; Mauri, Marco; Selvini, Paolo; Thelen, Bruno; Zecchino, V.

Knowledge Sharing by Information Retrieval in the Semantic Web

2005

Gómez-Pérez, Asunción (Ed.) et al.: The Semantic Web: Research and Applications. Proceedings. Berlin, Heidelberg, New York: Springer, 2005. (Lecture Notes in Computer Science (LNCS) 3532), pp. 471-485

European Semantic Web Conference (ESWC) <2, 2005, Heraklion, Greece>

Effective and efficient information retrieval, knowledge sharing and combining has become an essential part of more and more professional tasks and work flows in different kinds of projects. Our aim is to investigate the use of emerging Semantic Web technologies, tools, and standards in the support of effective information retrieval in real multi-disciplinary activities, such as innovative product design. This paper presents an approach to knowledge sharing and information support that has been developed and adopted, the information system architecture that is being developed to test both this approach, and the Semantic Web techniques that are used in its implementation, some early results, and a discussion of related work in information systems and Semantic Web techniques and tools.

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Posada, Jorge; Toro, Carlos; Wundrak, Stefan; Stork, André

Ontology Supported Semantic Simplification of Large Data Sets of Industrial Plant CAD Models for Design Review Visualization

2005

Khosla, Rajiv (Ed.) et al.: Knowledge-Based Intelligent Information and Engineering Systems. Berlin, Heidelberg, New York: Springer, 2005. (Lecture Notes in Computer Science (LNCS) 3683), pp. 184-190

International Conference on Knowledge-Based & Intelligent Information & Engineering Systems (KES) <9, 2005, Melbourne, Australia>

We present in this article a semantic compression system for design review visualization of large data sets in the domain of industrial plant design. This system introduces semantic aspects that improve traditional Computer Graphics techniques used for interactive walkthroughs. We complement previous works introducing new modules and algorithms for the automatic categorization, simplification and user-oriented adaptation of engineering components in the model, and base directly our work on a full Ontology based on international standards for product data in this domain (ISO-STEP 10303-AP227).

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Ucelli, Giuliana; Amicis, Raffaele de; Conti, Giuseppe; Brunetti, Gino; Stork, André

Shape Semantics and Content Management for Industrial Design and Virtual Styling

2005

Workshop towards Semantic Virtual Environments, pp. 127-137

Workshop towards Semantic Virtual Environments (SVE) <1, 2005, Villars, CH>

Multimedia content and 3D models play an important role in many industrial applications. Therefore semantic processing for the purposes of comparing, cataloging and archiving 2D and 3D shapes is a major concern. Existing Knowledge Management systems fail to provide effective solutions for industrial designers and privilege the management of text-based content. In this paper we describe a content retrieval system for the styling department. Our solution provides a platform for creating, managing and retrieving semantic meta-data descriptions of multimedia content and 3D shapes using the MPEG 7 ISO/IEC standard. We further outline the rational for integrating such a solution with a virtual styling system.

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Graf, Holger; Wundrak, Stefan; Stork, André

The Hybrid Desktop within Engineering Environments

2005

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 8 p.

International Conference on Human-Computer Interaction (HCII) <11, 2005, Las Vegas, NV, USA>

Especially in the area of engineering applications different requirements are imposed to the usability and acceptance of new and innovative systems. A very pragmatic approach is the seamless integration into the existing environment. This paper presents a new hybrid 2D/3D system based on virtual reality that was developed in the multidisciplinary context of engineering applications. The 'Hybrid Desktop' has been realised to integrate CAD/CAE and VR review processes (which are traditionally separated disciplines) into one working environment. Beside traditional and new 6DOF devices, innovative interaction concepts have been developed in order to address the need for a seamless integration of commercial software and virtual reality systems. The Hybrid Desktop offers a new low cost based working place based on virtual reality within the engineering context. The paper highlights the realisation of a hybrid 2D/3D environment driven by engineering needs to combine multidisciplinary applications at one working place. It furthermore describes the software architecture necessary for the realisation of an integrated working space. Engineers within the automobile, aerospace and urban planning area, have proofen the usability of our approach for an effective engineering environment.

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Graf, Holger; Wundrak, Stefan; Stork, André

Towards Desktop-based VR for Engineering Environments Driven by Autostereoscopic Technology

2005

ProSTEP iViP Association: ProSTEP iVip Science Days 2005 : Cross-Domain Engineering. Bobingen: Kessler Verlagsdruckerei, 2005, pp. 158-169

ProSTEP iVip Science Days <2, 2005, Darmstadt, Germany>

Current engineering requirements focus on the integration of different services, technologies and products. Especially within the CAD/CAE domain the different disciplines of construction and analysis are traditionally separated. An integration of the process chain being complemented by innovative technologies such as Virtual Reality (VR) is one of the challenges that is addressed in this work. We set the foundations for an integrated CAD/CAE environment covering such topics as small feature identification, interactive mesh refinement, and interactive feature dragging. Interactive 3D real-time graphics is one way to analyse and interact on the ever growing CAD/CAE data more efficiently and more intuitively. VR applications have shown its power in this respect already. However, compared to desktop systems the number of VR installations in the industry is still low. This is on the one hand due to high investment costs and space demands of typical VR hardware and on the other hand due to the users lack of acceptance for entirely new 3D user interfaces. In this work we use low-cost desktop VR systems based on autostereoscopic displays (Hybrid Desktop) together with a concept of 2D/3D interaction that promises a higher user acceptance.

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Stork, André; Santos, Pedro; Wundrak, Stefan

UI Concepts of VR Systems for Product Development

2005

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 10 p.

International Conference on Human-Computer Interaction (HCII) <11, 2005, Las Vegas, NV, USA>

VR systems are well accepted in the product development process today. However this technology does not have a broad penetration and high number of installations in comparison to desktop systems, due to the high investments in VR technology especially hardware. On the user interface side many VR systems took over ideas from traditional WIMP interfaces (windows, icons, menus, pointers) without maintaining a smooth transition for the users from desktop environments to immersive environments and vice versa. In addition a great bunch of multi modal interaction techniques have been developed to render VR interaction more intuitively. This paper discusses various user interface concepts of VR systems and their use along the product development process. We give examples for solutions and projects developed in collaboration with different companies, such as BMW, Italdesign, FIAT, Airbus.

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Posada, Jorge; Toro, Carlos; Wundrak, Stefan; Stork, André

Using Ontologies and STEP Standards for the Semantic Simplification of CAD Models in Different Engineering Domains

2005

Cristani, Matteo et al.: FOMI 2005 : Proceedings of the First International Workshop Formal Ontologies Meet Industry, 9 p.

International Workshop Formal Ontologies Meet Industry (FOMI) <1, 2005, Verona, Italy>

We present in this article an Ontology based compression system that uses STEP compliant standards for the compression and design review visualization of large CAD data sets. Our approach is orthogonal to the traditional techniques applied in the field as we complement previous works introducing semantic criteria along with algorithms for the categorization, simplification and user-oriented adaptation of the engineering components described by domain specific standards. As an example we have implemented two test cases in two specific domains -ISO-STEP 13013-AP227 in the case of industrial Plant Design and CIS/2 in the case of Steel Detailing Design (Structures Design).

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Wundrak, Stefan; Stork, André; Posada, Jorge; Toro, Carlos

Using Semantics to Improve the Compression and Interactive Visualisation of Large Plant Models

2005

Schenk, Michael (Ed.): 8. IFF-Wissenschaftstage 2005. Tagungsband : Virtual Reality and Augmented Reality zum Planen, Testen und Betreiben technischer Systeme. Magdeburg: Fraunhofer IFF, 2005, pp. 131-140

IFF-Wissenschaftstage <8, 2005, Magdeburg, Germany>

Large Model Visualisation for industrial plant review is a well researched area in Computer Graphics. The possibility to have interactive walkthroughs for these very large geometric datasets offers clear benefits as it reduces design time and allows the engineers and designers to detect potential problems in the early stages of the construction phase. A common characteristic of most LMV approaches is to work on the basis of the already tessellated CAD model by applying advanced CG techniques. No special attention is given to the fact that these models were originally composed of a defined set of repeating engineering parts that do have semantics. The semantic information about these parts is already lost during the conversion process from the CAD to the VR model, valuable information that may improve the visualisation and compression significantly. The developed techniques are included into the MiroWalk LMV walkthrough system that allows interactive walkthrough of plant models on desktop-class hardware.

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Brunetti, Gino; Schneider, Pascal; Prabhu, Poojan; Schmidt, Christopher; Stork, André

Virtual Conceptual Design of Mechanisms

2005

Pan, Yunhe (Ed.) et al.: Applicatios of Digital Techniques in Industrial Design Engineering. Proceedings. Beijing, China: International Academic Publishers, 2005, pp. 10-14

International Conference on Computer-Aided Industrial Design & Conceptual Design (CAID&CD) <6, 2005, Delft, Netherlands>

The paper introduces an approach towards modeling and validation of mechanisms in the conceptual design phase applying virtual reality techniques and kinematics simulation. The presented system allows to interactively assemble mechanisms and to experience its behavior within the same process. The described approach incrementally builds kinematic chains reducing stepwise degrees of freedom. Kinematics is expressed in terms of geometric constraints, which are solved in real-time during interaction with the virtual prototype.

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Graf, Holger; Stork, André; Bouvier, Eric; Balet, Olivier

A Hybrid 2D/3D Interaction Device Steering Distributed Hybrid Applications

2004

Institute of Electrical and Electronics Engineers (IEEE): Beyond Wand and Glove Based Interaction : IEEE VR 2004 Workshop: Participant's Edition. Los Alamitos, Calif.: IEEE Computer Society, 2004, pp. 55-59

IEEE Virtual Reality (VR) Workshop <2004, Chicago, Illinois, USA>

This paper presents a new system based on a wireless 6DOFs interaction device, which is able to combine both traditional interaction possibilities that are required by common legacy point-and-click applications, with immersive point-and-interact techniques within a virtual environment. This device, associated with both standard and stereoscopic displays connected to their respective computers, defines an innovative type of distributed platform which is directly compatible with traditional legacy applications that can be augmented with an immersive environment, enabling the user to steer and control hybrid 2D/3D environments. Those concepts are illustrated by presenting an application that we are developing in the multidisciplinary context of engineering, a typical situation in which supporting the pre-existing user's environment is mandatory for the take-up and acceptance of innovative techniques from virtual reality.

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Linaza, María Teresa; Macía, Iván; Susperregui, Ana; Carrasco, Eduardo; Mihalic, Lamir; Stork, André

Aplicación de las tecnologías de Virtual Showcase en escenarios reales: el caso del Museo San Telmo

2004

V Jornadas de Informática y Sociedad : Actas. Bilbao: Universidad de Deusto, 2004, pp. 109-116

Jornadas de Informática y Sociedad (JIS) <5, 2004, Bilbao, Spain>

El conocimiento del pasado a través del legado patrimonial, la promoción de los valores identificativos y culturales, y las actividades de reconocimiento de las diversas formas de vida y cultura son, entre otras, las aportaciones del patrimonio a la educación, y en especial, a la dinámica de nuestras comunidades. El acceso intuitivo a la información en los entornos reales es un reto para las Tecnologías de la Información y Comunicaciones (TICs). Una de las líneas de trabajo más importantes en este momento se basa en aumentar el conocimiento en entornos cotidianos más que en la creación de nuevos espacios virtuales. El objetivo fundamental de este proyecto de investigación ha consistido en el desarrollo de un demostrador para la aplicación de las nuevas tecnologías en el campo de la Realidad Virtual y Aumentada a la difusión y didáctica del patrimonio cultural de manera amigable para el usuario. Este objetivo general se ha materializado en la implementación de un prototipo innovador, el Virtual Showcase, y en la evaluación del plan interpretativo diseñado para esta ocasión. La primera utilización a escala mundial de un prototipo de Virtual Showcase en entornos museográficos se engloba dentro del contexto de la exposición FERRUM. Burdina Gipuzkoan. El hierro en Guipúzcoa, que se ha realizado en el Museo de San Telmo de Donostia-San Sebastián. Los resultados preliminares obtenidos dejan intuir algunas conclusiones, como la diferencia existente entre una aplicación en un laboratorio y en un entorno real como el museo, las características físicas que debe tener el dispositivo o el gran potencial lúdico del prototipo.

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Macía, Iván; Susperregui, Ana; Carrasco, Eduardo; Linaza, María Teresa; Mihalic, Lamir; Stork, André

Application of Virtual Showcase Technologies in Real Scenarios: The Case of San Telmo Museum

2004

Computer Graphics Society (CGS): Computer Graphics International 2004. Proceedings : CGI 2004. Los Alamitos, CA: IEEE Computer Society Press, 2004, pp. 428-435

Computer Graphics International (CGI) <21, 2004, Crete, Greece>

Intuitive access to information in real environments is a challenge for Information Society Technologies. Having this in mind, a new device for Mixed Reality applications called Virtual Showcase has been developed. It has been conceived to be used in museums and exhibitions, due to its compatibility with traditional museum showcases, offering additional information to the public by means of a simple, direct and intuitive interface. This paper presents the real implementation of a Virtual Showcase passive-stereo prototype exhibited in a museum for three months. Some preliminary results concerning the evaluation process have also been included. Although the technology seems to be promising, implementation aspects such as size should be improved.

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Fleisch, Timo; Rechel, Florian; Santos, Pedro; Stork, André

Constraint Stroke-Based Oversketching for 3D Curves

2004

Hughes, John F. (Ed.) et al.: Eurographics Workshop on Sketch-Based Interfaces and Modeling 2004 : Eurographics Symposium Proceedings. Aire-la-Ville: Eurographics Association, 2004, pp. 161-165

Eurographics Workshop on Sketch-Based Interfaces and Modeling (SBIM) <1, 2004, Grenoble, France>

In this paper we present an extended approach for stroke oversketching. The stroke oversketching technique changes a curve by redrawing parts of it. Finding the part to replace and smoothing the transition is done automatically. Our extension to oversketching constraints the change of the curve to one single side profile leaving the other side profiles of the curve unchanged. Additionally we present the advantage of using this approach in car design following the classic four-side-view drawing approach.

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Graf, Holger; Koch, Marianne; Stork, André; Barski, Olaf

Cyberstilo©. Towards an Ergonomic and Aesthetic Wireless 3D-Pen

2004

Institute of Electrical and Electronics Engineers (IEEE): Beyond Wand and Glove Based Interaction : IEEE VR 2004 Workshop: Participant's Edition. Los Alamitos, Calif.: IEEE Computer Society, 2004, pp. 51-54

IEEE Virtual Reality (VR) Workshop <2004, Chicago, Illinois, USA>

This paper presents the development of a new wireless interaction device named Cyberstilo©. Virtual environments have matured during the last decade providing sophisticated solutions for exploring and experiencing 3D space in a more intuitive and natural way. Adequate interaction devices allowed the user to manipulate objects and navigate efficiently through space although having been designed for specific application scenarios. However, with its maturity new application areas of virtual reality target at multidisciplinary fields, where cultural, aesthetical, ergonomical, technical, functional and commercial requirements are becoming more important. Especially for designers aesthetics and ergonomics play an important role during the styling phase. The Cyberstilo© was specifically designed for combining ergonomical and aesthetical characterristics of interaction devices which are missing in the state-of-the-art of interaction devices.

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Smithers, Tim; Posada, Jorge; Stork, André; Pianciamore, Massimiliano; Ferreira, Nuno; Grimm, Stephan; Jimenez, Iván; Di Marca, Sergio; Marcos, Gorka; Mauri, Marco; Selvini, Paolo; Sevilmis, Neyir; Thelen, Bruno; Zecchino, V.

Information Management and Knowledge Sharing in WIDE

2004

Hobson, Paola (Ed.): Knowledge-Based Media Analysis for Self-Adaptive and Agile Multimedia Technology : Proceedings of the European Workshop on the Integration of Knowledge, Semantics and Digital Media Technology. London: Queen Mary University, 2004, pp. 351-358

European Workshop on the Integration of Knowledge, Semantic and Digital Media Technologies (EWIMT) <2004, London, UK>

WIDE is an IST project whose aim is to investigate the use of emerging SemanticWeb technologies, tools, and standards in the support of effective knowledge sharing and information management in real multi-disciplinary activities, such as innovative product design. This paper presents the approach to knowledge sharing and information support that has been developed and adopted by the WIDE product, the information system architecture that is being developed to test both this approach, and the Semantic Web techniques that are used in its implementation, some early results from the project, and a discussion of related work in information systems and Semantic Web techniques and tools.

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Posada, Jorge; Stork, André; Wundrak, Stefan; Toro, Carlos

Semantically Controlled LMV Techniques for Plant Design Review

2004

The American Society of Mechanical Engineers (ASME): 2004 ASME Design Engineering Technical Conferences & Computers and Information in Engineering Conference. : DETC 2004 [CD-ROM]. New York: The American Society of Mechanical Engineers, 2004, 7 p.

ASME Design Engineering Technical Conferences & Computers and Information in Engineering Conference (DETC) <2004, Salt Lake City, Utah, USA>

Inspecting large industrial plants in a virtual walkthrough environment has proven to be a valuable tool in Plant Design. Many CG techniques, such as various LOD and culling methods, have been developed to visualize complex models in VR environments. These techniques decide solely based on geometric properties how to optimize the scene. In this paper we introduce the concept of semantically controlled selection of those techniques and show how semantic considerations can enhance the CAD to VR conversion process for large model visualization (LMV) walkthroughs of Plant Design models, improving the performance and adapting the visualization to the users' needs. A taxonomy, together with semantic considerations coming from the relationship between user, model, and resources is the basis to decide which rules should be applied for a specific visualization technique. By extending a LMV walkthrough system we are able to reduce the complexity of large industrial plant models by a factor of two.

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Stork, André

Simulationen begreifen

2004

wt Werkstattstechnik online, Vol.94 (2004), 1

In der modernen industriellen Produktentwicklung, aber auch bei Planungen von komplexen Prozessen oder Anlagen, ist die Simulation nicht mehr wegzudenken. Allerdings müssen die Ergebnisse visualisiert werden, damit auch die entscheidenden Erkenntnisse und Rückschlüsse gezogen werden können. Moderne Technologien wie die virtuelle oder die erweiterte Realität schaffen für Ingenieure und Konstrukteure einen einfacheren Zugang zu den wichtigen Informationen.

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Fleisch, Timo; Brunetti, Gino; Santos, Pedro; Stork, André

Stroke-Input Methods for Immersive Styling Environments

2004

Giannini, Franca (Ed.) et al.: International Conference on Shape Modeling and Applications 2004. Proceedings. Los Alamitos: IEEE Computer Society Press, 2004, pp. 275-283

International Conference on Shape Modeling and Applications (SMI) <6, 2004, Genova, Italy>

This paper introduces an immersive styling environment, which aims at closing the gap between 2D drawing and 3D modeling in the design process. The main goal of the styling system is to provide the user an easy to use interface hiding the inherent mathematic nature of CAD. Creating rough 3D sketches should literally be as intuitive as 2D sketching with pen and paper. To achieve this, the tools developed in our system benefit from the stylists' skills, acquired through training over time. This paper focuses on the stroke-input methods of our styling system. We present different techniques for creating and modifying 3D curves: stroke splitting, oversketching and taping. In addition we report on the viability of using input constraints in immersive environments to overcome inherent weaknesses.

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Benölken, Paul; Graf, Holger; Stork, André

Texture-Based Flow Visualization in Augmented and Virtual Reality Environments

2004

Skala, Vaclav (Ed.) et al.: WSCG 2004 [CD-ROM] : Full Papers, Short Papers, Posters. Plzen: University of West Bohemia, 2004, pp. 21-24

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG) <12, 2004, Plzen, Czech Republic>

Virtual and Augmented Reality allows a new way of result exploration of numerical simulations, its analysis and interpretation by immersing the user into the data sets and/or by keeping the relationship and context to the real environment. Up to date only a few approaches targeting the deployment of augmented reality during the analysis stage have been published. The handling of large data sets at interactive rates becomes a crucial bottleneck and influences the successful introduction for augmented reality solutions within this area. The data exploration using different VR based solutions have shown how to ease the understanding and interpretation of complex 3D data sets using stereoscopic presentations of vector glyphs, path-, stream, streak lines or surfaces. New texture based visualization tools emerged and conciliate a better understanding of the flow fields. In this paper we describe our approach for the integration of texture based visualization methods within a mixed reality set-up during the analysis stage by introducing a 'low cost', fully 3D interactive post processing unit for large CFD data sets.

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Santos, Pedro; Fleisch, Timo; Graf, Holger; Stork, André

3D Interactive Augmented Reality in Early Stages of Product Design

2003

Jacko, Julie A. (Ed.) et al.: HCI International 2003. Proceedings of the 10th International Conference on Human-Computer Interaction. Volume 4 : Inclusive Design in the Information Society. Mahwah, New Jersey: Lawrence Erlbaum, 2003, pp. 1203-1207

International Conference on Human-Computer Interaction (HCII) <10, 2003, Crete, Greece>

Augmented Reality (AR) allow the combination of virtual and physical models, making use of visualised objects that are displayed into the field of view of the user overlaying the physical prototype. Though being inspired by the application of VR technology, AR lacks of similar shortcomings, e.g. missing of 3D interactive modelling functionalities. Hence, AR is mainly found in the late stages of product development (e.g. maintenance, training) rather than in early stages of product design where objects have to be interactively generated or modified. New approaches in 3D interaction methods for generic 3D tasks, allow the application of AR technology in early stages of product design. This paper shows how physical and virtual prototypes could be beneficially combined in a highly 3D-interactive and generic environment, thus contributing to an improvement of this stage. It furthermore highlights first applications, e.g. 3D virtual tape drawing with a two-handed 3D interactive technique in an AR set-up, in this area.

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Amicis, Raffaele de; Fiorentino, Michele; Stork, André; Monno, Giuseppe

3D-Tape Drawing in Virtual and Augmented Reality

2003

Associazione Nazionale Disegno di Macchine (ADM): International Conference on Tools and Methods Evolution in Engineering Design. Proceedings CD-ROM : XIII ADM - XV INGEGRAF. ARPA, Università degli studi di Napoli Federico II, 2003, 6 p.

International Conference on Tools and Methods Evolution in Engineering Design <2003, Cassino - Napoli - Salerno, Italy>

The initial phases of the design of industrial products, and the sketching phase in particular, are tasks usually fulfilled without the help of specific software applications. Current research efforts have shown how the use of Virtual Reality (VR) and 3D input devices could significantly aid the initial design phases [De Amicis, 1999], providing stylists with tools that support their natural attitude towards creativity without forcing them to use complex or unnatural metaphors. This paper describes the latest state of the implementation of the SPACE DESIGN and the Sketch AR system, developed by the authors at the Fraunhofer Istitute for computer graphics at the industrial application Department, and it contributes in the definition of methodologies of interaction suitable to intuitively and interactively model free form curves and surfaces in VR. The system is based on a well-established technique for conceptualisation and description of design ideas, the tape drawing, and it revises this metaphor to adapt it to a VR and AR working environment. This research work has been inspired by Tovi Grossman [Grossman et al. 2002], but to the authors there is no known approach that tries to integrate the creation and editing phase, developed and integrated inside a VR-CAD environment, for 3D curves in free space, in such natural way, herein we see the major contribution of this paper.

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Macía, Iván; Mihalic, Lamir; Susperregui, Ana; Carrasco, Eduardo; Linaza, María Teresa; Stork, André

Application of New Interfaces in Museum Environments: The Virtual Showcase

2003

XIII Congreso Español de Informática Gráfica. Actas, pp. 361-364

Congreso Español de Informática Gráfica (CEIG) <13, 2003, Coruña, Spain>

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Garcia, Jose; Santos, Pedro; Stork, André

Co-located Multi-user Support for Cooperative Process and Production Planning

2003

Stephanidis, Constantine (Ed.): HCI International 2003. Proceedings of the 10th International Conference on Human-Computer Interaction. : Adjunct Proceedings. Heraklion: Crete University Press, 2003, pp. 175-176

International Conference on Human-Computer Interaction (HCII) <10, 2003, Crete, Greece>

Process optimization, setting up or modifying lines of production usually requires the collaboration from experts with backgrounds on different disciplines such as logistics, product development, maintenance, quality assurance, operations and human resources. Existing planning tools can only support specialists working in isolation from the planning process. Interaction is limited to one-user at a time. Modifications from other collaborators have to be integrated by every specialist after every planning meeting. In this paper we present a cooperative workplace, called KoKoBel, developed for the operative optimization of planning of production, processes and premises under an organizational and technological concept based on open software architecture. At the workplace, the participants of the planning process can discuss their ideas and collaborate to generate better solutions.

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Caputo, Francesco; Amicis, Raffaele de; Gironimo, Giuseppe di; Stork, André

Ergonomic Driven Design in Augmented Reality

2003

Caputo, Francesco (Ed.) et al.: Selected papers on Tools and Methods Evolution in Automotive Design from XIII ADM - XV INGEGRAF International Conference. Napoli: ARPA, Università degli studi di Napoli Federico II, 2003, pp. 83-93

International Conference on Tools and Methods Evolution in Engineering Design <2003, Cassino - Napoli - Salerno, Italy>

Virtual Reality (VR) technology in industrial engineering has the potential to accelerate the design process, reducing time to market and faultiness of the products. The combination of direct 3D-interaction, 3D-visualization, 3D-devices and applications makes VR the ideal technique for 3D-modeling tasks, both in conceptual design and in the detailed design phase. The coordinated efforts of the Universities of Naples and Darmstadt brought to the design of a virtual environment that allows both designers and engineers to evaluate different design solutions for interiors of vehicles. The research goal was the virtual validation of the design project starting from the first phases of the development of a new car and without building physical prototypes. More specifically this paper will demonstrate how VR techniques enhance the definition of ergonomic constraints for dashboard design. In particular Ergodesign allows the design team to take into account human factors since the first stage of automotive design.

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Benölken, Paul; Graf, Holger; Stork, André

Exploring Flow Fields in Augmented Reality Environments

2003

First Research Workshop on Augmented Virtual Reality (AVIR). Proceedings : Workshop Notes. Genf, Schweiz, 2003, p. 36-38

Research Workshop on Augmented Virtual Reality (AVIR) <1, 2003, Genf, Schweiz>

Specifically during the analysis and optimization stage within the product development process, e.g. in crash tests, structural optimization or flow simulations, VR techniques contributed to a minimum number of physical models in use and enhanced the evaluation stage. As a co-existence between virtual reality techniques and physical prototypes especially within this stage during product development will build the basis for further developments and research efforts, the adoption of augmented reality opens up new challenges to the research community. AR allows a new way of result exploration, its analysis and interpretation by keeping the relationship and context to the real environment. Up to date only a few approaches targeting the deployment of augmented reality during the analysis stage have been published. This is due to the nature of numerical simulations which burden further requirements to the usability of an AR based solution. The handling of large data sets at interactive rates becomes a crucial bottleneck and influences the successful introduction for augmented reality solutions within this area. In this paper we describe our approach for the use of AR during the analysis stage by introducing a "low cost", fully 3D interactive post processing unit for large CFD data sets around a physical mock-up.

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Grimm, Stephan; Stork, André

Informations- und Wissensmanagement basierend auf Semantic Web Technologie

2003

ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb, Vol.98 (2003), 6, pp. 287-290

In diesem Beitrag wird das WIDE-Projekt als Lösungsansatz für eine bessere Zusammenarbeit unterschiedlicher Nutzergruppen, wie z.B. Designern und Ingenieuren, sowie als Wissensmanagement und Information-Retrieval-System vorgestellt. Durch den Einsatz von Techniken aus dem Bereich des Semantic Web werden Suchanfragen, die Benutzer verschiedener Fachrichtungen unter der Verwendung unterschiedlicher Terminologien an das System richten, semantisch interpretiert und aufbereitet, sodass aus einem Pool von Informationsquellen ein möglichst relevantes Ergebnis zurückgeliefert wird.

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Wundrak, Stefan; Posada, Jorge (Betreuer); Stork, André (Betreuer)

Semantic Visualization of Large Engineering Models in a Virtual Walktrough Environment

2003

Darmstadt, TU, Diplomarbeit, 2003

Teure Konstruktionsfehler großer Fabrikanlagen lassen sich oft vermeiden indem man die Anlage noch vor der Konstruktionsphase in einer virtuellen Umgebung inspiziert. Typische Modelle komplexer Fabrikanlagen bestehen jedoch aus Millionen von Elementen und können nicht ohne weiteres auf einem Arbeitsplatzrechner visualisiert werden. In dieser Arbeit wird gezeigt, dass die Miteinbeziehung von Semantik und Benutzerwissen die Qualität und Geschwindigkeit einer Echtzeit-Visualisierung verbessern kann. In dem erweiterten Walkthrough-System MiroWalk werden, basierend auf semantische Kriterien, automatisch verschiedene Visualisierungstechniken eingesetzt: Für einen bestimmten Visualisierungskontext wird ein maßgeschneidertes Modell erzeugt. Insbesondere werden wiederholt auftretende Elemente des CAD-Modells identifiziert und die resultierende semantische Information eingesetzt, um die Render-Komplexität des Modells zu reduzieren. Unter anderem werden komplexe Teile des Modells durch einfachere 3D-Symbole ersetzt

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Stork, André

Virtuelle Freiformflächenmodellierung in realen Umgebungen

2003

ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb, Vol.98 (2003), 6, pp. 300-302

Gerade im Bereich von Styling und Design sind Werkzeuge für das schnelle Entwerfen von Formen gefragt, da viele Designer CAS-Systeme noch nicht hinreichend intuitiv empfinden und die Bedienung lieber CAS-Systemspezialisten überlassen. Da jedoch 3D-Objekte das Formverständnis erleichtern, werden Werkzeuge zur schnellen Erstellung von Stylingmodellen benötigt, um nicht nur den Prozess, sondern auch die interne Kommunikation zu beschleunigen. Dieser Beitrag gibt einen Überblick über die Weiterentwicklungsmöglichkeiten der Virtuellen Realität in Richtung generative Virtuelle Umgebungen anhand von SketchAR, einer aktuellen Entwicklung am Fraunhofer IGD in Darmstadt.

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Graf, Holger; Brunetti, Gino; Stork, André

A Methodology Supporting the Preparation of 3D-CAD Data for Design Reviews in VR

2002

Marjanovic, Dorian (Ed.): Proceedings of the 7th International Design Conference. Zagreb: Faculty of Mecanical Engineering and Naval Architecture, University of Zagreb, 2002, pp. 489-495

International Design Conference (DESIGN) <7, 2002, Dubrovnik, Croatia>

In recent years a range of different VR applications have been developed for the purposes of design review and analysis. The typical data source for a design review of complex models using VR technologies is an underlying 3D-CAD system or 3D styling tool, that provides geometric and topological information of the digital model. The time to adequately prepare 3D-CAD data for a design review session using VR is inherently influenced by the underlying methodology of product modelling, data acquisition, the quality of the conversion and complexity of the digital model. To manually prepare the data without an automated mechanism is tedious and cumbersome. Thus, we describe an efficient methodology and architecture to automate the process of data preparation for the purposes of a design review session in VR.

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Graf, Holger; Santos, Pedro; Stork, André

Augmented Prototyping - Combining Physical and Virtual Prototypes Advantageously/ Beneficially

2002

Meyer, Rudolf et al.: Euro-uRapid 2002. International User's Conference on Rapid Prototyping & Rapid Tooling & Rapid Manufacturing. Proceedings : High Tech Solutions and Concepts. Frankfurt/Main, 2002, B-1/2, 7 p.

International User's Conference on Rapid Prototyping & Rapid Tooling & Rapid Manufacturing (uRapid) <2002, Frankfurt/Main, Germany>

Immersive real-time visualisation of complex product models has been widely used within the engineering domain. In recent years a range of different VR applications have been developed for the purposes of design review and analysis. The development of virtual reality techniques lead to a significant reduction of physical models though not replacing them completely within the product development process. Specifically during the analysis and optimisation stage, e.g. in crash tests, structural optimisation, VR techniques contributed to a minimum number of physical models in use. A complete replacement of physical prototypes with its virtual counterpart though, will not be possible within the near future. Hence, a co-existence between virtual reality techniques and physical prototypes in different application areas during the development process will build the basis for further developments. This paper shows how physical and virtual prototypes could be beneficially combined, thus contributing to an improvement of the rapid product development (Augmented Prototyping).

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Graf, Holger; Brunetti, Gino; Stork, André

CAD2VR or How to Efficiently Integrate VR into the Product Development Process

2002

Stelzer, Ralph H. (Ed.) et al.: CAD 2002. Proceedings : Corporate Engineering Research. Bonn: GI, 2002, pp. 249-258

CAD <2002, Dresden>

Immersive real-time visualisation of complex product models has become widely used for design review within the engineering domain. In recent years a range of different VR applications have been developed for the purposes of design review and analysis. The typical data source for a review session of complex models using VR technologies is an underlying 3D-CAD system or 3D styling tool, that provides geometric and topological information of the digital model. Most of the CAD models contain digital information which is redundnt for the purposes of a VR environment. Neverthelless, the pre-processing and data preparation step is time consuming and error prone. Tedious manual data preparation and correction is still widespread and seek sfficient mecanis to automate the turn around cycles of CAD to VR sessions. Hence, we describe an efficient methodology and architecture to automate the process of data preparation for the purposes of a design review in VR.

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Kirste, Thomas; Diener, Holger; Encarnação, L. Miguel; Hein, Oliver; Stork, André; Bimber, Oliver

Die Zukunft interaktiver Systeme: Herausforderungen an die Usability-Forschung

2002

it + ti - Informationstechnik und Technische Informatik, (2002), 1, pp. 40-48

Weltweit wird an der Entwicklung von Technologien für zukünftige interaktive Systeme gearbeitet, die neue Möglichkeiten bieten, Usability-Probleme zu adressieren. In diesem Beitrag werden einige aktuelle Forschungsansätze des Fraunhofer-Instituts für Graphische Datenverarbeitung zu kontinuierlichen und nichtsymbolischen Interaktionsparadigmen vorgestellt und ihre Auswirkungen auf die Usability-Forschung diskutiert. An konkreten Projekten werden neue Herausforderungen an die Usability-Forschung dargestellt, neuartige Lösungen für Usability-Probleme erläutert und neue Werkzeuge und Frameworks für die Unterstützung des Usability Engineerings vorgestellt.

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Benölken, Paul; Stork, André

Geometry Compression for Collaborative CAD Applications

2002

Stelzer, Ralph H. (Ed.) et al.: CAD 2002. Proceedings : Corporate Engineering Research. Bonn: GI, 2002, pp. 121-129

CAD <2002, Dresden>

In this paper we discuss the requirements of common distributed CAD applications for an efficient and complete compression and decompression of 3D models. We give an overview of the state of the art methods in the field of geometric compression and present our solution, which combines and extens two existing approaches. Finally we present the results we obtained with our implementation and discuss the experience we made with different compression schemes.

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Stork, André; Bimber, Oliver; Amicis, Raffaele de

Projection-based Augmented Reality in Engineering Applications

2002

Stelzer, Ralph H. (Ed.) et al.: CAD 2002. Proceedings : Corporate Engineering Research. Bonn: GI, 2002, pp. 241-248

CAD <2002, Dresden>

Augmented Reality (AR) superimposes computer-generated graphics onto the user's view of the real world. Today, AR applications can occasionally be found in the late phases of the product development process (PDP), such as in training and in maintenance. Head-mounted displays (HMDs) are typically used for AR applications. HMDs still show deficiencies in terms of ergonomics and image quality. Looking at the development of VR technology, it can be stated that VR began its triumphal procession only after replacing HMDs by immersive projection technology (IPT) such as PowerWalls, CAVEs, Virtual Tables. Projection-based Augmented Reality enhances such environments towards augmented reality applications. We believe that this concept opens new application possibilities for AR

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Posada, Jorge; Larzabal, Alberto; Stork, André

Semantic-Based Parametric Control of CAD Model Conversion for Large Model Visualization in Virtual Reality

2002

Cruz-Neira, Carolina (Ed.) et al.: Virtual Concept 2002. Proceedings, pp. 38-43

Virtual Concept <2002, Biarritz, France>

CAD systems offer typically some visualization tools to have a better understanding of the model. Although these possibilities have evolved considerably, even providing 3D interactive inspection of the models in Virtual Reality (VR), many CAD systems still lack of good performance in this matter, especially when Large Models are considered. This kind of conversion from CAD format to VR typically considers two factors: the modell (size, structure, complexity...) and the resources (memory, processor, graphics...). Thus, a key factor is usually forgotten: the user. User knowledge can bring semantics to the process, and allow a better Large Model Visualization (LMV) for this purpose. In this paper we explain how semantics can help in the CAD conversion for LMV, and improve the performance of visualization in environments with restricted resources. We propose a semantic-based parametric control of the conversion process to manage how different visualization techniques are applied for a specific model.

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Amicis, Raffaele de; Santos, Pedro; Stork, André; Fiorentino, Michele

SketchAR - Sketching in Mixed Realities

2002

Gausemeier, Jürgen (Ed.) et al.: Augmented und Virtual Reality in der Produktentstehung. Paderborn: Heinz Nixdorf Institut, 2002. (HNI-Verlagsschriftenreihe 107), pp. 145-156

Paderborner Workshop Augmented & Virtual Reality in der Produktentstehung <1, 2002, Paderborn, Germany>

In diesem Beitrag stellen wir ein System zum Skizzieren in Erweiterten Realitäten vor, das für unterschiedliche Anwendungen in der Produktentwicklung, insbesondere im Bereich Styling und Design geeignet ist. Motiviert ist die Entwicklung durch die Tatsache, dass die Virtuelle Realität in der Produktentwicklung viele physikalische Prototypen zwar ersetzt hat, diese aber nicht gänzlich verdrängen konnte und zukünftig wohl auch nicht verdrängen wird. Folglich werden Techniken benötigt, um auch physikalische Prototypen mit computergenerierten Infomationen anzureichern, z.B. um in Design-Review-Sessions physikalische Prototypen mit Annotationen zu versehen, um den Diskussionsstand zu dokumentieren oder sogar mit skizzenhafter Information zu bereichern, um vorgeschlagene Änderungen in Form von Kurven und Flächen über das Modell zu skizzieren und damit allen Beteiligten sichtbar zu machen. Zu diesem Zweck wird ein Computer Aided Styling-System benötigt, das die direkte drei-dimensionale Eingabe und Augmented Reality (AR) unterstützt.

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Fiorentino, Michele; Amicis, Raffaele de; Monno, Giuseppe; Stork, André

Spacedesign: A Mixed Reality Workspace for Aesthetic Industrial Design

2002

Müller, Stefan (Ed.) et al.: IEEE and ACM International Symposium on Mixed and Augmented Reality 2002. Proceedings.. Los Alamitos, Calif.: IEEE Computer Society, 2002, pp. 86-94

IEEE and ACM International Symposium on Mixed and Augmented Reality (ISMAR) <1, 2002, Darmstadt>

Spacedesign is an innovative Mixed Reality (MR) application addressed to aesthetic design of free form curves and surfaces. It is a unique and comprehensive approach which uses task-specific configurations to support the design workflow from concept to mock-up evaluation and review. The first-phase conceptual design benefits from a workbench-like 3-D display for free hand sketching, surfacing and engineering visualization. Semitransparent stereo glasses augment the pre-production physical prototype by additional shapes, textures and annotations. Both workspaces share a common interface and allow collaboration and cooperation between different experts, who can configure the system for the specific task. A faster design workflow and CAD data consistency can be thus naturally achieved. Tests and collaborations with designers, mainly from automotive industry, are providing systematic feedback for this ongoing research. As far as the authors are concerned, there is no known similar approach that integrates the creation and editing phase of 3D curves and surfaces in Virtual and Augmented Reality (VR/AR). Herein we see the major contribution of our new application.

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Fiorentino, Michele; Amicis, Raffaele de; Stork, André; Monno, Giuseppe

Surface Design in Virtual Reality as Industrial Application

2002

Marjanovic, Dorian (Ed.): Proceedings of the 7th International Design Conference. Zagreb: Faculty of Mecanical Engineering and Naval Architecture, University of Zagreb, 2002, pp. 477-482

International Design Conference (DESIGN) <7, 2002, Dubrovnik, Croatia>

Styling and ergonomic design should be preserved along the product development process, but converting physical data to digital is usually done by others, introducing the risk is of misunderstanding and error. According to our vision, VR can offer the ideal unconstrained interface for free artistic expression and bridge the gap between creative experimentation and precise manufacturing-oriented modelling. The main contribution of this article is to present a VR-based Free-Form Surface modeller called SpaceDesign, which is seamless integrated in the manufacturing process and do not require any specific knowledge about the mathematic of the generated surfaces, because the software handles such complexity in transparent way. Spacedesign is historically based on ARCADE, from which inherits most of the functionalities related to the surfaces, but introduces many new features: a navigation tool, a improved real-time visual feedback, an enhanced algorithm for the Coons Patch tool, an interactive help, and support of industrystandard file formats. Moreover, previously made engineering models can be imported and used as a visual reference, a kind of "soft" constraint. The article is organized as follow: in the second section is presented the state of the art in VR-based free form modelling, then in the third the industrial requirements are explained. The fourth section describes the implementation of SpaceDesign, focusing on the new functionalities introduced. At the end an example of application and conclusions are provided.

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Amicis, Raffaele de; Bruno, F.; Stork, André; Luchi, M.L.

The Eraser Pen: A New Interaction Paradigm for Curve Sketching in 3D

2002

Marjanovic, Dorian (Ed.): Proceedings of the 7th International Design Conference. Zagreb: Faculty of Mecanical Engineering and Naval Architecture, University of Zagreb, 2002, pp. 465-470

International Design Conference (DESIGN) <7, 2002, Dubrovnik, Croatia>

The paper presents a direct manipulative technique called 3D-Eraser Pen. By means of this technique if the resulting polyline, curve or surface is not exactly what the designer wants, he/she can delete part of the sketch just going back and do it again and again until he/she reaches the final shape. In that way we have combined the creation and deletion process, rewriting the pencil and rubber metaphor in just one tool. The possibility to use a tool that allow the user to specify 3D curves in a very easy and natural way represents the major contribution to the paper. The combination of the semi-immersive environment with lightweight interaction devices and innovative interaction techniques facilitates intuitive free-form modeling at a Virtual Table.

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Nett, Bernhard; Becks, Andreas; Stork, André; Ritter, Arno; Herbst, Iris; Durissini, Marco; Wulf, Volker; Jarke, Matthias

Unterstützung von Anlagenplanung durch einen kooperativen Planungstisch

2002

i-com, Vol.1 (2002), 3, pp. 17-27

Roomware besitzt für kooperative Anlagenplanung ein großes Potential, wenn sie domänenspezifisch gestaltet wird. Sie muss dazu erlauben, gemeinsame Absprachen ohne hohen Bedienungsaufwand für alle Beteiligten verständlich zu visualisieren und zu dokumentieren. Im vorliegenden Papier wird vorgestellt, wie auf der Basis einer empirischen Bedarfsanalyse ein kooperativer Planungstisch für den Bereich der Anlagenplanung entwickelt wird. Es wird dabei gezeigt, wie neuartige Interaktionstechno-logien zur Unterstützung realer Anwendungsszenarien genutzt werden können.

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Koch, Brigitte; Jasnoch, Uwe; Stork, André

WIDE - Semantic Web for Design and Engineering

2002

Smari, Waleed W. (Ed.) et al.: International Conference on Information Systems and Engineering 2002. Proceedings. San Diego: Simulation Councils, Inc., 2002, pp. 23-28

International Conference on Information Systems and Engineering (ISE) <2, 2002, San Diego, CA, USA>

This paper describes a knowledge management system based on semantic Web technologies developed especially for industrial designers and engineers. It supports the product development process starting from the very early stages of the design process up to the production of a prototype. Special features of the system comprise personalized content management and ontologies for information access. The knowledge portal enables the user to get a centralized access to knowledge from the design and engineering area. Furthermore, the portal serves as a platform for communication and cooperation between design and engineering. This will contribute to the interdisciplinary transfer of knowledge in these areas which will on one hand improve the quality of products and on the other hand help to support the transfer of design into the product development process as design becomes a more and more important marketing factor.

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Bimber, Oliver; Encarnação, L. Miguel; Stork, André

A Multi-layered Architecture for Sketch-based Interaction within Virtual Environments

2001

Bowman, Doug A. et al.: Siggraph 2001. Course Notes 44. Advanced Topics in 3D User Interface Design

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH) <28, 2001, Los Angeles, CA, USA>

In this article, we describe a multi-layered architecture for sketch-based interaction within virtual environments. Our architecture consists of eight hierarchically arranged layers that are described by giving examples of how they are implemented and how they interact. Focusing on table-like projection systems (such as Virtual Tables or Responsive Workbenches) as human-centered output-devices, we show examples of how to integrate parts or all of the architecture into existing domain-specific applications - rather than realizing new general sketch applications - to make sketching an integral part of the next-generation human-computer interface.

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Posada, Jorge; Stork, André

Collaborative Virtual Assembly of Spatial Dispersed and Heterogeneous 3D CAD Models

2001

Prasad, Brian (Ed.) et al.: Proceedings of the 8th ISPE International Conference on Concurrent Engineering: Research and Applications - CE2001 : Advances in Concurrent Engineering, pp. 166 - 172

ISPE International Conference on Concurrent Engineering (CE) <8, 2001, Anaheim, CA, USA>

In a typical Concurrent Engineering scenario, users can discuss currently their 3D CAD models in Collaborative CAD environments to a certain extent, but the valuable functionality of Virtual Assembly of dispersed 3D CAD parts steming from heterogeneous systems is not well addressed yet. Users should be able to examine their models in relation to others and verify that they match properly as a powerful decision-making tool independent of any specific CAD system. We present a novel user-driven approach, based on highly intuitive sequential steps, to assembly parts of 3D CAD models using a 2D input device which is completely integrated in an environment supporting geographically dispersed and heterogeneous CAD models. Users with different skills (even non-CAD users) are enabled to assemble 3D CAD models in this scenario. Our approach overcomes the inherent difficulty of assembling 3D CAD models from different systems by using basic attributes of the model instead specific assembly schemas.

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Bimber, Oliver; Encarnação, L. Miguel; Stork, André

Nahtlose Integration von Virtueller Realität in gewohnte Arbeitsplätze

2001

Zeitschrift für Arbeitswissenschaft, Vol.55 (2001), 2, pp. 103-112

Unter Verwendung von Virtueller Realität (VR) und der damit verbundenen neuartigen Technologie, entwickeln sich computergestützte Umgebungen eindeutig zu einer Hauptkomponente von zukünftigen Arbeitsplätzen. Dank einiger technologischen Entwicklungen innerhalb der letzten Jahre, stellte sich VR als eine praktisch einsetzbare Möglichkeit für viele Anwendungsbereiche heraus. In diesem Artikel wollen wir einige Ideen, technologische Konzepte und aktuelle Forschungsergebinsse vorstellen, die eine Nahtlose Integration von VR in eine gewohnte Arbeitsumgebung ermöglichen sollen, und somit zu einer sukzessiven Wandlung dieser Umgebungen zu high-tech Arbeitsplätzen beitragen.

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Amicis, Raffaele de; Fiorentino, Michele; Stork, André

Parametric Interaction for CAD Application in Virtual Reality Environment

2001

Associazione Nazionale Disegno di Macchine (ADM): International Conference on Design Tools and Methods in Industrial Engineering. Proceedings 2001, pp. D3/43-D3/52

International Conference on Design Tools and Methods in Industrial Engineering <12, 2001, Rimini, Italy>

Traditional input-output interfaces, like mouse, keyboard and monitor are not suitable for an efficient interaction between user and software in CAD applications. On the other hand, interfaces used in virtual reality systems, like gloves and head-mounted display, could be much more effective because they allow to explore 3D-space in a more intuitive way. The development of CAD systems, based on devices commonly used in Virtual Reality should offer new characteristics that completely meet the requirements of designers. Nevertheless, even if many researches have focused their work on this topic, an efficient and precise interaction is one of the most influential limits for industrial application of VR The objective of this research is to develop modelling techniques suitable for creating and modifying geometric 3D-objects in a virtual environment realised by means of virtual reality hardware systems. The combination of VR technology with the potential offered by a CADarchitecture, enables efficient and precise modeling with 3D-input devices without needing 2D-views like in many commercial CAD systems.

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Bimber, Oliver; Stork, André; Branco, Pedro

Projection-based Augmented Engineering

2001

Smith, Michael J. (Ed.) et al.: HCI International 2001. Proceedings of the Ninth International Conference on Human-Computer Interaction. Volume 1 : Usability and Interface Design: Cognitive Engineering, Intelligent Agents and Virtual Reality. Mahwah, New Jersey: Lawrence Erlbaum, 2001, pp. 787-791

International Conference on Human-Computer Interaction (HCI) <9, 2001, New Orleans, LA, USA>

This article presents the early stages of a new projection-based Augmented Reality device. Our prototype represents a seamless combination of a whiteboard and an optical combiner merging virtual objects with the surrounding real environment. With this, we strive for an efficient and problem specific application of Augmented Reality technology within the engineering domain.

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Gomes de Sa, Antonino; Rix, Joachim; Stork, André

Virtual Prototyping a Innovative and Suitable Verification Tool for Rapid Prototyping of Assembly Processes: Assembly Process Optimisation, Virtual Prototyping Environment and Usability Tests

2001

Meyer, Rudolf et al.: uRapid 2001. International Conference on Rapid Prototyping & Rapid Tooling & Rapid Manufacturing. Proceedings : High Tech Solutions and Best Practice Concepts to Promote your Competitive Advantage and market Opportunities. Amsterdam, 2001, pp. 106 -114

International Conference on Rapid Prototyping & Rapid Tooling & Rapid Manufacturing (uRapid) <2001, Amsterdam, Netherlands>

In this paper, we propose a strategy for a new organisation of the assembly process in order to have an efficient utilisation of CAx tools and VR techniques. Furthermore, we present a Virtual Prototyping (VP) software environment that integrates CAx and VR. This environment supports the data preparation between CAD and VR, and also provides two VR applications to verify assembly tasks. The main difference between both VR applications is that one is using a simultaion system as a backbone expanded with VR interaction techniques and the second one tries to support the overall assembly process by using only various VR interaction capablilities. Finally, a user survey in an industrial field evaluates both VR applications regarding for example handling, efficiency and potential. The archived results show that VR is a suitable technology for verification of virtual assembly process. Furthermore, the VR application with a simulation system as a backbone seems to be the better way to support efficiently the assembly process.

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Encarnação, José L.; Müller, Stefan; Stork, André

Virtuelle und erweiterte Realität: Schlußfolgerungen aus einem Jahrzehnt F&E, Stand der Technik und Ausblick auf kommende Entwicklungen

2001

Fraunhofer IPK: Internationales Produktionstechnisches Kolloquium 2001. Vorträge : Unternehmenswerte durch Technologie. Berlin, 2001, pp. 143-149

Internationales Produktionstechnisches Kolloquium PTK <10, 2001, Berlin>

Vor ca. 10 Jahren etablierten sich die ersten F&E-Arbeiten im Bereich der Virtuellen Realität speziell auch in Deutschland, wobei sich die VR-Systeme inzwischen in drei Generationen aufteilen lassen. Die erste Generation der VR-Systeme (´90-´95) war geprägt durch Datenhelm und Datenhandschuh, erste System-Prototypen, sowie die breite Suche nach konkreten Anwendungen. Diese wurden ab ca. 1995 vor allem im Automobilbau gefunden und rasant weiterentwickelt. Als Resultat hat sich VR heute als wichtiges Werkzeug im Kontext der digitalen Produktentwicklung etabliert. Dennoch waren die VR-Systeme der zweiten Generation (1995-2000) vor allem durch hohe Investitionskosten (speziell High-end-Graphikcomputer) in ihrem Anwendungsspektrum noch stark eingeschränkt. Fast zeitgleich entstand ein weiterer Forschungsbereich mit dem Namen Erweiterte Realität (Augmented Reality, AR). Steht im Bereich der Produktentwicklung der Umgang mit virtuellen Daten im Vordergrund, so bietet die Überlagerung dieser Informationen mit dem realen Produkt ganz neue Möglichkeiten zur Unterstützung der Produktion und der Wartung. Auch hier stehen inzwischen die ersten Systemprototypen zur Verfügung. Wie wird also die dritte Generation der VR-Systeme, bzw. die zweite Generation der AR-Systeme aussehen? Technisch gesehen spricht vieles dafür, diese Fragen nicht losgelöst voneinander zu betrachten, sondern vielmehr, nach Paul Milgram, im Sinne eines Mixed-Reality-Kontinuums. Diese Betrachtung wird im Rahmen dieses Aufsatzes näher beleuchtet.

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Bimber, Oliver; Encarnação, L. Miguel; Stork, André

A Multi-layered Architecture for Sketch-based Interaction within Virtual Environments

2000

Computers & Graphics, Vol.24 (2000), 6, pp. 851-867

In this article, we describe a multi-layered architecture for sketch-based interaction within virtual environments. Our architecture consists of eight hierarchically arranged layers that are described by giving examples of how they are implemented and how they interact. Focusing on table-like projection systems (such as Virtual Tables or Responsive Workbenches) as human-centered output-devices, we show examples of how to integrate parts or all of the architecture into existing domain-specific applications - rather than realizing new general sketch applications - to make sketching an integral part of the next-generation human-computer interface.

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Stork, André

An Algorithm for Fast Picking and Snapping using a 3D Input Device and 3D Cursor

2000

Brunet, Pere (Ed.) et al.: Cad Tools and Algorithms for Product Design. Berlin; Heidelberg; New York: Springer, 2000, pp. 113-127

Picking and snapping are essential tasks in any interactive graphics application. In the field of VR-like CAD systems, conventional ray-picking is still widely used. The 3D input devices adopted by these systems allow for direct 3D interaction, thus to completely support 3D interaction, fast picking and snappig directly in 3D is required by those systems. An algorithm that allows fast 3D picking and real-time snapping with a 3D cursor on considerably complex, precise CAD models is being presented. The runtime behaviour of the algorithm is nearly independent of the model complexity. The algorithm gains its performance by utilizing multi-level bounding box checks and using coherence between subsequent steps to minimize the number of costly nearest point calculations. In contrast to known collision detection algorithms, e.g. I-COLLIDE, it works on the precise CAD model not only with a polyhedral representation.

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Stork, André; Amicis, Raffaele de

ARCADE/VT - a Virtual Table-centric Modeling System

2000

Virtual Reality Applications Center: Fourth International Immersive Projection Technology Workshop [CD-ROM]

International Immersive Projection Technology Workshop (IPT) <4, 2000, Ames, IA, USA>

In this paper we preset an innovative 3D modelling application which consists of our ARCADE modeling system and the Studierstube/VT toolset. Studierstube/VT provides a toolset for intuitive two-handed interaction using pad and pen at a Virtual Table and serves as a the front-end in this integrated system ARCADE/VT. ARCADE is the underlying modeling system, developed having the special requirements of CAD and 3D input as well as 3D output devices in mind. It provides modeling-specific direct 3D interaction techniques. ARCADE/VT follows the idea of Wakl-Up VR. The user can just step in front of a Virtual Table and start to model in free space, no special prerequisites are placed at the user's side.

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Stork, André; Encarnação, José L. (Betreuer); Krause, Frank-Lothar (Betreuer)

Effiziente 3D-Interaktions- und Visualisierungstechniken für benutzer-zentrierte Modellierungssysteme

2000

Darmstadt, TU, Diss., 2000

Heute werden 3D-Modellierungssysteme (3D-CAD-Systeme) hauptsächlich in Verbindung mit 2D-Ein- und -Ausgabegeräten verwendet, was zur Folge hat, daß 3D-Interaktionen aus einer Sequenz von 2D-Eingaben zusammengesetzt werden müssen. Dies erfordert eine mentale Abbildung seitens des Benutzers. CAD-Systeme sind traditionell technologie-zentriert. Alternativ bietet sich ein benutzer-zentrierter Ansatz an, den den Mensch in den Mittelpunkt stellt und ein intuitiveren und effizienteren Mensch-Maschine-Dialog ermöglicht. Benutzer-zentrierte Ansätze erfordern die Berücksichtigung der wahrnehmungs- psychologischen und motorischen Fähigkeiten sowie Einschränkungen des Menschen. Benutzer-zentrierte Systeme laden zum experimentellen Erforschen der System- eigenschaften ein. Sie sollen ein flexibles Maß an Kooperationsunterstützung sowie Immersion bieten und dem Benutzer einen unmittelbareren Umgang mit dem System ermöglichen. Übertragen auf ein Modellierungssystem bedeutet dies, daß eine integrierte Betrachtung der Anforderungen von CAD, Virtueller Realität (VR) und computer-unterstützter Zusammenarbeit (CSCW) erforderlich ist. VR-Technologie, wie z.B. 3D-Eingabegeräte, haben in der Vergangenheit ihre Intuitivität für herkömmliche Interaktionen in VR, wie Greifen und Bewegen, bereits unter Beweis gestellt. Aber 3D-Eingabegeräte sind für Modellierungs- aufgaben bislang nicht in größerem akzeptiert. Das ist darauf zurück- zuführen, daß die bislang entwickelten 3D-Interaktionstechniken die CAD-spezifischen Anforderungen, wie Präzision und Effizienz, kaum in Betracht zogen. Aus diesem Grund wurden im Rahmen der Arbeit neuartige 3D-Interaktions- techniken insbesondere für die Volumenmodellierung entwickelt, die die Reiz-Reaktions-Korrespondenz wahren, direkte Manipulationen unterstützen und Präzision sowie Effizienz bieten. Diese Interaktionstechniken wurden mit entsprechenden Visualisierungstechniken kombiniert, die die Form von Objekten und deren räumliche Relationen augenfällig darstellen. Darüber hinaus wurde eine Systemarchitektur für benutzer-zentrierte Modellierungssysteme erarbeitet, die die Anforderungen von CAD, VR und CSCW gleichermaßen erfüllt. Eine prototypische Umsetzung zeigt direkt- manipulatives, kooperatives Modellieren mit 3D-Eingabegeräten in einer verteilten virtuellen Umgebung mit unterschiedlichem Maß an Immersion. Mit den entwickelten Interaktionstechniken konnte gezeigt werden, daß 3D-Eingabegeräte auch im Konstruktionsprozeß, wo Präzision eine Kernforderung ist, Vorteile bieten können. Ein neues Interaktionsparadigma, die Topologie- basierte eingeschränkte Modifikationstechnik (TCBM) ist der Schlüssel, um Eingabegeräte mit 6 Freiheitsgraden für CAD-spezifische Modifikationen zu nutzen, die oft nur eine geringere Anzahl von Freiheitsgraden benötigen. Die TCBM nutzt die 6 Freiheitsgrade von 3D-Eingabegeräten zur nicht-modalen, gesten-basierten Interaktion. Ein flexibles Diskretisierungsschema sorgt für die im detaillierten Konstruktionsprozeß benötigte Präzision der Interaktionen. Die Kombination dieser neuen Techniken und Algorithmen ermöglicht eine effiziente und präzise geometrische Modellierung mit 3D-Eingabegeräten.

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Stork, André

Interaktive Zusammenbausimulation mittels implizit generierter Assembly-Attribute

2000

Iwainsky, Alfred: CAD 2000. Tagungsband. Kommunikation, Kooperation, Koordination : Kommunikation, Kooperation, Koordination. Bonn, 2000, pp. 437-452

GI-Fachtagung CAD <2000, Berlin>

In diesem Beitrag wird ein Ansatz vorgestellt, der Assembly-Attribute implizit generiert und im Konstruktionsprozeß verarbeitet, um basierend auf dieser Information einen späteren interaktiven Zusammenbauprozeß gezielt zu unterstützen. Im Vergleich zur Kollisionserkennung bietet er den Vorteil, auf den - im Sinne des CAD-Modells- exakten Attributen zu arbeiten und dem Benutzer eine aktive Unterstützung bei der Positionierung eines Bauteils in Einbaulage zu gewähren. Im Vergleich zum herkömmlichen Vorgehen mit Assembly-Features weist der Ansatz den Vorteil auf, daß der Konstrukteur in gewohnter Weise weiterarbeiten kann, da die für den interaktiven Zusammenbauprozeß benötigte Information automatisch generiert wird.

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Stork, André; Schimpke, Oliver; Amicis, Raffaele de

Sketching Free-Forms in Semi-Immersive Virtual Environments

2000

The American Society of Mechanical Engineers (ASME): 2000 ASME Design Engineering Technical Conferences & Computers and Information in Engineering Conference [CD-ROM]. New York: The American Society of Mechanical Engineers, 2000, File DETC2000/CIE-14589, 7 p.

ASME Design Engineering Technical Conferences & Computers and Information in Engineering Conference (DETC) <2000, Baltimore, MD, USA>

In spite of the widely used sophisticated software tools for mechanical design, serious difficulties are encountered in the styling phase of the design process when free-form surfaces (shortly free-forms) have to be modelled. In this paper we extend the ideas of Sachs' pioneering 3-Draw which allowed curve sketching in 3D space in several ways: we support the creation of NURBS surfaces (not only curves), we use a semi-immersive environment centered around a table-like stereoscopic back-projection display (also know as Virtual Table or Responsive Workbench) and we give the user an immediate preview while he sketches free-form surface. This combination of features makes our approach unique in comparison to similar systems. Some of them only work on polyhedral models and others are restricted to indirect 3D interaction with control points. Our approach follows the Walk-Up VR concept: the user can just step in front of a Virtual Table and work on his task intuitively.

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Linnert, Christoph; Encarnação, L. Miguel; Stork, André; Koch, Volker

Virtual Building Lifecycle - Giving Architects Access to the Future of Buildings by Visualizing Lifecycle Data

2000

Fruchter, Renate (Ed.): Computing in Civil and Building Engineering. Proceedings 2000. Reston: American Society of Civil Engineers, 2000, pp. 7-14

International Conference on Computing in Civil and Building Engineering (ICCCBE) <8, 2000, Stanford, USA>

Today s software for architects and civil engineers is lacking support for the evaluation and improvement of building lifecycles. Facility Management Systems and 4D-CAD try to integrate lifecycle data and make them better accessible, but miss the investigation of the development of the structure itself. Much money is inappropriately spent when materials with different life expectan-cies are combined in the wrong way and building parts are repaired or replaced too early or too late. With the methods of scientific visualization and real-time 3D-graphics these deficiencies can be eliminated. The project Virtual Building Lifecycle (short VBLC, [W-VBLC]) connects 3D geometrical information to research data such as life expectancy and emissions and to standard database information like prices. The automated visualization of critical points of the structure in the past, presence and future is a huge advantage and helps engineers to improve the duration of the lifecycle and reduce the costs.

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Knöpfle, Christian; Encarnação, José L.; Stork, André; Rettig, Alexander; Benölken, Paul

Virtuelle Realität - Perspektiven für den Einsatz in der Produktentstehung

2000

Krause, Frank-Lothar (Ed.) et al.: Innovationsforum Virtuelle Produktentstehung. Vorträge / Proceedings. Berlin, 2000, pp. 287-302

Innovationsforum Virtuelle Produktentstehung <2000, Berlin>

Virtual Reality Technologien erhalten zunehmend Einzug in den industriellen Produktentstehungsprozeß. Die Integration von VR und CAD-Systemen, die Entwicklung neuer Interaktionsmetaphern und -schnittstellen, multimodale Präsentation virtueller Umgebungen, die Verwendung moderner Kommunikationstechnologien und die Entwicklung neuer Display-Technologien erweitern die Anwendungsbereiche von VR und AR nicht nur auf die klassischen Anwendungen der Computergraphik Modellierung und Visualisierung, sondern auch auf die Bereiche Produktvalidierung, Produktions- und Service-Unterstützung und kooperatives Arbeiten.

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Likavec, Jaromir; Stork, André; Gärtner, Mathias

Collaborative Engineering in Heterogenous Network Environments

1999

Jezernik, Anton (Ed.): dmmi '99. Proceedings. Portoroz, 1999, pp. 273-283

Design to Manufacture in Modern Industry <4, 1999, Portoroz, Slovenia>

The need for a computer supported collaborative engineering environment to stay competitive has never been greater. There are two major technical challenges in computer supported group work: the communication infrastructure and the collaborative applications. The communication infrastrukture has to scale to meet bandwidth requirements and quality-of-service requirements. The applications have to enable the product development team to share, discuss and realize ideas. In this paper we show some of the applications needed to establish cooperative work. We discuss the necessary communication technology and the related problems. Finally, we present a design application facilitating distributed, simultaneous design on a common model by different users.

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Stork, André; Rix, Joachim

Combining Ergonomic and Field-of-view Analysis Using Virtual Humans

1999

Society of Manufacturing Engineers: Computer Technology Solutions for the Manufacturing Enterprise [CD-ROM]. Detroit, 1999, 10 p.

Computer Technology Solutions Conference (CTS) <1999, Detroit, MI, USA>

Today, virtual humans are used in the automotive industry especially for ergonomic analysis of a virtual car interior. However, interior design and ergomonics is only one aspect in the development process of a new car. Styling, active and passive security as well as aerodynamics also bias decisions in the development process of a new car. The visibility of the surroundings from inside a car is a major security topic. This paper shows - based on a joint project with BMW - how virtual humans can be used for combined reachability and visibility analysis and how these two topics interrelate.

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Schimpke, Oliver; Stork, André (Betreuer)

Freiformflächenmodellierung am Virtuellen Tisch

1999

Darmstadt, FH, Diplomarbeit, 1999

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Stork, André; Rix, Joachim

Globales Engineering: Über Grenzen hinweg

1999

Bänder, Bleche, Rohre, Vol.40 (1999), 7/8, pp. 40-47

Globalisierung und Wettbewerbsdruck führen in vielen Industriezweigen dazu, dass auch Ingenieursleistungen verteilt erbracht werden; Outsourcing, Virtuelle Teams und verteilte Entwicklung sind hier aktuelle Schlagworte. Doch dieser trend birgt auch Gefahren und Probleme: erschwerte Kommunikation, reduzierte Verfügbarkeit von Ansprechpersonen in anderen Zeitzonen, auf wendigere Qualitätssicherung und nicht zuletzt kulturelle Unterschiede bei den Beteiligten tragen dazu bei, dass die Kostensenkungen kompensiert werden und nicht so hoch ausfallen, wie erwartet. Wer von uns kennt nicht die Beispiele aus der Automobilindustrie, wo im Ausland gefertigte Autos in Deutschland vor der Auslieferung aufwendig nachgebessert werden müssen?

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Encarnação, L. Miguel; Stork, André; Schmalstieg, Dieter; Bimber, Oliver; Barton, Robert J.

The Virtual Table: A Future CAD Workspace

1999

Society of Manufacturing Engineers: Computer Technology Solutions for the Manufacturing Enterprise [CD-ROM]. Detroit, 1999, 13 p.

Computer Technology Solutions Conference (CTS) <1999, Detroit, MI, USA>

Although product modeling is an inherently three-dimensional task, conventional displays, keyboards and 2D mice characterize today's CAD workplaces. 3D input devices are hardly used and direct 3D interaction in virtual space does not take place. The Virtual Table (VT) is a workbench-like back projection system. Stereoscopic rendering allows models to appear as floating above the table enabling the user to grab and move them through virtual space. This raises the need for appropriate direct 3D interaction techniques, which take the specific requirements of the VT and 3D modeling into account. Although many 3D interaction techniques have evolved in VR over recent years, immersive VR is still not well accepted (nor affordable) as an environment for 3D modeling tasks. Comparatively, the Virtual Table has specific advantages as it mimics the conventional drawing board. This paper presents ongoing research and development activities which are developing interaction techniques specifically suited for 3D modeling tasks at the Virtual Table, thus moving the Virtual Table towards a well-accepted tool in the CAD workplace.

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Lukas, Uwe von; Krautstein, T.; Schultz, R.; Stork, André; Widmer, Hans-Jürgen

Einfuehrung von Telekooperationstechniken in der Produktentwicklung

1998

Anderl, Reiner (Ed.) et al.: CAD `98. Tagungsband : Tele-CAD Produktentwicklung in Netzwerken. Darmstadt, 1998. (Informatik Xpress 9), pp. 306-315

CAD <1998, Darmstadt>

Der Beitrag zeigt, wie die Kommunikation zwischen Beteiligten verschiedener Prozessschritte, die an unterschiedlichen Standorten eines Unternehmens kooperieren, durch geeignete organisatiorische und technische Massnahmen verbessert werden kann. Hierzu wurde ein dreistufiges Konzept entwickelt, das die Konstrukteure schrittweise an die neuen CSCW-Technologien heranfuehrt. Dabei kommen unterschiedliche Werkzeuge zum Einsatz, die teils kommerziell verfuegbar sind, teils aufsetzend auf einem vorhandenen CAD-System neu entwickelt wurden. Vor- und Nachteile der Alternativen werden diskutiert und die Uebertragbarkeit der Konzepte auf andere Unternehmen aufgezeigt.

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Stork, André; Lukas, Uwe von; Schultz, Ralph

Enhancing a Commercial 3D CAD System by CSCW. Functionality for Enabling Co-operative Modelling via WAN

1998

Lipkin, Harvey et al.: 1998 ASME Design Engineering Technical Conferences. 1998. CD-ROM. New York: The American Society of Mechanical Engineers, 1998, pp. DECT98/CIE-5711

ASME Design Engineering Technical Conferences (DETC) <1998, Atlanta, GA, USA>

This paper presents results from a joint project with the aim to introduce advanced Computer Supported Co-operative Work (CSCW) technology to a mid-size supplier for the automotive industry by enhancing the 3D CAD system in use by CSCW functionality and enabling distributed, synchronous, co-operative modelling over a wide area network. Beside the realization of the CSCW extension we present first exprience from practical use and a cost assessment discussing the rentability of our approach.

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Lukas, Uwe von; Stork, André

Introducing Tools for Collaborative Modelling

1998

31st International Symposium on Automative Technology and Automation ISATA 98. Proceedings., pp. 333-341

International Symposium on Automotive Technology and Automation (ISATA) <31, 1998, Düsseldorf>

This paper presents the concepts and results of introducing synchronous groupware applications into a medium sized enterprise. Two groups (product development andproduct preparation) are located 200km apart and should be supported by synchronous collaboration. A concept with three stages allowed us to introduce available tools as soon as possible while developing a customised collaborative CAD system in parallel. This innovative tool is based on a commercial CAD system and directly integrates conferencing functionality. It is designed to run via small bandwith links such as ISDN. The use of those advanced collaboration technologies can result in substantial benefits for the enterprise.

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Brunetti, Gino; Stork, André

Product-centred Intuitive 3D Interaction for Feature-based Parametric Assembly Modelling

1998

Anderl, Reiner et al.: Product Data Technology. Facing the Future : Product Data Technology. Darmstadt: ProSTEP, 1998. (Informatik Xpress 10), pp. 61-71

Feature-based parametric assembly modelling is an approach to part and assembly modelling in CAD that integrates the advantages of feature-based modelling and parametric modelling. Hence, it allows to store a high degree of product semantic. This paper presents approaches to make use of this product semantic in order to parameterise the 3D graphical interaction. The goal is to support the designer in the modelling and virtual assembly process by guiding him during the interaction. Only valid modifications that are consistent with the stored product semantic should be provided.

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Stork, André; Jasnoch, Uwe; Rix, Joachim

Virtual Reality und Kooperation als integraler Bestandteil von CAD: Eine vereinheitlichte Systemarchitektur

1998

Anderl, Reiner (Ed.) et al.: CAD `98. Tagungsband : Tele-CAD Produktentwicklung in Netzwerken. Darmstadt, 1998. (Informatik Xpress 9), pp. 34-49

CAD <1998, Darmstadt>

In der Konstruktion, der Domaene von CAD-Systemen, kommen vermehrt auch Werkzeuge zum computerunterstuetzten kooperativen Arbeiten (CSCW-Tools) und Virtual Reality (VR) Systeme zum Einsatz. Bislang werden die unterschiedlichen Aufgaben, naemlich geometrische Modellierung, Visualisierung und Kooperationsunterstuetzung, durch verschiedene Systemtypen funktional abgedeckt. Die Heterogenitaet zwischen CAD- und VR-Systemen sowie den CSCW-Werkzeugen bringt diverse Probleme mit sich. Einerseits stellt der bidirektionale Datenaustausch zwischen CAD und VR ein Problem dar, andererseits unterstuetzen uebliche CSCW-Werkzeuge nur die Kooperation an CAD-Arbeitsplaetzen und nicht auch die zwischen CAD und VR. Dieser Beitrag zeigt, wie sich die Probleme im heutigen Einsatz von CSCW-Tools und VR in CAD-Umgebungen beheben lassen. Dazu wird eine vereinheitlichte Systemarchitektur eingefuehrt, die den besonderen Anforderungen sowohl von CAD als auch von VR Rechnung traegt. Die Ergaenzung des homogenisierten CAD-VR-Systems durch einen Kommunikationsmechanismus ermoeglicht kooperatives Arbeiten zwischen gleichen oder unterschiedlichen Systeminstanzen, wobei eine Instanz entweder als Desktop- oder als immersive Anwendung konfiguriert sein kann.

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Piecha, Ralf; Kestner, Wolfgang (Betreuer); Groch, W.-D. (Betreuer); Stork, André (Betreuer)

Zweihändige Eingabe in 3D-CAD unter Berücksichtigung der Anforderungen eines Virtuellen Tisches

1998

Darmstadt, FH, Diplomarbeit, 1998

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Stork, André; Jasnoch, Uwe

A Collaborative Engineering Environment

1997

Dunson, Tonya et al.: Proceedings. TeamCAD: GVU/NIST Workshop on Collaborative Design 1997. Atlanta, Georgia: Georgia Institute of Technology, 1997, pp. 25-33

TeamCAD <1997, Atlanta, GA, USA>

The need for a computer supported collaborative engineering environment to stay competitive has never been greater. There are two major technical challenges in computer supported group work: the environment and the collaborative applications integrated in these environments. The environment has to provide some services and to take care about the consistency and availability of data. The applications have to enable the product development team to share, discuss and realize ideas. In this paper, we describe such a collaborative engineering environment. We show some of the applications needed to establish cooperative work. We discuss briefly the neccessary technology and the related problems. Finally, we present a design application facilitating distributed, simultaneous design on a common model by different users.

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Preuss, Juergen; Stork, André (Betreuer)

Binary space partitioning trees zur direkt-manipulativen Volumenmodellierung

1997

Darmstadt, TH, Diplomarbeit, 1997

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Stork, André; Maidhof, Martin

Efficient and Precise Solid Modelling using a 3D Input Device

1997

Hoffmann, Christoph Martin et al.: Proceedings of the Fourth Symposium on Solid Modelling and Applications.. New York: ACM Press, 1997, pp. 181-194

Symposium on Solid Modeling and Applications (SM) <4, 1997, Atlanta, GA, USA>

To simultaneously model 3D objects efficiently and precisely seems somewhat contradictory. Several approaches have been developed to do either inaccurate but fast 3D sketching using 2D or 3D input devices or to model precisely with conventional 2D techniques. We believe that the reason why 3D input devices have not been successful outside of imprecise sketching is due to a lack of appropriate interaction techniques that drive 3D devices to their full potential. In this paper we show how a 3D input device can be used to model both rapidly and accurately. We focus on object creation and manipulation with a 3D input device and introduce a new paradigm which we call "topological-context-based modification". This technique uses the degrees of freedom of the 3D input device advantageously and places intuitive CAD-typical modification possibilities (such as change object parameter, move a plane, rotate around edge) at the user's disposal. Thus, bridging the gap between 3D sketching and detailed design.

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Schwert, Waleri; Stork, André (Betreuer)

Evaluierung und Optimierung der 3D-Interaktions- und Visualisierungstechniken in CAD

1997

Darmstadt, FH, Diplomarbeit, 1997

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Encarnação, L. Miguel; Stork, André

Adaptionsmöglichkeiten in modernen CAD-Systemen: Bewertung, Konzeption und Realisierung

1996

Ruland, Detlev: CAD `96. Tagungsband : Verteilte und intelligente CAD-Systeme. Kaiserslautern, 1996. (Informatik Xpress 8), pp. 343-356

CAD <3, 1996, Kaiserslautern>

Die Qualitaet moderner Software und folglich deren Akzeptanz wird letztlich durch das Mass an Benutzbarkeit, das dem Anwender entgegengebracht wird, definiert. Dies gilt insbesondere fuer so komplexe Anwendungen wie CAD-Systeme und speziell fuer solche, die weite Teile des Produktlebenszyklus, von Entwurf ueber die Konstruktion bis hin zur Praesentation, unterstuetzen. Aufgrund dieses breiten Einsatzspektren muessen sie den Arbeitsweisen, Vorkenntnissen und Anwendungsaufgaben verschiedenster Benutzer benuegen. Daher wird zunehmend staerker gefordert, dass CAD-Systeme ein moeglichst hohes Mass an sinnvollen, evtl. unterschiedlichen Mechanismen zur Anpassung an diverse Benutzungskriterien und -situationen anbieten. In diesem Beitrag beschreiben wir verschiedene solcher Anpassungsmoeglichkeiten und bewerten diese hinsichtlich ihres sinnvollen Einsatzes im CAD-Bereich. Des weiteren stellen wir zwei unterschiedliche Konzepte vor, wobei eines sich mit der Konfigurierung von graphischen Benutzungsoberflaechen und das andere mit Adaptivitaet von Hilfesystemen auseinandersetzt. Schliesslich zeigen wir auf, wie sich diese generellen Konzepte moeglichst flexibel und eigenstaendig realisieren und in bereits existierende Anwendungen integrieren lassen.

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Madeira, Joaquim; Stork, André; Groß, Markus

An Approach to Computer-supported Cartooning

1996

The Visual Computer, Vol.12 (1996), 1, pp. 1-17

An approach to computer-supported cartooning is described which aims at optimizing the image-related working process by introducing comptuer-support in the drawing and painting stages of the traditional cartoon production, especially allowing the automatic coloring of a sequence of digitized images. This is achieved by using a shape matching algorithm to evaluate the similarity of image regions, and by performing an optimum region assignment to identify the corresponding ones and propagate the color information through the image sequence. In order to maintain the use of traditional drawing tools, the first step in the proposed system architecture is the processing of the scanned animators' drawings to enhance their quality and extract meaningful information. Two different system modules allow either the manual coloring of images or the computer-assisted automatic painting of an image sequence. Additional modules allow the construction of a vector representation for the images, the generation of in-betweens, and the conposing of each cartoon frame. The first stages of the system's architecture - image preprocessing, painting and vectorization - are presented. Special emphasis is given to the fundamental ideas behind the computer-assisted painting and the vectorization steps. The competitiveness of the approach, which requires no special hardware or high-performance workstation, is shown.

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Jasnoch, Uwe; Kress, Holger; Quester, Remco; Stork, André

Eine plattformuebergreifende Umgebung zur kooperativen Produktentwicklung

1996

Ruland, Detlev: CAD `96. Tagungsband : Verteilte und intelligente CAD-Systeme. Kaiserslautern, 1996. (Informatik Xpress 8), pp. 384-399

CAD <3, 1996, Kaiserslautern>

Fuer die Realisierung einer verteilten Produktentwicklung stellen die Kommunikationsdienste zwischen den beteiligten Partnern der Entwicklungsgruppe eine entscheidende Grundlage dar. Erst durch ein netzwerkbasiertes Kommunikationssystem wird es moeglich, kooperatives Arbeiten an verschiedenen Standorten zu verwirklichen. Vor dem Hintergrund einer plattformuebergreifenden Systemumgebung werden in diesem Beitrag verschiedene Ebenen der Kommunikation innerhalb der Umgebung vorgestellt und die Vorgehensweise bei der Implementierung erlaeutert. Wir unterscheiden hierbei die Ebenen der Kommunikation fuer eine verteilte Visualierung, die verteilte Datenhaltung und das grundlegende Kommunikationssystem der Systemumgebung. Den Kommunikationsmechanismus fuer die verteilte Visualisierung haben wir im Graphiksubsystem verankert, die Datenhaltung stuetzt sich auf eine objektorientierte, verteilte Datenbank ab und wird ueber standardisierte Zugriffsschnittstellen angebunden. Das grundlegende Kommunikationssystem der Systemumgebung ist durch eine hierarchische Kommunikationsarchitektur mit einer dynamischen Anzahl von Kommunikations-Servern realisiert.

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Stork, André

Interfacing to a CSG History Graph

1996

British Computer Society Display Group: CSG 96. Set-theoretic Solid Modelling Techniques and Applications : Set-theoretic Solid Modelling Techniques and Applications. Winchester, UK: Information Geometers, 1996, pp. 201-214

CSG <1996, Winchester, UK>

Der Beitrag stellt eine Generalisierung des ueblichen CSG-Bereiches, den CSG History Graph vor. Er erlaubt die Wiederverwendung von Objekten und unterstuetzt somit Variantentechnik und Versionierung. Darueber hinaus werden verschiedene Kopie-Funktionalitaeten diskutiert, die die Bildung von Klassen und deren Instanziierung ermoeglichen. Damit sind Pattern und Pittern von Pattern erzeugbar. Saemtliche Funktionalitaet ist ueber ein GUI intuitiv bedienbar.

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Stork, André; Brunetti, Gino; Vieira, Ana Sofia

Intuitive Semantically Constrained Interaction in Feature-Based Parametric Design

1996

Ruland, Detlev: CAD `96. Tagungsband : Verteilte und intelligente CAD-Systeme. Kaiserslautern, 1996. (Informatik Xpress 8), pp. 77-91

CAD <3, 1996, Kaiserslautern>

Feature-based parametric design (FbPD) is currently one of the most discussed advanced modelling techniques in CAD. Its basic idea is to enable the user to model in a higher level of abstraction, combining funcionality and design intent with geometry. Using FbPD the user works in his own terms, such as create a screw hole, make a slot, etc., instead of breaking each operation down to the geometric and mathematic level. From the semantics of a feature, the applicable set of operations is constrained, e.g. it is not valid to make a hole bigger than its surrounding solid. To check whether a given feature inter-relationship fulfils all defined constraints, constraint solving techniques are used. Constraints can either be defined intrisically by a feature or extrisically by the user, e.g. the forces applied to a feature o the system, we face the questions. In an interactive, direct manipulative feature-based modelling system, we face the questions: When to process the constraints? Should the user be allowed to create invalid models? Will such situations be rejected by the constraint solver afterwards? How can we insure valid models, decrease the number of calls to the constraint solver and still being direct manipulative? This paper presents an approach that handles the constraints in the user interface level by solving them in advance of an interaction, determining the degrees of freedom and parameterizing the appropriate interaction technique. These interaction techniques are realized by so-called manipulators, allowing intuitive direct manipulation. Limiting the supported manipulation possibilities, the user can only carry out valid modifications with respect to the constraints and no constraint solving is needed during the interaction.

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Maidhof, Martin; Stork, André (Betreuer)

Konzeption und Realisierung geeigneter Interaktionstechniken fuer CAD-Systeme mittels eines 3D-Eingabegeraetes

1996

Darmstadt, TH, Diplomarbeit, 1996

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Richter, Thoralf; Stork, André (Betreuer); Kestner, Wolfgang (Betreuer); Groch, W.-D. (Betreuer)

Konzeptionierung und Realisierung einer Erweiterung eines 3D-Modellierers zum kooperativen Arbeiten in heterogenen Umgebungen

1996

Darmstadt, TH, Diplomarbeit, 1996

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Wenzel, Gerhard; Busch, Christoph (Betreuer); Stork, André (Betreuer)

Quantitative Bestimmung und Dokumentation pathologischer Hautveraenderungen mittels eines 3D-Laserscanners und Methoden der Bildverarbeitung

1996

Darmstadt, FH, Diplomarbeit, 1996

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Madeira, Joaquim; Stork, André

Topology Preserving Vectorization

1996

Teixeira, José Carlos et al.: Modelling and Graphics in Science and Technology. Berlin; Heidelberg; New York: Springer, 1996. (Beiträge zur Graphischen Datenverarbeitung), pp. 231-243

Luso-German Computer Graphics Meeting <3, 1994, Coimbra, Portugal>

An approach to the automatic vectorization of binary raster images is presented, which combines the topology of the image contents and the shape of the image lines into a single representation. Such a representation is useful for handling the animator's drawings in computer-supported cartooning systems. Two alternative methods for the approximation of the shape of the image lines are described.

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Stork, André; Anderson, Brian

3D Interfaces in a Distributed Modelling Environment: 3D Devices, Interaction and Visualization Techniques

1995

Fellner,D.W.: Modeling - Virtual Worlds - Distributed Graphics : Beitraege zum Internationalen Workshop MDV '95. Sankt Augustin: Infix, 1995, pp. 83-92

Internationaler Workshop MVD <1995, Honnef>

Wir beschreiben das Modellierungssystem (ARCADE) sowie den "Ueberbau", der das verteilte Visualisieren und Interagieren erlaubt. Insbesondere widmen wir uns den Themen: 3D Ein-/Ausgabegeraeten, 3D Interaktions- und Visualisierungstechniken, sowie der Integration verschiedener Anwendungen durch einen verteilten Szenengraphen. Im Vordergrund der Ueberlegungen steht dabei die Desktop-Umgebung von CAD/Modellierungsarbeitsplaetzen, deren spezielle Anforderungen sowie Fragen der Akzeptanz.

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Madeira, Joaquim; Stork, André

Topology Preserving Vectorization of Scanned Images

1995

Grupo Português de Computação Gràfica (GPCG): 7ø Encontro Português de Computação Gráfica, pp. 213-227

Encontro Português de Computação Gráfica (EPCG) <7, 1995, Lisboa, Portugal>

A sequence of operations is presented which enables the computation of a topology preserving vectorial representation of a binary raster image. The image lines may have varying width and irregular borders. Two alternative methods for the approximation of the image lines using Bezier curves are discussed.

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Stork, André; Madeira, Joaquim; Groß, Markus

Computerunterstützte Zeichentrickfilmerstellung: Lösungsansätze, Methoden, Algorithmen

1994

Englert, Gabriele (Ed.) et al.: Visual Computing. Workshop-Proceedings. Darmstadt, 1994

Workshop zum Thema Visual Computing <1, 1994, Darmstadt>

Es wurde ein Loesungsansatz zur computerunterstuetzten Zeichentrickfilmerstellung vorgestellt, der Methoden aus der Bildverarbeitung und Computergraphik nutzt. Er setzt bei der traditionellen Vorgehensweise an und involviert den Benutzer und seine Interaktionen, woimmmer es sinnvoll ist, um ein Maximum an Effizienz zu erreichen, anstatt ihn zu einer radikal anderen Arbeitsweise zu zwingen. Die Vektorisierung wird weiterhin Bestandteil von Untersuchungen sein, auf ihre Basis liessen sich auch die matching-Ansaetze stellen. Die Extraction und der Aufbau hoeherwertiger Strukturinformation, insbesondere Tiefeninformation, die auf Verdeckungen hindeutet und sich aus den Zeichnungen bzw. einer Sequenz davon aehnlich wie beim "shape from motion" sowie aus der Topologie ableiten liesse, koennte dabei unterstuetzend wirken. Die vorgestellten Ergebnisse und Erfahrungen fliessen in ein kommerzielles Softwaresystem ein, das derzeit realisiert wird. Die Zielhardware wird ein PC-System der obe ren Leistungsklasse sein, was auf eine angemessene Komplexitaet der Algorithmen hindeutet. Andere Bereiche, in denen die entwickelten Methoden eingesetzt werden koennen, sind Objekterkennung, graphisches Edieren und Kolorieren von s/w-Filmen.

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Madeira, Joaquim; Stork, André

Design of a Toolbox to Assist the Cartoon Production

1994

Martins, F. Mário (Ed.) et al.: 6ø Encontro Português de Computação Gráfica. Braga: Universidade do Minho, 1994, pp.121-132

Encontro Português de Computação Gráfica (EPCG) <6, 1994, Braga, Portugal>

The production of 2D animation films (i.e. cartoons) using traditional techniques is a labor- and cost-intensive process. If some of its tasks could be efficiently supported by appropriate computer tools, production costs would certainly decrease. A set of tools to assist the painting and inbetweening stages of the traditional cartoon production is currently being developed. The reasoning behind the toolbox structure and the fundamental aspects of the developed assisted painting approach are presented.

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Madeira, Joaquim; Stork, André

Topology Preserving Vectorization

1994

CCG/ZGDV. Centro de Computacao Grafica: Graphics and Modelling in Science & Technology. Proceedings : Participants' Edition. Coimbra, 1994

Luso-German Computer Graphics Meeting <3, 1994, Coimbra, Portugal>

An approach to the automatic vectorization of binary raster images is presented, which combines the topology of the image contents and the shape of the image lines into a single representation. Such a representation is useful for handling the animator's drawings in computer-supported cartooning systems. Two alternative methods for the approximation of the shape of the image lines are described.

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Stork, André; Groß, Markus; Saradeth, S.

The Analysis of Remotely Sensed Data with Neural Networks

1992

European International Space Year Conference, ESA ISY-2. Proceedings, Munich, 1992, pp. 417-422

European International Space Year Conference <1992, Munich>

This paper describes the application of artificial neural networks (ANN) towards the supervised classification of multispectral satellite data. A direct comparison with the maximum likelihood (ML) classifier is performed. The ANN is implemented as a multilayer perceptron and trained by the backpropagation algorithm. Two Landsat Thematic Mapper scenes covering the district of Niederbayern in Germany and extensive ground truth form the basis for this approach. Confusion matrices are used to compare the results of the classification process. In addition the generalization capabilities of ANN are demonstrated. (IGD)