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.

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.

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

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.

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

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.

3D-COFORM workshop: The project aims to establish 3D documentation as an affordable, practical and effective mechanism for the documentation and visualisation of tangible cultural heritage. LINKSCEEM 2 workshop: LinkSCEEM2 aims to develop a high performance computing eco-system in the Eastern Mediterranean region by interlinking and coordinating regional compute, data and visualisation resources to form an integrated e-platform. V-must presentation: V-MusT is a new EU FP7-funded network of excellence that aims to provide the heritage sector with the tools and support to develop virtual museums that are educational, enjoyable, long-lasting and easy to maintain. The project started at the beginning of 2011.

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.

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.

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

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.

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.

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

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.

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

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.

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.

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.

The development of efficient and stable fluid simulations is a challenging task in computer graphics. Elcott et al. [6] describe an approach, based on Discrete Exterior Calculus for simulating the fluid flow. A vorticity based formulation of the incompressible Navier-Stokes equations is used, resulting in a mass-conserving representation of the velocity field by definition. This approach preserves vorticity at a discrete level, resulting in a visually more realistic fluid flow. We extend this approach to regular grids in two dimensions. So, we avoid computationally expensive mesh constructions. We discuss non-trivial boundary conditions and arbitrary topologies. The vorticity conservation properties are compared with the classical mesh based approach of Elcott et. al. We especially analyze the corresponding pressure fields near the boundaries of inner objects.

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

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.

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.

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.

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

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.

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

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.

You, S. (Organizer) et al.: Reconstruction and Modeling of Large-Scale 3D Virtual Environments : ECCV 2010 Workshop W10 [USB Stick], 14 p.

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.

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

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.

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

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).

IEEE Computer Society: 2010 IEEE International Symposium on Parallel & Distributed Processing, Workshops and Phd Forum : IPDPSW. New York: IEEE Computer Society Press, 2010, 4 p.

High-performance platforms are required by applications that use massive calculations. Actually, desktop accelerators (like the GPUs) form a powerful heterogeneous platform in conjunction with multi-core CPUs. To improve application performance on these hybrid platforms, load-balancing plays an important role to distribute workload. However, such scheduling problem faces challenges since the cost of a task at a Processing Unit (PU) is non-deterministic and depends on parameters that cannot be known a priori, like input data, online creation of tasks, scenario changing, etc. Therefore, self-adaptive computing is a potential paradigm as it can provide flexibility to explore computational resources and improve performance on different execution scenarios. This paper presents an ongoing PhD research focused on a dynamic and reconfigurable scheduling strategy based on timing profiling for desktop accelerators. Preliminary results analyze the performance of solvers for SLEs (Systems of Linear Equations) over a hybrid CPU and multi-GPU platform applied to a CFD (Computational Fluid Dynamics) application. The decision of choosing the best solver as well as its scheduling must be performed dynamically considering online parameters in order to achieve a better application performance.

B-Splines eignen sich zur Approximation von Hand eingegebener Kurven. In diesem speziellen Fall soll eine Approximation gefunden werden die möglichst nah an der eingegebenen Kurve ist, jedoch durch wenige Kontrollpunkte definiert ist. Die Approximation solch einer Kurve ist jedoch ein schwieriges Optimierungsproblem. Evolutionäre Algorithmen haben sich bei dieser Art von Optimierungsproblemen als nützlich erwiesen. Auch in anderen Arbeiten wurden schon evolutionäre Algorithmen zur Approximation mit B-Splines eingesetzt. Da die hier verwendete Repräsentation der B-Splines sehr speziell ist sind die dort verwendeten Techniken allerdings nur bedingt anwendbar. Die Approximation von Kurven durch B-Splines ebenso wie Evolutionäre Algorithmen haben viele austauschbare Komponenten, wie beispielsweise Fitnessfunktion, das Maß mit dem die Kontrollpunkte den Fehler beeinflussen, Seeding- und Evolutionsfunktionen. Um den Algorithmus erweiterbar für diese verschiedenen Möglichkeiten und auch neue Entwicklungen zu machen wird der Algorithmus in ein Framework eingebettet.

In order to accelerate the solution of linear systems, multigrid methods utilize different levels of discretizations. Transfer operations between different levels are usually straightforward, since most geometric multigrid solver is embedded in structured problem domains. However, the multigrid method in this thesis makes use of barycentric coordinates to cope with unstructured problems. Thereby, the approach is applied to a Finite Element framework simulating deformable models on both linear and quadratic tetrahedral meshes.

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.

IEEE Computer, Vol.43 (2010), 6, pp. 48-53

The literally billions of images available from online photo-sharing sites offer an unprecedented wealth of information but also add additional layers of complexity for reconstruction applications.

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

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.

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.

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.

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.

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.

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.

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.

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

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.

Khan, Azam (Ed.): 2010 Proceedings of the Symposium on Simulation for Architecture and Urban Design, pp. 129-136

This paper introduces new approaches to enable collaborative outdoor mixed reality design review in the architectural domain as well as outdoor mixed reality experiences in the cultural heritage domain. For this purpose we present the results of three closely related European projects, IMPROVE and CINeSPACE, which are currently succeeded by MAXIMUS, continuing the development of technologies relevant to the two domains. The paper focuses on the base technologies needed to develop usable outdoor mixed reality applications, such as marker-less optical tracking combined with sensor fusion for accurate pose estimation outdoors. Furthermore the paper presents a new visualization system developed within the project, one of the few daylight blocking head.-mounted displays available. In addition to pose estimation and visualization devices, the paper presents a VR framework adapted for the architecture and the cultural heritage domain featuring high dynamic range image acquisition combined with pre-computed radiance transfer rendering to be able to photo-realistically render urban content. For the cultural heritage domain this framework has been extended to allow accurate display and generation of multimedia content super-imposed on a real environment as well as city navigation.

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

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.

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.

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.

Mit der Entwicklung immer leistungsfähigerer und flexiblerer Grafikhardware können zunehmend komplexere Darstellungsalgorithmen umgesetzt werden. Zusätzlich verlangen die heute weit verbreiteten hochauflösenden Displays sehr datenintensive Inhalte. Dies führt dazu, dass die Erstellung und Akquisition von Daten für eine realistische Darstellung immer mehr an Bedeutung gewinnt. Eine besonders wichtige Rolle spielt dabei die naturgetreue Modellierung und Beleuchtung von Oberflächen. Viele Bemühungen konzentrieren sich dabei auf die Vermessung und Darstellung von Reflexionseigenschaften jedoch sind auch geometrische Aspekte der Oberflächenstruktur ausschlaggebend für die Berechnung realistischer Bilder. Zwar existieren eine Reihe von Algorithmen und Systemen zur Geometrievermessung jedoch sind diese meist nicht geeignet um feine Details ausreichend aufzulösen. Deswegen beschäftigt sich diese Arbeit mit der Entwicklung und Implementierung eines Rekonstruktionsalgorithmus für einen 3D-Scanner der unter Verwendung einer speziellen Projektorerweiterung den hohen Genauigkeitsanforderungen gerecht werden kann.

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.

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.

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

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.

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

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.

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).

Journal of Intelligent Manufacturing, Vol.20 (2009), 5, pp. 553-567. First published in Online First 27 July 2008, DOI: 10.1007/s10845-008-0151-z

Effective and efficient information management and knowledge sharing has become an essential part of more and more professional tasks in the Product Development Process. Among the various Knowledge Management technologies, ontologies offer new possibilities for representing, handling and retrieving product related knowledge, and for online collaboration.We conceived a Product Design Ontology (PDO) which especially addresses researchers in industrial product design and engineering analysis who need to share shape data and to develop software tools. In particular, we formalised the task-specific information associated to a shape, and the functionality and usage of shape processing methods in specific tasks of the design workflow. The PDO, thanks to the ontology-driven metadata on shapes and tools, may be also useful in industry on the one hand for training and for retrieving shape-related information, on the other hand for supporting benchmarking of processing tools and gathering the knowledge about shape processing workflows.

CFD computations are very important in the design process of new products that interact with fluids. But even on modern hardware, those computations are too time-consuming to be used constantly in the design process. In this work modern graphics hardware is tested in order to significantly speed up systems of linear equations computations with the goal to increase performance of CFD computations. This way, this work shows different ways of parallelizing existing algorithms (Jacobi, Gauss-Seidel, Conjugate Gradient) to be used in a GPGPU environment. The use of multiple GPUs is discussed as well as a basic rating system is introduced in order to improve load balancing between different devices.

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

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.

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

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.

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

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.

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.

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.

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

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.

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

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.

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

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.

In order to generate realistic looking images, modern methods for global illumination require detailed material representations. With the Bidirectional Texture Function (BTF) an image-based technology exists that fulfills these requirements at the expense of a high memory consumption and difficult editability. By separating a BTF in its heightfield and an analytical spatially varying Bidirectional Reflectance Distribution Function (SVBRDF) an efficient compression and good editability can be achieved, while maintaining the essential reflection characteristics. In this thesis a hybrid method using both CPU and GPU is presented to generate analytical SVBRDFs on the base of a BTF and the according heightfield. The focus is put upon an efficient work balance between both processing units, in order to speed up the fitting process significantly. For this purpose an appropriate analytical SVBRDF model has been developed. Additionally this thesis describes a hybrid, parallel working optimization process and evaluates it with the help of selected BTF datasets. Finally the results are discussed in detail. In comparison to conventional Methods, the approach presented in this work achieves a significant speedup in the optimization phase. The resulting representation consisting of SVBRDF and heightfield can additionally, in contrast to BTF data, be integrated easily in a shader-based rendering algorithm while still maintaining real-time capabilities.

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.

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.

The simulation of meshes with dynamic geometry and topology (also known as dynamic meshes) is a new and unexplored field. Recently, motivated by the challenge of developing multidisciplinary solutions for exploring design variations, such as to simultaneously design and engineer products, the scientific community has started taking interest in dynamic meshes. The traditional simulation procedure for meshes with constant topology builds a system of equations which then is solved to reveal the solution of the studied problem. The first approaches to dynamic mesh simulation reuse this procedure as many times as the number of topological changes suffered by the simulated object. In this thesis, a new approach to the simulation of dynamic meshes is presented. This methodology is different from the previous developed approaches as it avoids the systematic rebuilds of the system of equations. Instead, a methodology was developed that quickly and locally revalidates the system so that it always represents the current state of the dynamic mesh. Tests comparing the performance of the presented methodology with the previous approaches, show a significant reduction in the simulation time, achieving real-time performance for meshes with higher complexity.

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.

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.

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.

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

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.

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

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).

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.

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

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.

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

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.

This bachelor thesis targets to solve the problem of exchanging data between different 3D modeling formats, to be exact JT-file format and SAT-file format. It is motivated by the need of a tool which "knows" the structure of both formats, is able to easily translate between them and in this way helps to use the advantages of both. The way to solve the problem is to design and implement software for bridging these two well known and widely used 3D formats. However, it also deals with the closely related subjects of shape topology and shape geometry as well as the issues of compress/decompress of heavy data. The notions of topology and geometry I will explain, in detail, later on.

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

Optical motion tracking systems are widely employed in virtual- and mixed reality applications enabling users to directly interact with 3D space. Important efforts have been made to make such technologies available to a larger group of users by significantly reducing their deployment costs. In this poster we introduce the result of a German-Brazilian cooperation: The first commercial low-cost marker-based optical tracking system developed in South-America. Despite using cheaper technologies and being low-cost which usually imply worse performance and accuracy, we developed a system with sufficient accuracy for professional use.

Braz, José (Ed.) et al.: GRAPP 2008 : Proceedings of the Third International Conference on Computer Graphics Theory and Applications. Setúbal: INSTICC Press, 2008, pp. 113-118

In surface reconstruction from slice samples (typical in medical imaging, coordinate measurement machines, stereolithography, etc.) the available methods attack the geometrical and topological properties of the surface. Topological methods classify the transitions occurred in the 2-manifold between two consecutive slices i and i+1. Geometrical methods synthesize the surface based on local proximity of the contours in consecutive slices. Superimposed 2D Voronoi Diagrams VDi and VDi+1 for slices i and i+1, respectively, present topological problems if, for example, a site of VDi lies on an site or an edge of VDi+1. The usual treatment of this problem in literature is to apply a geometrical disturbance to either VDi or VDi+1, thus eliminating the degeneracy. In contrast, this article presents the implementation of a method which identifies the degenerate situation, constructs un-instantiated topological constructs, choses a geometrical instantiation based on a virtual disturbance introduced to the actual configuration. The algorithm was successfully applied to remove non-manifold topologies produced by well known algorithms in surface reconstruction

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

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.

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

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).

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.

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.

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.

In der Literaturübersicht werden die theoretische Grundlagen des Begriffs "virtuelle Realität" beschrieben. Die Begriffe "Virtual Reality" "Mixed Reality", sowie Immersion werden vorgestellt. Weiterhin werden Eingabegeräte und Darstellungsmöglichkeiten für die Interaktion im virtuellen Raum beschrieben. Zusätzlich werden einige verbreitete 3D-User-Interfaces, deren Nachteile, sowie Parallelen zu normalen Desktop-Applikationen thematisiert. Die Techniken und Programmiersprachen, die für die Umsetzung dieser Diplomarbeit zum Einsatz kamen, u.a. das VR-Framework Instantreality, sowie OpenSG und X3D werden erläutert. Einige Studien verschiedener Experten für Interface-Design werden vorgestellt, welche die Konzeption der im Anschluss beschriebenen Menü-Entwürfe beeinflussten. Es folgt eine Beschreibung der Umsetzung der Menü-Entwürfe in funktionsfähige Prototypen. Der aktuelle Stand der Literatur zum Thema Nutzertest wird kurz dargestellt. Zudem werden Entwicklung und Auswertung des durchgeführten Versuchs beschrieben. Die wichtigsten Inhalte werden abschließend zusammengefasst und ein Ausblick für weitere Forschungsansätze gegeben.

Ziel der Arbeit ist die Erstellung einer Sammlung von Leuchten- und Materialbeschreibungen, welche in der interaktiven Beleuchtungssimulation verwendet werden kann. Die Akquisition der Leuchtendaten soll auf den von Leuchtenherstellern zur Verfügung gestellten Messwerten (Eulumdat-Format/IESFormat) basieren. Diese Daten müssen in eine für das verwendete Rendering System geeignete Form (Texturen) überführt werden. Die Akquisition von Materialbeschreibungen soll auf der Basis von Photographien realer Materialien durchgeführt werden. Dabei ist eine Reihe von Bildern eines Materialmusters unter verschiedenen Beleuchtungssituationen zu erstellen. Diese Folge von Bildern muss ebenfalls in eine für das verwendete Rendering System geeignete Form (3D-Texturen) überführt werden. Die Akquisition und Nachbearbeitungsschritte sollen soweit wie möglich automatisiert werden. Am Fraunhofer Institut für Graphische Datenverarbeitung (IGD) wird ein Softwaresystem entwickelt, welches die interaktive Lichtsimulation ermöglichen soll. Dabei sollen die Objekte der Szenen interaktiv bewegt und das Simulationsergebnis möglichst realistisch in Echtzeit dargestellt werden können. Es sollen Bilder generiert werden, keine numerischen Größen (Lichtstärkewerte) die als Zahlen auf einem Raster dargestellt sind. Ein solches Raster ist für den Nutzer nicht intuitiv. Es soll ein möglichst photorealistisches Bild generiert werden, mit dem gearbeitet werden kann. Ein Verfahren zur Generierung qualitativ hochwertiger Echtzeitzeitbilder ist PRT (Precomputed Radiance Transfer). Dieses Vorgehen hat gegenüber den klassischen Real-Time-Rendering-Verfahren, wie z.B. OpenGL den Vorteil, dass Flächenlichtquellen und somit weiche Schatten in Echtzeit simuliert werden können. Precomputed Shadow Fields [11] erweitert PRT um dynamische Objekte und lokale Lichtquellen. Allerdings ist hier keine indirekte Beleuchtung in dynamischen Szenen möglich. Das System, welches das IGD benutzt und weiterentwickelt, erweitert die Shadow Fields um indirekte Beleuchtung. Das Besondere an dem neuen System soll nun sein, dass diese Methoden des dynamischen PRT für das Lichtdesign nutzbar gemacht werden. Hierfür sind entsprechende Eingangsdaten (Licht- und Materialdefinitionen) notwendig, um die Lichtsimulation auszuführen. Physikalisch basierte Daten bereitzustellen ist Ziel des Projektes.

German e-Science Conference 2007. Proceedings. [cited 13 July 2007] Available from: http://edoc.mpg.de/display.epl?col=100&grp=1414 2007, 10 p.

At first glance, it seems to be quite surprising that so far traditional business process-oriented knowledge management techniques have not been transferred to research in order to improve the efficiency of scientific work on a larger scale. But due to the high variability and unpredictability of scientific work processes, these techniques are not applicable. In fact scientific work processes have to be understood as a network of informal learning processes with a high level of social in-teraction. For this purpose, we have elaborated the model of a "Knowledge-Added Process" as a new paradigm of process-oriented support. We are developing various models, methods, and tools on the basis of semantic technologies supporting this process, and which are exemplified within three scenarios within the application domain "rapid prototyping".

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.

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.

Diese Bachelorarbeit beschäftigt sich damit, Modelle der Automobilindustrie visuell abzubilden, um den Produktentwicklungsprozess virtuell zu unterstützen und zu beschleunigen. Die bildliche Wiedergabe der Informationen wird dabei durch die Zusammensetzung einer sehr großen Menge von Polygonen realisiert. Es werden ausführlich die Merkmale polygonaler Netze zur grafischen Datenverarbeitung beschrieben. Besonders hervorgehoben wird hierbei die Systematik, eine Netzstruktur progressiv aufzubauen. Dadurch wird es ermöglicht, große und komplexe Modelle vereinfacht wiederzugeben. Bei der Betrachtung der verschiedenen Bestandteile einer Simulation, besitzen dynamische Simulationsergebnisse auf Grund des zusätzlichen Zeitfaktors mit knapp 90% Anteil den mit Abstand größten Speicherbedarf. Deshalb sind Funktionen für eine kompaktere Darstellungsform dieser dynamischen Eigenschaften integriert worden. Eine Leseroutine wurde entsprechend angepasst. Um einen frühen Visualisierungsprozess des progressiven Netzaufbaus zu ermöglichen, ist der Prototyp einer neuen Leseroutine auf Basis der Beschreibungssprache XML entwickelt worden. Der Lesevorgang kann für eine ausreichend detaillierte Visualisierung oder bei einer langsamen Datenübertragung nach jedem Block gelesener Elemente unterbrochen werden.

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

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.

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

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.

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

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.

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

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.

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

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.

Gobbetti, E. (Ed.): Proceedings of the Ninth IASTED International Conference Computer Graphics and Imaging [CD-ROM]. Anaheim, CA, USA: Acta Press, 2007, 6 p.

A method to produce patterned, controlled size triangulation of Boundary Representations is presented. Although the produced patterned triangulations are not immediately suited for fast visualization, they were used in Fixed Grid Finite Element Analysis, and do provide a control on the aspect ratio or shape factor of the triangles produced. The method presented first calculates a triangulation in the parameter space of the faces in which the B-Rep is partitioned and then maps it to 3D space. Special emphasis is set in ensuring that the triangulations of neighboring faces meet in a seamless manner, therefore ensuring that a borderless C² 2-manifold would have as triangulation a C° borderless 2- manifold. The method works properly under the conditions (i) the parametric form of the face is a 1-1 function, (ii) the parametric pre-image of a parametric face is a connected region, and (iii) the user-requested sampling frequency ( samples per length unit ) is higher than twice the spatial frequency of the features in the B-Rep ( thus respecting the Nyquist principle ). As the conditions (i) and (ii) are possible under face reparameterization or sub-division and the condition (iii) is the minimum that a triangulation should comply with, the method is deemed as generally applicable.

Brazilian Computer Society (SBC): 9th Symposium on Virtual and Augmented Reality. Proceedings 2007, pp. 324-326

Mobile augmented reality applications are in need of tracking systems which can be wearable and do not cause high processing load, while still offering reasonable robustness, performance and accuracy. The motivation to develop yet another tracking algorithm is two-fold. Existing approaches use classical optimization techniques, which 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. Results show that our tracking system achieves competitive accuracy levels, while being highly stable and affordable.

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

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.

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

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.

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

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.

Die vorliegende Bachelorarbeit befasst sich mit verschiedenen optischen Kalibrierverfahren für Infrarotkameras. Solche Kameras werden häufig für optische, markerbasierte Trackingsysteme verwendet - vor allen Dingen für AR/VR Anwendungen - um die 3D Position von Benutzern oder Interaktionsgeräten zu ermitteln. Je besser die verwendeten Infrarotkameras kalibriert werden können, desto besser sind die Ergebnisse der Positionsbestimmung. Da aktuelle Systeme sehr teuer sind und nur von grossen Firmen beispielsweise der Automobilindustrie eingsetzt werden, wurden im Rahmen eines Industrieprojektes am Fraunhofer-IGD sogenannte "Low Cost" Infrarotkameras gebaut, um zusammen mit geeigneter stereo-tracking Software eine günstigere Alternative zu schaffen bei angemessener Genauigkeit. Für eine Kamerakalibrierung müssen die intrinsischen Parameter der Kamera ermittelt werden. Zu diesen Parametern gehören die Brennweite f, der Mittelpunkt (Cx,Cy) der optischen Achse, welcher zugleich auch Mittelpunkt der radialen (k1, k2) und tangentialen (p1, p2) Linsenverzerrung ist, der Parameter , gibt die Schiefe der CCD-Bildachsen an und der Skalierungsfaktor sx. Geprüft wurde, welcher Algorithmus reproduzierbare und plausible intrinsische Parameter liefert. Dazu wurden die Methoden nach Roger Tsai und nach Zhengyou Zhang implementiert und erstmalig miteinander verglichen. Die zur Kalibrierung benötigten Bilder, bzw. Punkte wurden mit einer Holzvorrichtung und an einer Drehbank aufgenommen. Sie drehten und neigten das zuvor erstellte Schachbrettmuster in vorher definierte Richtungen. Bei der Auswertung der so aufgenommenen Bilder stellte sich heraus, dass beide Algorithmen bessere Ergebnisse liefern, wenn das Kalibrierungsmuster um 75°bis 45°geneigt ist. Dazu wurde ein Verfahren entwickelt, das die Neigung ermittelt und die für die Kalibrierung ungeeigneten Bilder herausfiltert. Durch Messungen wurde herausgefunden, dass die nichtkoplanare Methode nach Tsai das Bild mit einer Abweichung von 0.07350 px besser entzerrte, als die koplanare Version mit 0.22475 px und die Methode nach Zhang mit 0.15800 px. Die wahre effektive Fokuslänge konnte nicht ermittelt werden, da sie nicht der Brennweite des Optikherstellers entspricht. Die kleinste Standardabweichung der Fokuslänge konnte durch den nicht koplanaren Algorithmus nach Tsai kalibriert werden. Da diese Kalibrierungsmethode zu aufwendig ist und die koplanare Version zu instabile Werte lieferte, wurde zu Gunsten der Zhang Methode entschieden.

Ottjes, Jaap (Ed.) et al.: Industrial Simulation Conference 2007. Proceedings : ISC 2007. Ostend: EUROSIS-ETI, 2007, pp. 324-330

This work presents a versatile real-time simulator for training workers in the operation of construction machinery. With the aim of reducing the accident rate in the construction sector, a realistic AR scene improves the user experience. Our work addresses two stages of the training process. First, the instructor designs the working environment and the exercises with a specifically developed Scene Editor tool. Then, these exercises are run by the simulator. The simulation setup consists of a real cabin placed on a motion platform in order to provide a realistic interaction with the system and a stereoscopic augmented reality system for visualization. Visualization has been implemented as a chroma-key-based mixed reality system. This paper describes the development of the Visualization subsystem of this simulator.

HCI International 2007. Proceedings and Posters [DVD-ROM] : With 8 further Associated Conferences. Berlin, Heidelberg, New York: Springer, 2007. (Lecture Notes in Computer Science (LNCS)), LNCS 4566, pp. 290-299

We present the work on a simulator of construction machinery developed to train workers in their safe use. The simulation setup consists of a real versatile cabin placed on a motion platform in order to provide a realistic interaction with the system and a stereoscopic augmented reality system for visualization. We present some insights into the mixed reality setup we used for complex construction machines and discuss the interaction and usability problems that have arisen during its development and testing. Visualization has been implemented as a chroma-key-based mixed reality system, which combines the 3D virtual environment, the real cabin interior, and some superimposed messages to the user. As a result of our experience, we describe the main problems encountered from a usability and ergonomics point of view.

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

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.

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

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.

Technische Universität Dresden. Institut für Fördertechnik, Baumaschinen und Logistik: Baumaschinentechnik 2006 : Ideen, Konzepte, Lösungen. (Schriftenreihe der Forschungsvereinigung Bau- und Baustoffmaschinen 34), pp. 167-181

This paper deals with the approaches used for the development of the real-time dynamic models and a mixed reality setup for simulating four different types of construction machinery in the framework of the European Collective Research project "VAR-TRAINER". The project objective is to create an affordable training platform for construction operators focusing on aspects of safety at work and based on the use of real-time simulators.

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

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.

Fischer, Xavier (Ed.) et al.: Research in Interactive Design. Volume 2. Proceedings : Proceedings of the Virtual Concept 2006. Paris, Berlin, Heidelberg: Springer, 2006, 10 p.

The application of computer graphics and communication technology in the product development process leads to virtual engineering that, besides excellence in engineering, 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 simulation, to maintenance), providing examples for virtual engineering tools and focusing on the importance of real-time systems.

Fischer, Xavier (Ed.) et al.: Research in Interactive Design. Volume 2. Proceedings : Proceedings of the Virtual Concept 2006. Paris, Berlin, Heidelberg: Springer, 2006, 3 p.

Real-time scientific simulations usually require high performance platforms to deal with the massive numerical calculations. The enhancement of these simulations in personal consumer applications, made the chip industry to develop low-cost powerful specific hardware. Graphics (GPU) and physics (PPU) hardware and the multitask evolution of CPUs are the main elements that provide the real-time on that kind of applications. Consequently, engineering based applications can also take advantages of these processors to perform their simulations on PCs instead of PC clusters or supercomputers. This work presents an introduction of a PhD research that emphasize on these new hardware features and how they can work together in favor of achieving the real-time simulation and visualization for engineering based applications. These applications can successfully be benefited from the general purpose using graphics hardware, from the new CPUs streaming architecture, from the new physics hardware, and mainly from load-balancing of instructions among these hardware.

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

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.

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

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.

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

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.

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

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.

Society of CAD/CAM Engineers (SCCE): Proceedings of the SCCE CAD/CAM Conference : Book of Abstracts & Proceedings CD-ROM. Pyungchang, Korea, 2006, pp. 20-25

AICI is VR/AR Library Toolkit for applications running in immersive environments. It provides basic functions to handle all kind of VR/AR relevant input, output devices, multimodal interfaces, 3D user interface, operation handling and multi-threading. The goal of AICI is to let the developer concentrate on their application and let AICI handle the difficulties of VR. AICI focus on keeping flexibility and an architectural integration of all technologies specially required for the evaluation application in the industrial product development process. Here the architecture of AICI and its user interaction concept is presented.

Machinery specific simulators are designed for realistic and immersive "look and feel" of environments and behaviors of the real artifacts they resemble. But often only the "feel" component of such simulators is credible due to a lack of a realistic rendering. Current simulators use the graphic cards fixed function pipeline, and do not use the second processor unit, the Graphics Processing Unit (GPU) they have access to. Most of their high quality rendering is done by applying texture mapping techniques. In this work it is shown how to improve the rendering of specific materials and environments applying the new OpenGL shading language (GLSL) defined in the OpenGL 2.0 standard. Special attention is given to the rendering of weather conditions and soil as they contribute most to the environment perception in a construction machinery simulator, which will be the test environment of the developments shown in this work. The presented approach is implemented as part of the framework VAR-Trainer [VT05], which is an European funded Research and Development project whose main objective is the development of an advanced simulator platform for heavy construction machinery. VAR-Trainer uses the open source scene graph and renderer library OpenSG [Ope05c] that is based on OpenGL. Two methods for rendering a scene are implemented in this work: shader-based and texture mapping techniques. Using the two methods the assumption that a higher level of realism is gained using shaders is evaluated and a perception and importance metric is developed. The result for a construction site scenario is that soil and atmospheric effects are the most relevant visual effects to be included , followed by rain and clouds rendering, whereas the rendering of a realistic sky could be neglected, if, for instance, general performance criteria have to be considered.

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

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.

This project aims at developing a novel feature movement mechanism for Finite Element Analysis (FEA) meshes through a haptic pen (Phantom stylus) within a Virtual Reality (VR)-based environment. The tools developed in this project allow for making real-time feature movements and gesture-based manipulations on surface and volume meshes which lead to "what-if-analysis" on the fly. Focus of the work is the real-time operation in highly resources and computing intensive envision meshes. The approach here presented might enable the project to head towards conceptual simulations within the engineering domain (targeting at linear static analysis). Methodologies are presented for interactive mesh modifications within linear static problems based on tetrahedral meshes, 'on-the-fly' feature movements (such as through holes), the adaptation of the surrounding volume mesh, fast and adaptive mesh refinement techniques, quality measures to ensure the consistency and quality of the newly, 'on-the-fly' generated elements and the necessary topological operations for unstructured triangular tetrahedral mesh. Because of the interactive environment, all operations have to comply with the real-time constrain and have to be evaluated for local simplicial elements. In order to reduce the analysis and computation overhead, a new idea was introduced for local evaluations based on an integrated submodeling procedure. From global to local and coarse to fine, here additional constrains like influence and consistency on/with the overall model have to be considered. The approach take essential boundary conditions into account which constrain the isolated part of the submodel and which are derived from the global solution. Within the engineering environments, the explicit and implicit methodologies from global to locally detailed analysis (from coarse to refined results) allows the approach to head for fast preliminary design evaluations. The project has relevance for the computer graphics field because it will offer human interaction with feedbacks for real-time applications, supporting industrial applications. In the same way, the industrial companies (like aircraft and automobile manufacturers) could take benefit of the results, since it supports engineers with tools for conceptual simulations and shortening analysis cycles, reducing cost and time to market.

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).

The Bachelor thesis realized a consistency mechanism in the domain of Virtual Styling. It is able to check the feasibility of free-form creation and deformation operations considering the conformance of newly introduced continuity constraints to existing ones, and propagates deformations through the constraint graph by applying necessary surface modifications such that the continuity constraints at the transition between adjacent free-form surfaces are satisfied, leading the system into a consistent state. Some measures have been adopted to ensure a performing consistency mechanism and constraint satisfaction suitable for virtual conceptual design. One is to explore the representation of the constraint satisfaction problem in an extended constraint hyper graph. Together with the rules defined for the consistent growth and modification of the free-form model, the approach allows for an efficient consistency verification and propagation of changes throughout the constraint graph. The consistency mechanism could further be optimized by exploring the geometric properties of adjacent NURBS surfaces with continuous transition, where the affected area of shape deformations is limited to the 2-neighbourhood of a modified shape node in the constraint graph, reducing the constraint satisfaction problem to a well defined sub-graph of a given constraint graph.

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

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.

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

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.

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

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.

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.

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.

Ziel des Projektes war die Umsetzung von Kooperationsmöglichkeiten der Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. und brasilianischen Forschungseinrichtungen zur Stärkung der regional tätigen Industrie. Das Projekt wurde im Rahmen des Deutsch-Brasilianischen Abkommens über die Zusammenarbeit in Wissenschaftlicher Forschung und Technologischer Entwicklung durchgeführt. Von der deutschen Seite wurde das Projekt von der Fraunhofer-Gesellschaft (FhG), vertreten durch die Fraunhofer-Institute IPA und IGD, durchgeführt. Von der brasilianischen Seite wurde das Projekt von der Regierung des Bundesstaates Rio Grande do Sul und von der Bundesregierung sowie von einem Zusammenschluss mit den regionalen angeschlossenen Unternehmen und nahe stehenden Organisationen wie SENAI-RS, FIERGS, SEBRAE/RS und AHK unterstützt. Das Ergebnis ist die Implementierung eines "Kompetenzzentrums für angewandte Forschung und Entwicklung (CETA)", in Anlehnung an das "Fraunhofer-Modell", dessen Grundfinanzierung durch SENAI-RS gesichert ist. Von CETA koordiniert wurden zahlreiche deutsch-brasilianische F&E-Projekte in den Bereichen Produkt- und Prozessoptimierung und Informations- und Kommunikationstechnologie akquiriert. Alleine im Berichtszeitraum sind sieben F&E-Projekte abgeschlossen worden. Elf weitere befanden sich am Ende des Berichtszeitraumes noch in Bearbeitung. Beauftragt von brasilianischen Unternehmen wurden einige dieser Projekte durch brasilianische Fördermittel co-finanziert. Die meisten Projekte wurden von einen Konsortium aus brasilianischen F&E-Einrichtungen und Fraunhofer-Instituten unter der Koordination von CETA bearbeitet. Deutsche Universitäten konnten ebenfalls involviert werden. Die Netzwerkbildung zwischen CETA und Fraunhofer konnte auf verschiedenen Ebenen nachhaltig aufgebaut werden. Einerseits sind dies die persönlichen Kontakte zwischen CETA- und Fraunhofer-Mitarbeitern, die durch den Austausch von Wissenschaftlern und in durchgeführten F&E-Projekten entstanden sind. Andererseits wird durch Rahmenabkommen zwischen der Fraunhofer-Gesellschaft mit SENAI-RS und mit FINEP (brasilianischer Projektträger) das entstandene deutsch-brasilianischen Netzwerk für angewandte Forschung auch Institutionell unterstützt, was die Basis für eine zukünftige Ausweitung des CETA-Modells auf weitere brasilianische Bundesstaaten bildet.

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

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.

Das Modelliersystem SmartSketches ist darauf ausgelegt, eine virtuelle Umgebung für das Styling und die frühe Konzeptentwicklung von Freiformgeometrien anzubieten. Dazu adressiert es auch die Kontrolle stetiger Flächenübergänge, wozu geometrische und parametrische Stetigkeitszwangsbedingungen (Continuity Constraints) auf adjazente Freiformflächen in NURBS-Darstellung angewendet werden können. Die Diplomarbeit ist in zwei aufeinander aufbauenden Teilaufgaben gegliedert gewesen. Zunächst wurde eine effiziente Datenstruktur zum Erfassen und Verwalten eines Constraint-Graphen für Continuity-Constraints zwischen adjazenten Freiformflächen (Shapes) entwickelt. Anschließend wurden Strategien entwickelt, um Constraint Satisfaction Problems (CSP) für Freiformstetigkeitsprobleme zu beschreiben. Dabei wurden sieben zu berücksichtigende Fälle identifiziert. Hauptstrategie der Erstellung eines CSP ist die Gruppierung adjazenter Shapes, welche mit dem gleichen Typ von Continuity-Constraint in Beziehung gesetzt sind, innerhalb eines Parts. Die Gründe hierfür sind, dass SmartSketches einerseits eine leistungsfähige Implementierung zur stetigen Deformation einer Menge benachbarter NURBS-Flächen entsprechend einem vorgegebenen Stetigkeitszustandes zur Verfügung stellt. Andererseits entspricht es einer Fertigungssicht auf ein Modell, dass Flächen eines Bauteils eine konsistente interrne Stetigkeit, abhängig vom Typ des Fertigungsverfahrens i.d.R. C1 oder C2, aufweisen. Gegründet auf dieser Annahme unterscheiden die sieben Fälle zwischen den Situationen in denen Shapes zu einem Part vereinigt werden, in denen Shape-Beziehungen interne Part-Relationen definieren, und dem Fall unrealisierbarer Stetigkeitsanforderungen, die im Konflikt mit vorher definierten Continuity-Constraint stehen.

Im Rahmen dieser Master Thesis wurde der Prototyp eines Annotationstools entwickelt, der die Annotation verschiedener Dokumentenformate erlaubt. Zum gegenwärtigen Zeitpunkt wird von diesem Prototyp die Annotation dreier verschiedener Dokumentenformate unterstützt. Diese Dokumententypen sind: MS Word-Dokumente, MS PowerPoint-Präsentationen und MS Outlook E-Mail- Dokumente. Um eine Annotation dieser Dokumentenformate zu ermöglichen, wurden die jeweiligen Applikationen durch COM-AddIns gezielt um die Annotationsfunktionalität erweitert. Durch dieses AddIn-Konzept wird es dem Benutzer ermöglicht, die gleichen Tools, die er zur Erstellung oder Betrachtung von Dokumenten verwendet werden, ebenfalls zur Annotation dieser Dokumente zu verwenden. So wird dem Benutzer eine transparente Benutzerschnittstelle zur Verfügung gestellt, die es ihm erlaubt, Dokumente gezielt um semantische Beschreibungen zu erweitern. Auf diese Weise wird der Benutzer vom Zwang befreit, sich an eine neue Programm-Umgebung zu gewöhnen. Die Integration der Handschrifterkennungstechnologien erlaubt eine einfache und intuitive Annotation von Dokumenten. Durch die Integration dieser Technologie wird es dem Nutzer ermöglicht, direkt auf dem geöffneten Dokument handschriftlich zu annotieren. Auf diese Weise ist es möglich, das "natürliche" Annotationsverfahren, wie es seit langem für gedruckte Dokumente üblich ist, für die Verwendung auf dem Personal Computer zu adaptieren.

Das Ziel meiner Arbeit war die Entwicklung von Werkzeugen zur interaktiven Visualisierung von Simulationsergebnissen in Virtual- und Augmented-Reality Umgebungen. Dabei sollten unterschiedliche Interaktions- und Visualisierungsmethoden bereitgestellt werden, welche dem Anwender eine möglichst effiziente und intuitive Interpretation der Daten erlauben. Im Vordergrund standen daher fortgeschrittene Verfahren wie die direkte Volumenvisualisierung, die Erzeugung und Animation von Strömungstexturen, sowie die interaktive Berechnung und Darstellung von Partikelbahnen. Diese Verfahren wurden für die interaktive Visualisierung nicht-regulärer Gitterstrukturen so erweitert, das sie die Echtzeitanforderungen von VR- und AR-Umgebungen erfüllen. Um einen möglichst optimalen Nutzen der verfügbaren Hardwareressourcen zu gewährleisten, wurden die Möglichkeiten programmierbarer Graphikkarten handelsüblicher PC-Systeme untersucht. Durch den gezielten und kombinierte Einsatz von hardwarenahen Methoden und optimierten Softwareverfahren konnte die für VR- und AR-Anwendungen erforderliche Darstellungsgeschwindigkeit erzielt werden. Dabei ist die erreichte Bildqualität mit den Ergebnissen nicht-interaktiver Methoden vergleichbar. Verfahren zur Geometriekompression ermöglichen es zudem auch größere Datensätze mit hinreichenden Bildwiederholraten darzustellen. Die realisierten Methoden wurden in ein neu entwickeltes Softwaresystem integriert, welches dem Benutzer die erforderlichen Interaktionsmöglichkeiten zur Navigation sowie zur Kontrolle der Darstellungen in virtuellen und erweiterten Realitätsumgebungen bereitstellt. Mit Hilfe neuer Interaktionskomponenten kann der Anwender die zur Volumenvisualisierung erforderliche Klassifikation in interaktiver Weise vornehmen und profitiert dabei von der 3D-Darstellung der jeweiligen Transferfunktion. Weitere 3D Bedienelemente dienen zur interaktiven Manipulation und Animation von Strömungstexturen, der Positionierung von Startpunkten, sowie der anschließenden schnellen Berechnung und Darstellung von Strömungsproben. Die entwickelten Methoden bieten dem Anwender vielfältige Möglichkeiten zur interaktiven Visualisierung von Simulationsergebnissen in virtuellen und erweiterten Realitätsumgebungen. Darüber hinaus lassen sich die präsentierten Lösungen auch für weitere Anwendungsbereiche einsetzen. So eröffnet der Einsatz von Augmented Reality Techniken neue und effiziente Möglichkeiten zum unmittelbaren Abgleich von physikalischen Experimenten und numerischen Simulationen. Die im Rahmen dieser Arbeit realisierten Methoden bieten zudem verschiedene Möglichkeiten für weitere Entwicklungen, wie z.B. den Einsatz von PC-Cluster Systemen zur zusätzlichen Steigerung der Darstellungsleistung, oder die Einbeziehung weiterer Interaktionsformen.

Skala, Vaclav (Ed.): Journal of WSCG Volume 13 No. 1-3, 2005. Proceedings. Plzen: University of West Bohemia, 2005, pp. 25-32

In this paper we present our solution for fast, direct volume rendering of unstructured grids on standard PC workstations. We describe our modification of the incremental slicing approach for achieving high performance as well as our implementation of geometry-compression methods for minimizing the memory requirements. Furthermore, we show our implementation for the interactive modification of transfer functions (classification) in a virtual reality environment by using 3D interaction widgets.

International Journal of Computer Applications in Technology, Vol.23 (2005), 2/3/4, pp. 192-202

CAx systems typically encode the semantics of shapes as so-called parametric features on different levels of abstraction. Here we discuss an approach that combines feature-based parametric modelling with techniques from the field of knowledge representation and ontological reasoning. Parametric models refer to feature ontologies that model feature semantics on several levels of granularity. On higher levels, the interrelation between features and feature interoperability is captured whereas on lower levels a feature is described in terms of geometric, topological and parametric entities. Different engineering tasks can utilise feature ontologies as a basis for application-specific shape reasoning across several modelling layers.

ProSTEP iViP Association: ProSTEP iVip Science Days 2005 : Cross-Domain Engineering. Bobingen: Kessler Verlagsdruckerei, 2005, pp. 256-257

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

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.

Workshop towards Semantic Virtual Environments, pp. 17-26

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

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.

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

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.

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

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.

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

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.

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

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.

Computational simulation is widely used in the industry for the optimisation of production processes. The computational simulation of the production of spunbond nonwoven fabrics is a new and emerging field of research. This thesis covers the development of analysis techniques for several aspects of simulated nonwoven fabrics, i.e. fabrics that are made of randomly oriented fibres. We propose a set of visualisation techniques including colour coding, parallel coordinates, tangent colour mapping, and surface reconstruction for the analysis of the simulation data. Furthermore, we propose a model for realistic rendering of nonwoven fabrics in order to create a virtual preview of the simulated nonwoven fabric. This is a topic that has not been addressed before. The rendering model is based based solely on the output of the simulation and relies on existing techniques for realistic rendering of fibrous materials - covering shading, self-shadowing, depth-sorting, and antialiasing. Both aspects, information visualisation and realistic rendering, are required to run at interactive framerates, thus they are accelerated by exploiting modern programmable graphics hardware. As a result, we have achieved major improvements over the previously used visualisation approaches, offering a unified solution for the interactive visualisation and exploration of simulated nonwoven fabrics. We had to apply our model for realistic rendering of nonwoven fabrics to artificial datasets due to restrictions of existing datasets. The results are promising, although our model for realistic rendering of nonwovens still has to prove itself on future simulation results.

Virtuelle Crashsimulationen lösen reale Crashtests im Fahrzeugbau mehr und mehr ab, da sie den Entwicklungsprozess verkürzen und so die Entwicklungskosten senken. Im Gegensatz zur ständigen Weiterentwicklung der Crashsimulationsverfahren in den letzten Jahren, wurde im Bereich der Visualisierung von Simulationsergebnissen nur wenig geforscht. Die Folge sind komplexe Ergebnisdatensätze, die durch herkömmliche Visualisierungsverfahren nicht mit akzeptablen Bildwiederholraten darzustellen sind. In der vorliegenden Arbeit wird ein Verfahren vorgestellt, mit dem die Komplexität der Ergebnisdaten von Crashsimulationen gezielt verringert werden kann um so eine interaktive Visualisierung zu ermöglichen. Dazu wurden Verfahren zur Simplifizierung und progressiven Kodierung polygonaler Netze, welche aus der Computergrafik bekannt sind, an die Anforderungen von Crashsimulationsergebnissen angepasst. Die Verfahren wurden zur Verarbeitung zeitabhängiger Polygonnetze mittels Multiquadriken erweitert und auf die Simplifizierung gemischter Drei- und Vierecksnetze auf Basis des Kantenkollabierens verallgemeinert. Auf diese Weise ist die Erzeugung einer Multiskalendarstellung von Simulationsergebnissen möglich, welche eine progressive Übertragung und ein adaptives Level-of-Detail bereitstellt. Der im Rahmen der Arbeit entwickelte Dezimierer erlaubt die Vereinfachung von Crashsimulationsergebnissen mit 1 Million Knoten und 25 Zeitschritten in drei Minuten. Bei 10% der Knoten konnte ein Approximationsfehler von unter 1% gemessen werden.

Das Projekt WIDE beschäftigt sich mit der Problematik, das Wissen eines Unternehmens in einer Form abzuspeichern, in der alle Nutzer ohne größere Probleme alle relevanten Informationen zu jeder Zeit auffinden können. Innerhalb des Projekts erfolgt die Suche nach Dokumenten auf Metadatenebene. Die Metadaten werden hierzu mit RDF beschrieben. Um diese RDF-Beschreibungen automatisch zu erstellen, soll im Rahmen der Diplomarbeit eine Softwarekomponente erstellt werden, die die relevanten Metadaten aus vorgegebenen Dokumenten liest und in eine RDF-Datei schreibt. Die Metadaten erhält die Softwarekomponente von einer Ontologie, die ebenfalls im Rahmen der Diplomarbeit erstellt wird. Die Extraktion der Metadaten soll für zwei Dokumenttypen möglich sein. Die Dokumente liegen in einem Microsoft Word-Format vor. Die Dokumenttypen und die dazugehörenden Metadaten wurden in einer Ontologie modelliert. Hierzu wurde der Ontologieeditor Protégé verwendet. Die Softwarekomponente beinhaltet zwei Algorithmen. Der eine dient dem Auffinden der Metadaten innerhalb der Dokumente, die in eine RDF-Datei geschrieben werden sollen. Er berücksichtigt die unterschiedliche Anordnung der Metadaten innerhalb der Patente und Protokolle. Der zweite Algorithmus kommt zum Einsatz, wenn ein Tabellenknoten gefunden wurde. Er extrahiert diejenigen Metadaten aus der Tabelle, die per E-Mail versendet werden sollen.

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.

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.

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

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).

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

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).

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

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.

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.

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

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.

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

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.

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

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.

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

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.

Workshop towards Semantic Virtual Environments, pp. 127-137

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.

Um Freiformflächen in virtuellen Umgebungen wie SmartSketches zu erstellen, gibt es im wesentlichen zwei verschiedene Grundprinzipien: zum Einen wird eine Fläche zwischen zwei Kurven interpoliert (Skinning) und zum Anderen wird, ausgehend von einer existierenden Kurve, eine Fläche extrudiert. Bislang mussten jedoch immer zuerst eine oder mehrere Kurven modelliert werden, um daraus anschließend Freiformflächen erzeugen zu können. Dadurch wurden die erzeugten Freiformflächen an den Verbindungskanten immer unstetig, da der Übergang zwischen den Flächen nicht definiert war. Die Erzeugung adjazenter Flächen war in expliziter Form nicht möglich. Um diese Einschränkungen aufzuheben, wurden in dieser Arbeit Methoden entwickelt, die es erlauben, die Stetigkeiten an beliebigen Übergängen zwischen adjazenten Flächen zu kontrollieren und die Möglichkeit bieten, stetig adjazente Freiformflächen an beliebige Randkurven existierender Flächen anzumodellieren. Dadurch wird es ebenfalls möglich, ausgehend von mehreren Freiformflächen, Flächenverbände zu erstellen, die als ein Körper angesehen und zum Beispiel deformiert werden können. Durch die Skin- und die Extrude- Funktion, die automatisch stetige Übergänge zu benachbarten Flächen erzeugen, können so einfach und schnell Flächenverbände erzeugt werden, die ein vom Benutzer kontrolliertes Verhalten an ihren Übergängen haben, womit die Mächtigkeit des Werkzeug SmartSketches zum Virtuellen Styling deutlich verbessert wurde.

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

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.

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

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.

Information Society Technologies (IST): Proceedings of the First European Workshop on Model Driven Architecture with Emphasis on Industrial Application : Participant's Edition. Enschede: University of Twente, 2004, pp. 97-104

This paper discusses the results and experiences gained from the project Model Driven Development of Telecommunication Systems (MDTS) which is a joint project of three institutes of the Fraunhofer Society. The main goal of the project was to define a model driven software construction process, which enables the integration of system development and system test. It included the provision of a set of supporting tools to increase the level of automation in this process. The developed concepts have been applied in the telecommunication domain using an example application. This application supports mobile workers in critical industrial domains like aircraft maintenance or chemical production.

Die vorliegende Diplomarbeit beschäftigt sich mit dem Entwurf eines Kriterienkatalogs zur Evaluierung von Ontologie-Editoren (OE) und der Durchführung dieser Evaluation an einer Gruppe von OE. Es werden zunächst der Bezug zu dem Umfeld der Diplomarbeit hergestellt und einige theoretische Grundlagen erläutert, die zum Verständnis der weiteren Ausführungen hilfreich sind. Dazu zählen allgemeine Beschreibungen von Ontologiebeschreibungssprachen wie z.B. des Resource Description Frameworks" (RDF) oder auch von RDF Abfragesprachen wie z.B. RDF Query Language" (RQL). Des weiteren wird ein ontologiebasiertes Information Retrieval System vorgestellt, das als Gesamtsystem den Themenbereich dieser Diplomarbeit beinhaltet. Nach den theoretischen Ausführungen widmet sich diese Arbeit dann dem detaillierten Entwurf des Kriterienkatalogs, der eigentlichen Evaluation der Editoren, der Ergebniserläuterung und der daraus resultierenden Empfehlung an das Fraunhofer Institut für Graphische Datenverarbeitung und deren Abteilung A2.

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

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.

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

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.

Die vorliegende Arbeit befasst sich mit der Beschleunigung globaler Beleuchtungsalgorithmen durch die GPU. Insbesondere wird evaluiert, inwieweit die GPU dazu geeignet ist, globale Beleuchtung für VR Umgebungen nutzbar zu machen. Zu diesem Zweck ist ein vollständig auf der GPU laufender Ray Tracer implementiert worden. Dieser wurde dann um Photon Mapping erweitert. Da die GPU jedoch durch das Ray Tracing bereits stark beansprucht war, wurde das Photon Mapping nicht auf der GPU implementiert, sondern in einen auf der CPU laufenden Preprozess ausgelagert. Dazu wurde jedes Objekt der Szene mit einer Textur (der Light Map) versehen. Für jedes Texel dieser Light Map wurde die diffuse indirekte Beleuchtung durch klassisches Photon Mapping berechnet und in diesem Texel gespeichert. Die im Preprozess erstellten Light Maps wurden danach beim Rendering zu den durch Ray Tracing ermittelten Beleuchtungswerten addiert. Auf diese Weise lassen sich Effekte wie Caustics und Color Bleeding erfassen. Ferner wird der Einfluss von BRDFs auf die Geschwindigkeit des Ray Tracers untersucht und ein kurzer Ausblick darauf gegeben, wie Multi-Threading benutzt werden kann, um Arbeit zwischen GPU und CPU zu verteilen.

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

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.

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

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.

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

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.

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

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.

Swiss Federal Institute of Technology (EPFL), Virtual Reality Lab (VRlab): Third International Workshop on Virtual Rehabilitation 2004. Proceedings : IWVR 2004. Lausanne, 2004, pp. 63-68

The initative INToIND "Innovative Technologies for Inclusion Disabilities" connects several key issues to develop and demonstrate the use of cost-effecitve interactive Virtual Worlds, to help integrate young disabled subjects in work. INToIND is meant to prrove the technical and clinical viability of advanced synthetic environments as Virtual Reality (VR) in clinical and cognitve psychology. A key goal of the initiative is to explore the medium/long term impact of Virtual Reality in Cognitive Disability. INToIND intends to improve on prior research conducted in Europe and the US that demonstrated the use of Virtual Worlds, similar to those popular in entertainment, education and military training, to enhance the clinical treatment of phobias and panic attac of cognitive disabled persons. Unlike real life treatment, controlled exposure to anxiety provoking situatioins excludes overwhelming stress and security risks; it thus changes the patient's attitude towards certain situations ans opens the way for self-driven rehabilitation.

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.

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.

Die virtuelle konzeptionelle Modellierungsumgebung SmartSketches wird zurzeit um einen Feature-basierten parametrischen Ansatz zur Baugruppen und Bauteile Modellierung erweitert. Ziel dieser Erweiterung ist die Realisierung einer intuitiven Schnittstelle für die Konzeption und Verkörperung (Verwirklichung) von Mechanismen in virtuellen Umgebungen, die die kritischen Schnittstellen zwischen involvierten Bauteilen, Verbindungen und Kinematischen Beziehungen in Betracht zieht. Mit dem Feature-basierten Ansatz werden Benutzer bei der Definition der parametrischen Wechselwirkungen zwischen den Bauteilen einer Baugruppe sowie der inaktiven Simulation und Validierung der Mechanismen zu jeder Zeit der Modellierungssitzung unterstützt. Dafür werden Features und Parametrische Daten in ein Netz von geometrischen Constraints gestellt, die berechnet werden wann immer der Benutzer mit dem Modell interagiert, wie durch einfügen oder modifizieren von Bauteilen oder Constraints. Das Problem bei diesem Ansatz ist die computertechnisch gesehen teure Berechnung der Constraints, insbesondere bei der kinematischen Simulation, in welcher zur Zeit nur einfache Mechanismen mit ungefähr 4 Bauteilen was ungefähr 30-40 Constraints entspricht in Echtzeit berechnet werden können. Das Ziel dieser Diplomarbeit ist es daher die Performanz des Systems zu erhöhen, indem man sich den Vorteil zu nutze macht der sich aus der Beobachtung ergibt, das es vom momentanen System Modus sowie dem Typus der Arbeit abhängt, ob ein kleines Subset von Constraints die notwendig sind auch ausreichend sind um zu garantieren das sich der virtuelle Mechanismus korrekt verhält. Zum Beispiel müssen bei der Positionierung von Bauteilen in einer Baugruppenmodellierung oder dem Hinzufügen von Verbindungen zwischen Bauteilen, nur die Constraints in Betracht gezogen werden welche die relative Position und den Grad der Freiheit zwischen den einzelnen Bauteilen bestimmen. Ähnlich verhält es sich bei der Modifikation oder dem Hinzufügen von Eigenschaften eines Bauteils. Hier sind nur die Constraints die das Bauteil definieren von Bedeutung, alle anderen Bauteile sowie die Beziehungen zwischen den Bauteilen sind außerhalb des zu beachtenden Bereichs. Das Resultat dieser Diplomaufgabenstellung ist die Realisierung einer Funktionalität in SmartSketches, die es mittels eines semantischen Filters, erlaubt die Sicht auf die Produktinformation die abhängig vom aktuellen Modellierungskontext ist, der wiederum von der aktuellen User Operation definiert wird, zu beschränken. Die realisierten Modellierungskontexte sind eine Bauteilesicht, während der Modellierung von Bauteilen und eine Baugruppensicht für die Baugruppenmodellierung und das kinematische validieren der vorhandenen Mechanismen. Damit ist es nun Möglich die Anzahl der aktiven Constraints für die kinematische Simulation zu einer durchschnittlichen Anzahl von zwei Constraints pro Verbindung zu reduzieren und somit den Zusammenbau und die Echtzeit Simulation eines Mechanismus mit bis zu 20-30 involvierten Bauteilen zu ermöglichen.

Aufgabenstellung der Diplomarbeit ist die Realisierung eines Virtual Conceptual Design (VCD) Systems, das die erarbeiteten essentiellen Anforderungen an ein benutzerfreundliches und in der Praxis einsetzbares CACD-System (Computer Aided Concpetual Design) prototypisch umsetzt. Die wesentliche Funktionalität des realisierten VCD-Systems beinhaltet die Einbindung semantischer Modellier- und Analyseoperationen, die ein kreatives und intuitives Modellieren von funktionalen Konzepten unterstützen und es dem Anwender erlauben, jederzeit einen sukzessiv entstehenden Mechanismus durch kinematische Simulation zu validieren und zu verifizieren. Zur Modellierung von Bauteilen stehen dem Anwender für das Conceptual Design adaptierte Feature-basierte und parametrische Methoden zur Verfügung. Darauf aufbauend realisiert die Arbeit auch einen Bauteilekatalog, dessen Struktur für einen einfachen, zusammenbauorientierten Mensch-Maschine-Dialog auf einer Taxonomie basiert, die die Bauteile entsprechend ihren Konnektoren, d.h. den Verbindungselementen zur Realisierung von Gelenken, gliedert. Kern des realisierten VCD-Systems ist ein Schichtenmodell zur Abbildung von Produktsemantik. Die Schichten dieses Modells sind eine parametrische Schicht, die es erlaubt, geometrische Zwangsbedingungen (Constraints) zwischen topologischen Elementen zu definieren. Die darauf aufbauende Shape-Schicht erlaubt dann die Modellierung von abstrakten Formelementen (Features) und deren durch Constraints definierten Wechselwirkungen. Diese Formelemente dienen dazu, den Aufbau eines Bauteils geometrisch und funktional zu modellieren. Eine letzte Schicht realisiert schließlich ein Baugruppenmodell, in dem die Struktur von Baugruppen und Mechanismen beschrieben ist. Beziehungen zwischen Bauteilen sind hier vor allem Gelenke, die über Relationen zwischen Konnektoren in der Shape-Schicht und schließlich über Constraints zwischen Flächen und Kanten in der parametrischen Schicht modelliert sind. Schließlich wird durch Integration eines geeigneten Constraint-Solvers erreicht, dass die semantische Integrität des Produktmodells in jedem Operationsschritt hergestellt und überprüft wird. Außerdem wird damit eine kinematische Simulation von Mechanismen ermöglicht, die auf einer Echtzeitauswertung des parametrischen Modells während der interaktiven Transformation von einzelnen Bauteilen beruht.

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

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.

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.

The circumstances of a mobile computer use (i.e., application cases involving user mobility such as outdoor, on the move) require new approaches in application system development and create a high demand for specialized, task-oriented system features. Any service being offered has to be able to account for, adjust itself, and be responsive to the increasing diversity of prospective users and their unpredictable usage environments; thus, to the highly changing requirements plus platform specification and availability. The achievement of this attribute is even more challenging when the service should be a basis for a digitally mediated human-to-human communication process involving all kinds of diversity between the individual partners and technical arrangements. In this thesis work, proposals and innovative solutions to these challenges have been investigated and implemented, and are presented in this report. Some contributions of this work are: an adaptive conference system for heterogeneous computational and network environments; tools to monitor, distribute, and respond to user profiles at both the individual and collective level; adaptive, flexible individual interaction modes and media that are nevertheless consistent for a collaborative work; and a successful integrated solution -- monitoring tool plus conference system, which can be effectively integrated in a computer-supported mobile activity.

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.

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.

ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb, Vol.98 (2003), 6, pp. 310-312

Numerische Simulationen sind heute ein wichtiger Bestandteil für die aktuelle Produktentwicklung. Zur Verarbeitung, Interpretation und Kommunikation der hieraus resultierenden riesigen Datenmengen werden effiziente Analyse und Präsentationswerkzeuge benötigt. Techniken der Virtuellen Realität (VR) ermöglichen einen einfachen und intuitiven Zugang zu den Informationen. Die Kombination von virtuellen und realen Objekten und somit die Interpretation von Berechnungen in der ursprünglichen realen Umgebung werden durch Techniken der Erweiterten Realität (AR) ermöglicht. In diesem Beitrag werden Entwicklungen aus den Bereichen VR und AR vorgestellt, welche zur Zeit am Fraunhofer Institut für Graphische Datenverarbeitung durchgeführt werden. Der Beitrag bietet einen Überblick über das Visualisierungswerkzeug IDEFIx und den aktuellen Bestrebungen zur direkten Kopplung von Simulation und VR basierter Visualisierung. Des weiteren wird ein neu enwickelter Prototyp zur PC basierten Volumenvisualisierung in VR beschrieben.

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

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.

Soenen, René (Ed.) et al.: Feature Based Product Life-Cycle Modelling : Conference on Feature Modelling and Advanced Design-for-the-Life-Cycle Systems. (FEATS) 2001. Boston; Dordrecht; London: Kluwer Academic Publishers, 2003, pp. 19-39

In this paper the concept of Feature-based Virtual Engineering is presented as an approach to the integrated product development. The focus of the paper is on presenting the current state of our approach towards a feature-based parametric representation of product semantics including a concept for creating and maintaining application specific views on the product information.

ProduktDaten Journal, Vol.10 (2003), 2, pp. 48-51

The article introduces an approach towards real-time, intuitive kinematics simulation in virtual environments, which extends the current state-of-the-art in virtual assembling. The objective is to allow the validation of assemblies that include mechanisms, by experiencing the behaviour of critical transmission areas during the virtual assembly process. Kinematics properties are either extracted from CAD and converted for the virtual simulation along with the geometry or they are defined incrementally in the virtual environment building kinematic chains of parts reducing step-by-step the degrees of freedom of the assembled parts. Kinematics in the virtual environment is expressed in the form of geometric constraints, which are solved in real-time during interaction with the virtual prototypes.

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

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.

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

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.

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.

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

Verteilte Anwendungen werden heutzutage häufig über "best effort" Netzwerke betrieben. "Best effort" bedeutet, dass das Netzwerk keine Garantie über eine bestimmte Dienstgüte, auch "Quality of Service" (QoS) genannt, geben kann. Viele solche Anwendungen leiden unter den Unterschieden und teilweise starken Schwankungen in der Dienstgüte, im Besonderen der Bandbreite. Adaptive Anwendungen versuchen hier Abhilfe zu schaffen, indem sie ihr Verhalten dynamisch an die zur Verfügung stehende Netzwerkresourcen anpassen, um dem Benutzer eine akzeptable Qualität zu bieten. Dies kann z.B. durch Reduktion der Farbtiefe und Auflösung eines Videodatenstroms bei abnehmender Bandbreite erfolgen, um eine gleichmäßige Bildwiederholrate für ein flüssiges Videoerlebnis zu gewährleisten. Adaptive Anwendungen, die sich dynamisch an die gerade vorherrschende Qualität eines Übertragungsnetzwerkes anpassen, werden um so wichtiger, je mehr drahtlose Netzwerke Verbreitung finden. Drahtlose Netze unterliegen häufiger Schwankungen in der Qualität bei Datenübertragungen als rein stationäre Netzwerke. Die präsentierte Arbeit beschreibt Verfahren und Möglichkeiten zur Ermittlung von Bandbreite im mobilen Umfeld, um adaptive Anwendungen an die Netzqualität anzupassen. Dazu wurde vom Autor eine universelle Programm Bibliothek entwickelt, die speziell auf adaptive Systeme im mobilen Umfeld angepasst ist. Die erstellte Programmn Bibliothek wurde in Hinblick auf Erweiterbarkeit mit den Methoden der Softwaretechnik entwickelt und in ein adaptives Framework integriert. Die Arbeit baut auf den Erfahrungen und Erkenntnissen eines Praxissemesters bei der Fraunhofer Gesellschaft am Institut für Graphische Datenverarbeitung (IGD) in Darmstadt auf.

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

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.

Irmscher, Klaus (Ed.) et al.: Kommunikation in Verteilten Systemen (KiVS). Berlin, Offenbach: VDE-Verlag GmbH, 2003

For the development of collaborative multimedia systems two tasks need to be done often. The multimedia connection between distributed systems has to be established and the information about the currently available resources has to be gathered to adapt the application to the environment. We present solutions for these two tasks. The integration of these two solutions became part of a CORBA Component Model (CCM) based middleware and will therefore greatly reduce the development effort of such systems.

Das virtuelle Modellieren von Automobilen ist ein Gebiet der graphischen Datenverarbeitung, das in Designerkreisen zusehends an Akzeptanz gewinnt. Das Erzeugen des Packagemodells, welches von Entwicklungsingenieuren durchgeführt wird, bildet den ersten Schritt beim Design eines neuen Fahrzeugs. Die Verwendung eines parametrisierbaren Packagemodells in einer virtuellen Designumgebung macht es möglich, verschiedene Fahrzeugkonfigurationen in der virtuellen Umgebung einzusetzen und die Einhaltung ihrer Eigenschaften und Richtlinien durch eine Kollisionserkennung zu gewährleisten. Das Projekt SmartSketches ist ein System zum Modellieren von Freiformoberflächen in virtueller und erweiterter Realität. Ein Anwendungsgebiet dieses Systems ist der virtuelle Entwurf von Automobilen. Dabei gilt ein besonderes Augenmerk der Integration der einzelnen Arbeitsschritte in den frühen Phasen des Automobildesigns in einem einzelnen Softwarepaket. Ein Arbeitsschritt, der in SmartSketches integriert werden soll ist die Erzeugung eines parametrisierbaren Packagemodells. Dieser Schritt wird bislang von Entwicklungsingenieuren auf Seiten des Auftraggebers oder einer speziellen Entwicklungsabteilung des Designunternehmens durchgeführt. D.h. der Designer erhält durch das Packagemodell Richtlinien und Eigenschaften, denen das von ihm entworfene Fahrzeug genügen muss. Zur Integration dieses Arbeitsschritts in SmartSketches muss das Packagemodell in der Lage sein, viele verschiedene Fahrzeugkonfigurationen zu repräsentieren um dem Entwicklungsingenieur seinen gewohnten Freiraum bei der Entwicklung des Packages zu geben. Das Ziel dieser Arbeit ist die Entwicklung eines solchen parametrisierbaren Packagemodells für das virtuell- immersive Modellieren in SmartSketches, sowie die Realisierung einer intuitiven und übersichtlichen Benutzeroberfläche zur Steuerung des virtuellen Modells. Das Modell beinhaltet eine angemessene Zahl von Parametern, so genannten Hard- Points (Richtlinien, Ergonomische Parameter, Wünsche des Kunden, Charakteristik des Fahrzeugs, etc.), die ein zeichnerisch erstelltes Package besitzt, Diese sollen durch möglichst einfache Geometrien in der virtuellen Modellierumgebung repräsentiert werden. Die graphische Ein- und Ausgabe basiert auf Open Inventor, die Interaktionsfunktionalität wird von der VR- Bibliothek und Open Inventor- Erweiterung Studierstube zur Verfügung gestellt. Nach dem Abschluss der Packagemodellierung beginnt der Designer mit dem Entwurf des Fahrzeugs durch Erzeugen von Geometrien. Diese werden von einer Kollisionserkennung ständig auf Konformität mit den Richtlinien des Packagemodells geprüft Etwaige Verstöße gegen die Richtlinien werden dem Designer optisch mitgeteilt, um ihm eine möglichst direkte Rückmeldung zu geben.

Diese Arbeit beschreibt, welche Anforderungen an ein Whiteboard Modul, für mobile Konferenzsysteme, gestellt werden. In dem Kapitel "Stand der Technik" wird eine Auswahl gängiger Whiteboard Module in kommerziellen- sowie nichtkommerziellen Anwendungen präsentiert. Im Anschluß daran werden Anforderungen an ein Whiteboard Modul für den in dieser Arbeit vorgesehenen Einsatzzweck festgelegt. Das Kapitel Grundlagen beschäftigt sich mit den für die Implementierung notwendigen Basistechnologien. Die Entwicklung eines Whiteboard Moduls für mobile Konferenzsysteme wird im darauffolgenden Kapitel beschrieben. Dem schließt sich eine Beispielanwendung an, sowie eine Diskussion der Ergebnisse, die feststellt, ob die Anforderungen erfüllt wurden. Abschließend findet sich ein Ausblick auf zukünftige Erweiterungen.

Volumendaten fallen in unterschiedlichen Bereichen an, beispielsweise bei CT-Scans in der Medizin oder bei Stömungssimulationen im ingenieurstechnischen Bereich. Eine effektive Analyse dieser Daten ist mit der Volumenvisualisierung möglich. Die Integration der Volumenvisualisierung in eine Virtual Reality Umgebung eröffnet die Möglichkeit, einen besseren räumlichen Eindruck sowie eine intuitivere Interaktion mit den dreidimensionalen Volumendaten zu erzielen, als es an Desktop-Systemen möglich ist. Im Rahmen dieser Arbeit wurde zunächst ein Rendermodul entwickelt, das die direkte Volumenvisualisierung mittels 3D-Texturen moderner Graphikhardware umsetzt, um ein echtzeitfähiges Rendering zu ermöglichen. Farbe und Transparenz der Darstellung werden mittels einer zweidimensionalen Transferfunktion aus den Volumendaten bestimmt. Eine interaktive Klassifikation und Beleuchtung wird durch per-Pixel Berechnungen in Fragment-Shader-Programmen der Graphikhardware erreicht. Das Rendermodul wurde in eine VR-Umgebung eingefügt, was die immersive Darstellung eines Volumendatensatzes erlaubt. Es wurde ein Userinterface entwickelt, das die explorative Analyse eines zunächst unbekannten Datensatzes ermöglicht. Schwerpunkt ist die Manipulation der Transferfunktion mit den Eingabegeräten der VR-Umgebung. Ein speziell entwickeltes Widget erlaubt die Visualisierung und Manipulation der Transferfunktion durch ein Höhenmapping-Verfahren. Die räumliche Struktur eines Datensatzes kann durch ein semi-automatischen Klassifikationsverfahren einfach visualisiert werden. Abschliessend wurde die Performanz des entwickelten Systems analysiert und optimiert.

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.

Im Rahmen dieser Diplomarbeit wurde ein System entwickelt, das die globale Analyse von Vektorfeldern auf beliebigen dreidimensionalen Flächen mit unterschiedlichem Detaillierungsgrad ermöglicht. Die Besonderheit liegt dabei an der Fähigkeit, den allgemeinen Fall des Gittertyps, nämlich unstrukturiertes Gitter, zu analysieren. Basierend auf der Idee der Integrate&Draw - Technik in 2D ermöglicht das System die Erzeugung von kontrastreichen Strömungstexturen, die einfacher zu analysieren sind, als es von den LIC- /FastLIC-Bildern bekannt ist. Des weiteren ermöglicht das System die Generierung von Zeitflächen mit den auf ihnen abgebildeten Integrate&Draw-Bildern, die in Verbindung mit der Animation durch die Verformung der Flächen Geschwindigkeitsunterschiede der einzelnen Partikeln deutlich machen. Zusätzlich wurde eine weitere Technik "Oriented Integrate&Draw in 3D auf unstrukturierten Gittern" weiterentwickelt und implementiert, die sich nicht nur durch ihre Geschwindigkeitsvorteile gegenüber dem "Integrate&Draw in 3D auf unstrukturierten Gittern" in Tests auszeichnete, sondern auch durch die Fähigkeiten, dem Beobachter die Richtungsinformationen und die Geschwindigkeitsunterschiede in Verbindung mit Animation vermitteln zu können. Das entwickelte System kann sowohl als Software- aber auch als Hardwarelösung eingesetzt werden. Die Softwarelösung ist plattformunabhängig und kann von dem eigentlichen Visualisierungssystem getrennt werden. Die Hardwarelösung wurde für die NVidia Geforce Chipsätze entwickelt, die über die Fähigkeit verfügen, Vertex-Programme zu verarbeiten. Somit wurde gezeigt, dass die mathematischen Berechnungen von den Grafikkarten mit NVidia Chipsätzen übernommen werden können und die Ergebnisse in effizienter Zeit geliefert werden. Für die Präsentation der Ergebnisse wurde das System in die Virtual Reality Umgebung "IDEFIX" integriert, in der die interaktive Analyse von Vektorfeldern ermöglicht wird. Um die Exploration von Datenmengen so einfach wie möglich zu halten, wurde ein Userinterface entwickelt, mit dem sich die Einflussparameter für die Generierung von Strömungstexturen einfach einstellen lassen.

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

Stelzer, Ralph H. (Ed.) et al.: CAD 2002. Proceedings : Corporate Engineering Research. Bonn: GI, 2002, pp. 271-278

In Modern FActory buildings, nomadic technicians responsible for maintenance or for checking manufacturing state along the production line are often confronted with complex work-pieces and problems, which demand from them high domain knowledge, espsecially to deal with unpredictable occurences. Because these activities are conducted far from office facilities, a portable computer in the toolbox could be very helpful in provide in-hand relevant supporting material. With a wireless communication network, a mobile technician could also remotely access updated product data or process plan, and eventually have a teleconference with a design engineer about the configuration of a machine or a problem in the assembly process. Above all, a positive inclusion of individual expertise, and the integration of post-design activities into a product development process would be achieved, with great prospects for reaching a better product quality and process efficiency. In this paper, an innovative processing and communication apparatus is presented, and software tools for collaboration are described. These tools have been developed within the project MASP with the goal to support the further integration in a developed process. The development challenges concern ergonomic issues raised by the application context, the need of user interfaces aware of users with different abilities and locations, and the performance limitations posed by a wireless mobile platform for the handling of large amounts of data and information.

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

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.

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

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.

ProduktDaten Journal, Vol.9 (2002), 2, pp. 38-41

CAD-CAM REPORT, Vol.21 (2002), 5, pp. 60-63

Business-to-business (B2B) und Collaborative Product Commerce (CPC) sind zur Zeit die treibenden Faktoren im CAx Markt. Dabei steht heute die digitale Produktrepräsentation (digitaler Prototyp) im Mittelpunkt von Geschäftsprozessen und -entscheidungen. Wie bereits im DMU-Umfeld und im Design-Review weitestgehend etabliert, werden heute aufgrund von 3D-CAD Modellen strategische Entscheidungen getroffen. Innovative Präsentations- und Interaktionstechnologien wie Virtual- und Augmented Reality Techniken spielen hier eine zunehmend wichtigere Rolle. Allerdings beschränkt sich deren z.Z. weitestgehend auf den Design Bereich, womit das enorme Potential dieser Technologien bei weitem noch nicht ausgeschöpft ist. Tatsächlich beinhaltet das Engineering eine Vielzahl weiterer Aufgaben die über den reinen Konstruktions- und Designprozeß hinausreichen. Eine besondere Bedeutung kommt der Analyse und Optimierung digitaler und realer Prototypen zu. Numerische Simulationen spielen hierbei eine besondere Rolle und sind heute aus dem täglichen Geschäft des Ingenieurs nicht mehr wegzudenken. Physikalische/Mechanische Problemstellungen werden dabei mit Hilfe numerischer Berechnungs- und Lösungsverfahren bearbeitet. Das Ziel ist dabei zum einen bestehende Produkte zu optimieren und zum anderen eine Vorhersage über vielfältige Eigenschaften neuer Produkte zu treffen. Mit der rasant entwickelten Leistungsfähigkeit und Kapazität aktueller Hardwareumgebungen können mittlerweile neben verschiedene Simulationen auch zahlreiche Messungen in immer kürzeren Zeiträumen und mit steigender Genauigkeit durchgeführt werden. Die Herausforderung stellt sich hierbei in der Verarbeitung, Interpretation und Kommunikation der hieraus resultierenden riesigen Datenmengen. Die Interpretation solch gewaltiger Zahlenkolonnen ist ohne den Einsatz visueller Hilfsmittel heute kaum denkbar. Hieraus ergeben sich die wesentliche Aufgaben und Anforderungen an eine rechnerbasierten Visualisierung. Die Aufgaben bestehen in diesem Umfeld zum Einen in der Unterstützung des Anwenders bei der Generierung von Hypothesen (z.B. bei der Interpretation von Messdaten), deren Validierung sowie in der Kommunikation und schließlich der Präsentation von Ergebnissen. Die Anforderungen ergeben sich zum einen aus der Mächtigkeit und Komplexität der darzustellenden Daten und dem Anspruch an Echtzeitfähigkeit/Interaktionsfähigkeit und Vollständigkeit zum anderen. Durch die Bereitstellung innovativer und interaktiver Visualisierungstechniken kann ein Ingenieur in sinnvoller Weise unterstützt werden. Virtual Reality Techniken ermöglichen es hierbei komplexe Sachverhalte in verständlicher und zeitsparender Form zu validieren und zu präsentieren. Zum gegenwärtigen Zeitpunkt werden die verschiedenen Visualisierungs- und Interaktionstechniken weitestgehend für die Verarbeitung und Analyse bereits abgeschlossener numerischer Simulationen (Post-Processing) genutzt. Auf diese Weise können die Auswirkungen, selbst minimaler Modifikationen, am digitalen Prototypen, erst nach vollständiger Beendigung der Prozesskette, bestehend aus Konstruktion, Vorverarbeitung, Simulation und Visualisierung beurteilt werden. Diese Vorgehensweise ist natürlich sehr Zeitaufwendig zumal sich irrelevante oder fehlerhafte Simulationsverläufe erst am Ende der Prozesskette erkennen lassen. Eine direkte, VR-gestützte Interaktion mit der Simulation bei gleichzeitiger Darstellung der Ergebnisse würde somit enorm zur Verbesserung des gesamten Entwicklungsprozesses beitragen ist daher nach wie vor Gegenstand aktueller Forschungs- und Entwicklungsvorhaben. In diesem Beitrag werden daher die wichtigsten z.Z. eingesetzten interaktiven Methoden und Werkzeuge vorgestellt und ein Ausblick auf weitere innovative Visualisierungstechniken gegeben.

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

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.

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

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.

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

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.

Marjanovic, Dorian (Ed.): Proceedings of the 7th International Design Conference. Zagreb: Faculty of Mecanical Engineering and Naval Architecture, University of Zagreb, 2002, pp. 767-772

Context can be used to define which knowledge should be considered in a virtual reality environment in which a multidisciplinary team will discuss modifications or developments in design, product development, maintenance and production planning. It is desirable that objects within the virtual environment respond according to the context in which they are being used or they are likely to be used. A model of the context can be used as a filter for giving the right meaning to the current context and provide users with a greater control over knowledge. We propose a set of rules that have to be elaborated in order to allow the system to create a model of the context in which a design task is being carried out.

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

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.

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

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.

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.

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).

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.

Krause, Frank-Lothar (Ed.) et al.: iViP: Leitprojekt integrierte Virtuelle Produktentstehung - Abschlussbericht Juni 2002. Stuttgart: Fraunhofer IRB Verlag, 2002, pp. 138-143

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.

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

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.

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

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

IEEE Computer Society: 2001 IEEE Third International Workshop on Networked Appliances. Proceedings : IWNA '01. Singapore, 2001, pp. 7-13

Portable computers and wireless networks have brought a coveted mobility to computer users and have extended the applicability of such tools to a broader range of working activities. Later on, a step forward in terms of availability and usability of these supporting tools has been achieved with Wearable Computers. Nevertheless, the available technologies still pose constrains that compromise the performance and effectiveness of application systems. Besides technological absences, there are important challenges to be solved related to the human-factor and peculiar demands and nature of mobile activities. This article describes an application case involving co-operative work, the system development approach, and a software realization that promote adaptions on a conferencing system according to the resources of the platform and to aspects related to the user and the computer-support task. The target applications are mobile activities such as remote-assisted training, maintenance, or troubleshooting in a factory plant.

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

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.

Korea Society for Simulation (KSS): SeoulSim 2001. Proceedings, pp. 237-247

In this paper we present an overview of existing state of the art visualization techniques for the interactive analysis of results from numerical simulations and measurements. We describe the basic concepts and key ideas behind these different visualization methods in this paper. The potential of these techniques for an efficient integration into a virtual reality environment will be investigated. Furthermore we present our first demonstrator for visualizing multiparametric data and give an outlook on our plans for further exploiting and developing these techniques in an upcoming project.

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

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.

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.

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

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.

International Federation for Information Processing (IFIP): Feature Modeling and Advanced Design-For-The-Life-Cycle Systems. Proceedings 2001. CD-ROM. Valenciennes: Université de Valenciennes, 2001

In this paper the concept of Feature-based Virtual Engineering is presented as an approach to the integrated product development. The focus of the paper is on presenting the current state of our approach towards a feature-based parametric representation of product semantics including a concept for creating and maintaining application specific views on the product information.

ProduktDaten Journal, Vol.8 (2001), 1, pp. 39-41

Studien und die Praxis vieler Ingenieure belegen, dass gerade in der Automobilindustrie bis zu 80% der Konstruktionen Varianten existierender Lösungen sind. Trotzdem ist es noch nicht möglich, die Potenziale der Variantenkonstruktion zur Reduktion der Entwicklungszeiten und damit auch der Entwicklungskosten voll auszunutzen. Die Gründe hierfür sind neben der Schwierigkeit, bestehende Modelle in parametrische Konstruktionen zu überführen, vor allem auch die Restriktionen beim Datenaustausch. Feature-basierte parametrische Modelle können heute neutral nicht zwischen verschiedenen CAx-Systemen ausgetauscht werden. Daher ist es das Ziel dieses Beitrages, die Notwendigkeit eines neutralen STEP- Datenaustausches für "intelligente" Modelle hervorzuheben und auf die Machbarkeit entsprechender Prozessoren hinzuweisen.

Die produzierenden Unternehmen sind durch eine wachsende Produktkomplexität, zunehmende Produktvielfalt und einem steigenden Wettbewerbsdruck gezwungen, neue Wege in der Organisation und in der Unterstützung des Produktentstehungsprozesses zu gehen. Der Produkterprobungsprozeß ist ein Prozeß von zentraler Bedeutung, weil er einen beträchtlichen Anteil der Entwicklungskosten neuer Produkte verursacht. Dabei sind Montage während der Produktion und insbesondere Demontage im Rahmen von Reparatur und Wartung Vorgänge, welche durch den Menschen durchgeführt werden und heute am realen Prototyp einfach zu erproben sind. Demgegenüber ist die Absicherung dieser Vorgänge in einer computerbasierten 3D-Umgebung mit einer Maus-Menü-Schnittstelle keine triviale Aufgabe, weil für die Integration des Menschen keine optimalen Voraussetzungen gegeben sind. Die Eigenschaften der Virtual Reality (VR)-Technologien, wie multidimensionale Interaktionstechniken in Echtzeit stellen eine intuitive Mensch-Maschine-Schnittstelle für solche Absicherungen zur Verfügung. In dieser Arbeit wird die Eignung von VR als Absicherungsmethode für die digitale, manuell gesteuerte Montage und Demontage untermauert.

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

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.

Krause, Frank-Lothar (Ed.) et al.: iViP: Leitprojekt integrierte Virtuelle Produktentstehung - Fortschrittsbericht April 2001. Stuttgart: Fraunhofer IRB Verlag, 2001, pp. 141-144

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

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.

ProductData Journal, Vol.7 (2000), 2, pp. 38-41

A completely computer supported product development process is nowadays regarded as the key to increasing competitiveness. Virtual product development is a new approach to achieving this aim. In this context, virtual refers to continuous digital product development over all phases and across company boundaries and locations. The goal of the main "Integrated Virtual Product Development" (iViP) project sponsored by the Federal Ministry for Education and Research in Germany (BMBF) is therefore the development and introduction into industry of hightech software products for end-to-end virtual product development. This project has been divided up into six thematic project clusters. The projects in clusters 1 and 2 deal mainly with infrastructural foundations for system and data integration within the iViP project as a whole. In other project clusters, cross-industry and cross-company applications are being developed which are based on the results of clusters 1 and 2 and can be integrated in the iViP platform. The virtual test bench is a subproject in cluster 4 (Building and Validation of Virtual Products) and is described in more detail in this article. Detailed information on other subprojects and the iViP project as a whole can be found under [IVIP].

ProduktDaten Journal, Vol.7 (2000), 2, pp. 38-41

Eine durchgehende Digitalisierung des Produktentstehungsprozesses wird heute als der Schlüssel zur Steigerung der Wettbewerbsfähigkeit angesehen. Einen neuen Ansatz auf diesem Weg stellt die Virtuelle Produktentstehung dar. Virtuell bezeichnet hierbei die über alle Phasen durchgängig digitale Produktentstehung über Unternehmensgrenzen und -standorte hinweg. Das Ziel des vom BMBF geförderten Leitprojektes integrierte Virtuelle Produktentstehung (iViP) ist daher die Entwicklung und industrielle Einführung von High - Tech Softwareprodukten für eine vollständige virtuelle Produktentstehung. Thematisch ist diese Projekt in sechs Projektcluster unterteilt. Dabei beschäftigen sich die Projekte der Cluster 1 und 2 vorrangig mit der Erarbeitung infrastruktureller Grundlagen für eine System- und Datenintegration innerhalb des Gesamtprojekts iViP. In weiteren Projektclustern werden branchen- und unternehmesübergreifende Anwendungen entwickelt, welche sich basierend auf den Ergebnissen der Cluster 1 und 2 in die iViP - Plattform integrieren lassen. Der virtuelle Prüfstand ist ein Teilprojekt des Clusters4 "Aufbau und Validierung Virtuelle Produkte" und wird im Folgenden näher beschrieben. Ausführliche Informationen zu weiteren Teilprojekten und zum iViP-Gesamtprojekt sind unter [IVIP] zu finden.

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.

Anderl, Reiner (Ed.) et al.: SMART Engineering. Proceedings : SMART Engineering. Darmstadt: ProSTEP, 2000, pp. 169-180

Virtual reality is the technology for real time visualization of product data within an immersive environment that offers users an intuitive interaction with the model. In the context of virtual product development it is the key technology that allows to minimize the need of physical prototypes. VR provides a suitable digital alternative that allows greater flexibility gaining additional resources for improved quality. Nevertheless, for most VR applications it still requires a lot of effort to adequately prepare CAD data for the needs of a specific target application. Therefore, this paper addresses the problems of VR data acquisition, conversion and preparation within common engineering environments. Requirements to the tools supporting this process chain from PDM to VR are discussed and concepts for fulfilling this requirements are presented. Special interest will be given to the use of the ISO standard STEP.

Computer-Aided Design, Vol.32 (2000), 14, pp. 877-887

Due to the highly complex and informal data that has to be managed in the conceptual design this early design phase still lacks of suitable computer support. Furthermore, existing approaches towards a computer aided conceptual design are insufficiently integrated with the downstream applications of the product development process. The paper therefore introduces an approach towards a feature-based integrated product model that incorporates a feature-based representation scheme for capturing product semantics handled in the conceptual design phase and links early design with part and assembly modelling.

Schützer, Klaus (Ed.): Anais do 5 Seminário Intenacional de Alta Tecnologia : Inovações Tecnológicas no Desenvolvimento do Produto. Piracicaba: UNIMEP, 2000, pp. 83-98

Information technology is more and more used in the product and process development. Especially virtual reality techniques are supporting the man/machine interaction as well as the dialog among the users within the process chain. Co-operation, communication, and co-ordination are calling for support through such techniques to fulfil the requirements of the market in this application area. Modelling with 3D interaction techniques, presentation of simulation results, and virtual environments to experience, analyse, evaluate, and manipulate the products and processes are the major application scenarios today. This paper will introduce to the current state of the art of applying virtual reality techniques to the different aspects of the product development process and give an overview of the corresponding activities at the Fraunhofer-IGD.

Jezernik, Anton (Ed.) et al.: Industrijski Forum 2000. Maribor: Fakulteta zu strojni tvo, 2000, pp. 1/1 - 1/8

Informacijska tehnologija se vedno bolj uveljavlja pri razvoju izdelkov in prozesov. Zlasti vecpredstavnost - multimedija je uporabljena zu podporo dialogu med uporabnikom in strojem, pa tudi pri komunikaciji med uporabniki v procesni verigi. Sodelovanje, komunikacija in koordinacija klicejo po podpori teh tehnologij za izpolnitev zahtev tr i ca. Modeliranje s pomocjo prostorske (3D) interakcije, predstavitev rezultatov simulacij ter navidezna okolja zu poglobljeno do ivljanje, analiziranje, vrednotenje in obdelavo produktov ali procesov so dandanes osrednja podrocja uporabe.

Brunet, Pere (Ed.) et al.: Cad Tools and Algorithms for Product Design. Berlin; Heidelberg; New York: Springer, 2000, pp. 128-150

Zhang, Guangming: Proceedings of the 10th International Conference on Flexible Automation and Intelligent Manufacturing. FAIM 2000. : Proceedings of the Tenth International FAIM Conference. Wheaton, USA: Econo Printing & Graphics, Inc., 2000, pp. 76-85

This paper describes a Teleservice Centre for Design. The System is considered to support an Industrial designer starting at the very early stages of the design process up to the production of the prototype. Special emphasis is placed on the logical architecture of the system. An overview of the provided services and the components of the user interface and an outlook on further work complete this paper.

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

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.

Schmoeckel, Dieter et al.: 7. Umformtechnisches Kolloqium Darmstadt : Anforderungen - Innovationen- Perspektiven. Bamberg: Meisenbach, 2000, pp. 27- 35

Die Informationstechnik wird in der Produkt- und Prozeßentwicklung mehr und mehr eingesetzt. Insbesondere die Multimediatechnologie unterstützt dabei den Dialog des Menschen mit der Maschine aber auch die Kommunikation zwischen den Anwendern in der Prozeßkette. Kooperation, Kommunikation und Koordination bedürfen in diesem Anwendungsfeld einer technologischen Unterstützung, um den Anforderungen des Marktes gerecht zu werden. 3D-Interaktionstechniken zur Modellierung, Aufbereitung von Simulationsergebnissen und Virtuelle Umgenungem zum immersiven Erleben, Analysieren, Bewerten und Bearbeiten der Produkte und Prozesse, sind heute die zentralen Anwendungsbereiche.

Landau, Kurt (Ed.): Ergonomic Software Tools in Product and Workplace Design : A review of recent developments in human modeling and other design aids. Stuttgart: Verlag ERGON GmbH, 2000, pp. 183 - 194

The simulation of human behavior is of crucial importance in the automotive industry to ensure safe and ergonomic vehicle design. Ergonomic analysis based on virtual humans has to be integrated with the techniques of digital mockup and virtual prototyping. Our VIRGO ( Virtual Ergonomic Test Suite) environment can be used for interactive 3D manipulation of the RAMSIS CAD human model and for 3D visualization of data obtained from ergonomic analysis. Both the ergonomic aspects and the related product data from a CAD system are visualized together and interdependencies are shown in an intuitive way. CORBA (Common Object Request Broker Architecture) middleware uses shared onotologies to capture the communication semantics of the individual components and integrate the environment.

Industrie-Management, (2000), 1, pp. 70-75

Neue Techologien setzten sich am Markt nur dann durch, wenn sie dem Anwender langfristig einen Wettbewerbsvorteil beten. Dies gilt insbesondere auch für Virtual Reality (VR), einer Technologie, die erst durch Schaffung wesentlicher Voraussetzungen im Produktentwicklungskontext effizient eingesetz werden kann. Dieser Beitrag gibt einen Einblick in das Konzept des Virtual Engineering und zeigt an konkreten Systemkomponenten, wie VR-Technologie als Komponente von Virtual Engineering innerhalb des Produktentwicklungsprozesses genutzt werden kann.

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.

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

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.

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

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.

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.

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.

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.

The American Society of Mechanical Engineers (ASME): 1999 ASME Design Engineering Technical Conferences. CD-ROM : Design for the next Millenium. New York: The American Society of Mechanical Engineers, 1999, 7 p.

In the modern industrial scenario, the technological assets of new working methods and machinery in factory plants grow rapidly. Nevertheless, a reverse situation occurs in terms of availability of trained personnel within the subject area. Moreover, even the most experienced technician is faced with a continual need to update his/her skills. In respect to the training activities, more realism and a greater effectiveness could be achieved if the trainee could learn a new technology directly in the real working place. In this paper, considerations are presented for the use of an innovative hardware and Augmented Reality as platform components for the learning material to this training scenario. Both components are described with emphasis on their suitability to the target activity. The proposed platform encompasses a body-worn and wireless-networked computer, and software with specific features to assist the computer user in his/her task by enriching the content of the application environment. The software component, which addresses the application goals and required adaptations to the platform, is presented.

Associazione Nazionale Disegno di Macchine (ADM): International Conference on Design Tools and Methods in Industrial Engineering. Session Poster, pp. 153-161

This contribution deals with the application concept of Virtual Engineering (VE), i.e. the application of virtual engineering and communication technology in the product development process. Therefore, requirements of cooperative product development and information and communication technology towards Virtual Engineering are described. Furthermore, applications representing the information technology support for the concept of VE are presented

Jezernik, Anton (Ed.): dmmi '99. Proceedings. Portoroz, 1999, pp. 477-486

Due to highly informal data, which is hard to maintain, the conceptual phase of the design process still lack of computer support. Also, product data management in this phase is weak. This paper presents a proposal for a structured description of a product, applicable in the early phases of the design process, where few geometrical data exist. This description addresses functional structure of product, working principle with effects used in solution and requirements. It is intended to be used for a semantic description of a product, and for storing and retrieving product data based on their functionality.

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

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.

Die zunehmende Globalisierung und Diversifizierung im Produktentstehungsprozeß bedingen den Einsatz von örtlich verteilten Produktentwicklungsteams, die standortübergreifend Entwicklungsprojekte bearbeiten. Eine computer-basierte Unterstützung stellt hierbei die Basis für die Kooperation und Kommunikation dar. Mit dieser Arbeit wird ein integriertes, computer-basiertes Rahmenwerk vorgestellt, das die informationstechnischen Grundlagen für kooperatives Arbeiten in örtlich verteilten Produktentwicklungsteams definiert und die prototypische Umsetzung darlegt. Zielsetzung ist es, eine inhärente Kopplung von Kommunikationsvorgängen mit den ablaufenden Arbeitsprozessen sicherzustellen. Die anwendungsbezogene Visualisierung der Produktdaten stellt hier eine grundlegende Voraussetzung für die Kommunizierbarkeit der Informationen dar. Nur durch auf die Informationsgehalte der Produktdaten abgestimmte Präsentationsformen lassen sich diese an verschiedenen Standorten effizient visualisieren und kooperativ bearbeiten.

Roller, Dieter (Ed.): International Symposium on Automative Technology and Automation. Vol 1. Croydon, England, 1999, pp. 493-500

A perspective for future electronic business in distributed work environments will describe possibilities and requirements to solutions. Global distributed development teams need an internet protocol based network, new user interfaces for telecommunication and integration of their applications into the shared environment. Software agents should support the user in navigation and information management. Collaborative Virtual Environmnets (CVEs) are a combination of virtual reality and multimedia to create a shared environment for human interaction and cooperation. The use of 3D graphics, spatial sound and 3D interaction makes an advanced multidimensional form of telecommunication possible. Virtual Engineering will strengthen the coupling between people, systems and processes via innovative information technology.

Belhi, Abdelkader et al.: Swiss Conference of CAD/CAM '99. Proceedings. Neuchatel, 1999, pp. 25-32

The primary goal of the project ORGTECH is to improve the cooperative work process within and between two design offices and one steel mill through the introduction of 3D CAD and multimedia telecooperation. Introduction of the new technologies takes place intwo cycles based on an inyegrated organization and technology development (OTD) approach. Both cycles will permit the best participation of the users in the development process as apartipatory and evolutionary approach to support changes of work systems. In this paper we describe the organisational and technical problems and first results based on our experience with two pilot teams, '3D CAD' and 'Telecooperation'. The outcome of the first phase, theproblem analysis, is described and followed by a detailed description of the pilot teams. Here modern 3D CAD and telecooperation systems are tailored to the specific situation of the engineer offices and their major customer, the steel mill. We explain the next step of the projectwich consists of introducing the prototypes and organizational change in the pilot teams.

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?

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

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.

IEEE Personal Communications, Vol.5 (1998), 5, pp. 42-46

A form of ubiquitous computing can be achieved with access to the Web from a mobile computing platform, that is, almost unlimited access to worldwide information and services, with no cables confining users to their desks. However, in consideration of this type of user, Web content and service providers have to be aware of the limitations of a wireless platform. Those limitations pose resource and performance values similar to those of the past on the specification demands of the present. In order to prevent a step backward in the content assets of applications, the effects of some constraints of the mobile platform have to be reduced and alternative procedures investigated. In this article, a set of procedures and techniques developed for effective provision and handling of vector graphics and animation contents on a wireless platform is described. It includes granularity reduction of multimedia data, combined handling of media formats, and dynamic generation, plus progressive assembling of service content parts. This work is being realized within a major European project whose main goal is to create the means of providing multimedia services for the Web over mobile computing platforms.

Demonstrating the future wireless information infrastructure. Vol. 1. Athen: Trochos Technical Ed., 1998, pp. 82-89

In the context of multimedia and hypermedia systems, the aspect of including mobile links to a stationary infrastructure and the use of mobile data terminals are gaining increasingly in importance. The current advancements of hardware, software, and telecommunications technology allow multimedia systems to be implemented in mobile environments. Nevertheless, in order to fully reach that goal and to meet the end-users' expectations, specific limitations and usage scenarios of mobile environments have to be taken into consideration. This paper will give a definition of "multimedia" and will describe its major aspects. After presenting these aspects, a scheme for media representation levels is discussed. The main focus in the following parts of the paper is the application of 2D/3D vector graphics and animation for mobile services. The concept of an integrated scene graph and its application in a mobile map service is discussed. The integrated scene graph and its usage as a plugin inside a WWW based browser allows the creation of new, graphics-based services, customized for a mogile platform. The different features introduced by the implementation effort are described, e.g. the overlay and tiling concept, and support for animation on-demand. The plugin is used by the "City Inforamtion Service" which is part or the MOMENTS project (AC002, Mobile Media and ENTertainment Services). Besides the handling of 2D/3D graphics and animation, the plugin allows the specification of different interactions for the mobile user. Besides its use as an enhanced viewer for map material, the plugin concept and its implementaiton can also be adopted for other types of services. For this, different profiles concerning the usage of VRML 2.0, the "Virtual Reality Modeling Language", are taken into consideration. Finally we provide a conclusion and show up direction for future work.

National Museum of Photography, Film & Television, Bradford, UK: From Desktop to Webtop: Virtual Environments on the Internet, WWW and Networks. Bradford, UK, 1997

The factors limiting the efficient delivery and presentation of multimedia material in the cellular environment are, among others, the low bandwidth of the transmission channel(s) and the modest capabilities of truly mobile terminals. The ACTS 1 project MObile Media and ENTertainment Services (MOMENTS) is leveraging the usage of state-of-the-art technique for the handling of vector graphics and animation contents, obtained through very low data transmission channels, in order to provide veru attractive multimedia services in that environment. This paper focuses on the achievements obtained within MOMENTS in regard to the handling of dynamic 2D/3D graphics for the projected wireless multimedia services.