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Hafner, Morris; Kuijper, Arjan (Betreuer); Limper, Max (Betreuer)

Robust and Efficient Bijective Parameterization

2017

Darmstadt, TU, Bachelor Thesis, 2017

The goal of this thesis was to create a novel algorithm for bijective parameterizations of 3D triangle meshes with disk topology. Existing methods are either fast, but create non-bijective parameterizations, or are too slow to be applied to bigger meshes like high-resolution 3D scans or video game levels. We show an approach to transform an arbitrary, potentially non-bijective parameterization into a bijective mapping. The results show that the new algorithm produces results that are at least competitive with existing bijective parameterizers and still has room for future improvements.

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Berkei, Sarah; Kuijper, Arjan (Betreuer); Limper, Max (Betreuer)

Effiziente und Vollautomatische Grobausrichtung für den Soll-Ist-Abgleich zwischen CAD-Modellen und Scandaten

2016

Darmstadt, TU, Master Thesis, 2016

Diese Arbeit befasst sich mit der Entwicklung und anschließenden Evaluation eines globalen Registrierungsverfahren zum Soll-Ist-Abgleich zwischen Scandaten und einem CAD-Modell. Dabei liegt der Fokus auf einer effizienten Ausrichtung der Daten zueinander, die schneller als ein manuelles Vorgehen ist. Als Grundlage dient der "4-Point Congruent Sets" Algorithmus, der die Transformation zwischen zwei Punktwolken zueinander berechnet. Im Rahmen dieser Arbeit wird er mit einem klassischen, auf den Anwendungsfall der Arbeit angepassten, Ansatz "RANSAC-based DARCES" evaluiert. Darüber hinaus werden das "Largest Common Pointset" und die "Hausdorff-Distanz" als Bewertungskriterien verglichen, um eine möglichst effiziente und genaue Registrierung zu erreichen. Um das Ergebnis der globalen Registrierung zu bewerten, wird der "Iterative Closest Point" Algorithmus in die globale Registrierung integriert. Zu erkennen ist, dass 4PCS, vor allem auf strukturreichen Oberflächen, mit diesem Ansatz in durchschnittlich 5,5 Sekunden bis zu 74% zuverlässige Ergebnisse liefert. Auf strukturarmen Oberflächen kann mittels des "RANSAC-based DARCES" bis 82% valide Ergebnisse erzielt werden, wobei die Zeit für die Berechnung mit den verwendeten Testmodellen durchschnittlich unter 4 Sekunden lag.

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Limper, Max; Kuijper, Arjan; Fellner, Dieter W.

Mesh Saliency Analysis via Local Curvature Entropy

2016

Santos, Luis Paulo (Ed.) et al.: Eurographics 2016. Short Papers. The Eurographics Association, 2016, pp. 13-16

Annual Conference of the European Association for Computer Graphics (Eurographics) <37, 2016, Lisbon, Portugal>

We present a novel approach for estimating mesh saliency. Our method is fast, flexible, and easy to implement. By applying the well-known concept of Shannon entropy to 3D mesh data, we obtain an efficient method to determine mesh saliency. Comparing our method to the most recent, state-of-the-art approach, we show that results of at least similar quality can be achieved within a fraction of the original computation time. We present saliency-guided mesh simplification as a possible application.

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Limper, Max; Brandherm, Florian; Fellner, Dieter W.; Kuijper, Arjan

Evaluating 3D Thumbnails for Virtual Object Galleries

2015

ACM SIGGRAPH: Proceedings Web3D 2015 : 20th International Conference on 3D Web Technology. New York: ACM, 2015, pp. 17-24

International Conference on 3D Web Technology (WEB3D) <20, 2015, Heraklion, Crete, Greece>

Virtual 3D object galleries on the Web nowadays often use realtime, interactive 3D graphics. However, this does usually still not hold for their preview images, sometimes referred to as thumbnails. We provide a technical analysis on the applicability of so-called 3D thumbnails within the context virtual 3D object galleries. Like a 2D thumbnail for an image, a 3D thumbnail acts as a compact preview for a real 3D model. In contrast to an image series, however, it enables a wider variety of interaction methods and rendering effects. By performing a case study, we show that such true 3D representations are, under certain circumstances, even able to outperform 2D image series in terms of bandwidth consumption. We thus present a complete pipeline for generating compact 3D thumbnails for given meshes in a fully automatic fashion.

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Behr, Johannes; Mouton, Christophe; Parfouru, Samuel; Champeau, Julien; Jeulin, Clotilde; Thöner, Maik; Stein, Christian; Schmitt, Michael; Limper, Max; Sousa, Miguel de; Franke, Tobias; Voss, Gerrit

webVis/instant3DHub - Visual Computing as a Service Infrastructure to Deliver Adaptive, Secure and Scalable User Centric Data Visualisation

2015

ACM SIGGRAPH: Proceedings Web3D 2015 : 20th International Conference on 3D Web Technology. New York: ACM, 2015, pp. 39-47

International Conference on 3D Web Technology (WEB3D) <20, 2015, Heraklion, Crete, Greece>

This paper presents the webVis / instant3DHub platform, which combines a novel Web-Components based framework and a Visual Computing as a Service infrastructure to deliver an interactive 3D data visualisation solution. The system focuses on minimising resource consumption, while maximising the end-user experience. It utilises an adaptive and automated combination of client, server and hybrid visualisation techniques, while orchestrating transmission, caching and rendering services to deliver structural and semantically complex data sets on any device class and network architecture. The API and Web Component framework allow the application developer to compose and manipulate complex data setups with a simple set of commands inside the browser, without requiring knowledge about the underlying service infrastructure, interfaces and the fully automated processes. This results in a new class of interactive applications, built around a canvas for real-time visualisation of massive data sets.

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Brandherm, Florian; Kuijper, Arjan (Betreuer); Limper, Max (Betreuer)

Automatic Appearance-Preserving Generation of Compact 3D Models for the Web

2014

Darmstadt, TU, Bachelor Thesis, 2014

The goal of this thesis was to create a fully automatic processing pipeline to simplify big arbitrary triangle meshes to a degree that can be used inside a web page using WebGL. While the mesh complexity is decreased by orders of magnitude, the original meshes details (e.g. colors, normals) are preserved by capturing them in textures. These textures can then be applied to the simplified mesh to give it an appearance that is similar in detail as the original high resolution mesh. The proposed implementation makes it easy to incorporate such a simplified mesh into a website by providing an exporter that generates a web site with all necessary files in suitable file formats. Simplified, detail-preserving 3D models are generated in multiple independent steps: First, the mesh is simplified with the quadric edge collapse algorithm[9]. Then, a texture atlas is created by segmenting the simplified mesh and parameterizing the individual segments with Least Squares Conformal Maps[14]. After packing the individual segments into a texture atlas, the details of the high-resolution input mesh are captured in textures. At the end of this processing pipeline, the model is exported. The results show that the goal of creating file sizes that are small enough for a web page while preserving a reasonable amount of detail was reached. It is shown that the resulting files can compete with the alternative approach of creating interactive 3Dvisualizations with a series of pre-rendered images. The analysis of the results also shows that there is a lot of potential to increase the file size to detail ratio further.

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Mouton, Christophe; Parfouru, Samuel; Jeulin, Clotilde; Dutertre, Cecile; Goblet, Jean-Louis; Paviot, Thomas; Lamouri, Samir; Limper, Max; Stein, Christian; Behr, Johannes; Jung, Yvonne

Enhancing the Plant Layout Design Process using X3DOM and a Scalable Web3D Service Architecture

2014

Polys, Nicholas F. (General Chair) et al.: Proceedings Web3D 2014 : 19th International Conference on 3D Web Technology. New York: ACM, 2014, pp. 125-132

International Conference on 3D Web Technology (WEB3D) <19, 2014, Vancouver, BC, Canada>

This paper presents an innovative model-driven architecture enabling 3D web-based design processes in the field of large complex building (LBC) projects, such as power plant construction. This work was motivated by proposing new ways of achieving 3D CAD tasks not only for highly complex and temporary organization in the design stages but also for the whole lifecycle of such installations, which may last several decades. in this particular scenario, it is very important to share the right information with the right stakeholder at the right time, to maintain a high level of knowledge sharing. Taking into account these challenges, we propose a first implementation of interactive 3D CAD editing tools, based on the X3DOM technology and driven by a knowledge layer which utilizes a complete reference data and rules management system. To store the CAD models, a Macro-Parametric Approach has been investigated and a 3D server has been added to the traditional PDM (Product or Plant Data Management) to execute remotely complex CAD operations. This is a very promising start to deploy lightweight and smart web3D CAD editing services for the AEC (Architecture Engineering Construction) and power industries.

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Stein, Christian; Limper, Max; Kuijper, Arjan

Spatial Data Structures for Accelerated 3D Visibility Computation to Enable Large Model Visualization on the Web.

2014

Polys, Nicholas F. (General Chair) et al.: Proceedings Web3D 2014 : 19th International Conference on 3D Web Technology. New York: ACM, 2014, pp. 53-61

International Conference on 3D Web Technology (WEB3D) <19, 2014, Vancouver, BC, Canada>

The visualization of massive 3D models is an intensively examined field of research. Due to their rapidly growing complexity of such models, visualisation them in real-time will never be possible through a higher speed of rasterization alone. Instead, a practical solution has to reduce the amount of data to be processed, using a fast visibility determination. In recent years, the combination of Javascript and WebGL raised attention for the possibility of rendering hardware-accelerated 3D graphics directly in the browser. However, when compared to desktop applications, they are still fighting with their disadvantages of a generally slower execution speed, or a downgraded set of functionality. We demonstrate the integration of spatial data structures, computed on the client side, using latest technology trends to mitigate the shortcomings of the 3D Web environment. We employ comparably small bounding volume hierarchies to accelerate our visibility determination, as well as to enable specific culling techniques. This allows for an interactive visualization of such massive 3D data sets. Our in-depth analysis of different data structures and environments shows which combination of data structure and visibility determination techniques are currently the best fit for the Web.

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Limper, Max; Thöner, Maik; Behr, Johannes; Fellner, Dieter W.

SRC - A Streamable Format for Generalized Web-based 3D Data Transmission

2014

Polys, Nicholas F. (General Chair) et al.: Proceedings Web3D 2014 : 19th International Conference on 3D Web Technology. New York: ACM, 2014, pp. 35-43

International Conference on 3D Web Technology (WEB3D) <19, 2014, Vancouver, BC, Canada>

A problem that still remains with today's technologies for 3D asset transmission is the lack of progressive streaming of all relevant mesh and texture data, with a minimal number of HTTP requests. Existing solutions, like glTF or X3DOM's geometry formats, either send all data within a single batch, or they introduce an unnecessary large number of requests. Furthermore, there is still no established format for a joined, interleaved transmission of geometry data and texture data. Within this paper, we propose a new container file format, entitled Shape Resource Container (SRC). Our format is optimized for progressive, Web-based transmission of 3D mesh data with a minimum number of HTTP requests. It is highly configurable, and more powerful and flexible than previous formats, as it enables a truly progressive transmission of geometry data, partial sharing of geometry between meshes, direct GPU uploads, and an interleaved transmission of geometry and texture data. We also demonstrate how our new mesh format, as well as a wide range of other mesh formats, can be conveniently embedded in X3D scenes, using a new, minimalistic X3D ExternalGeometry node.

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Bockholt, Ulrich; Behr, Johannes; Wagner, Sebastian; Limper, Max; Olbrich, Manuel; Franke, Tobias

VR/AR-Technologien im Browser: Effiziente Integration virtueller Technologien ins PDM-Umfeld durch Nutzung von Web-Technologien

2014

Schenk, Michael (Ed.): 17. IFF-Wissenschaftstage 2014. Tagungsband : Digitales Engineering zum Planen, Testen und Betreiben technischer Systeme, pp. 103-108

IFF-Wissenschaftstage <17, 2014, Magdeburg, Germany>

Die Verknüpfung von Web-Technologien und VT-Technologien ermöglicht es, sehr schnell und sehr effizient, schlanke und aufgabenspezifischen Anwendungen zu entwickeln, die über HTML-Interfaces auf PDM-Systeme zugreifen. Diese Anwendungen können gut gewartet, modifiziert und erweitert werden, weil für die Anpassung lediglich HTML-Kenntnisse benötigt werden. Durch die vorgestellten Technologien können Virtual und Augmented Reality Technologien in den Web-Browser gebracht werden und Interfaces können geschaffen werden, durch die VR/AR direkt auf PDM Daten zugreifen kann. Damit können die Workflows in industriellen Anwendungen unterstützt werden und die Akzeptanz der Technologien kann in den Unternehmen gestärkt werden.

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Schwenk, Karsten; Voss, Gerrit; Behr, Johannes; Jung, Yvonne; Limper, Max; Herzig, Pasquale; Kuijper, Arjan

Extending a Distributed Virtual Reality System with Exchangeable Rendering Back-Ends

2013

The Visual Computer, Vol.29 (2013), 10, pp. 1039-1049

We present an approach to integrate multiple rendering back-ends under a common application layer for distributed systems. The primary goal was to find a practical and nonintrusive way to use potentially very different renderers in heterogeneous computing environments without impairing their strengths and without burdening the back-ends or the application with details of the cluster environment. Our approach is based on a mediator layer that handles multithreading, clustering, and the synchronization between the application's and the back-end's scene. We analyze the proposed approach with an implementation for a state-of-the- art distributed VR/AR system. In particular, we present two case studies and an example application.

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Jung, Yvonne; Limper, Max; Herzig, Pasquale; Schwenk, Karsten; Behr, Johannes

Fast and Efficient Vertex Data Representations for the Web

2013

Coquillart, Sabine (Ed.) et al.: GRAPP 2013 - IVAPP 2013 : Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications. SciTePress, 2013, pp. 601-606

International Conference on Computer Graphics Theory and Applications (GRAPP) <8, 2013, Barcelona, Spain>

Supporting decision processes via fast and accurate visualization of 3D data is an important aspect in many scientific fields, ranging from mathematics and engineering trough medical data analysis. Due to their high flexibility and platform-independence, 3D Web technologies have become more and more important for such visualization purposes. Within this paper, we concentrate on the accurate rendering of 3D surface models inside Web browsers and show efficient techniques that enable fast and precise visualization and interaction using state-of-the-art Web technologies. We introduce a smart vertex data storage format, which fits very well with the requirements of modern mobile graphics hardware. Furthermore, we discuss methods to partition models of high complexity. Finally, we present an hardware-accelerated picking algorithm that enables a high precision inspection of 3D objects and their vertex attributes.

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

Fast Delivery of 3D Web Content: A Case Study

2013

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

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

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

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Limper, Max; Jung, Yvonne; Behr, Johannes; Sturm, Timo; Franke, Tobias; Schwenk, Karsten; Kuijper, Arjan

Fast, Progressive Loading of Binary-Encoded Declarative-3D Web Content

2013

IEEE Computer Graphics and Applications, Vol.33 (2013), 5, pp. 26-36

The encoding of scene-graph related structured data along with unstructured vertex data within the same descriptive elements of a scene is a major drawback of XML based model formats (such as X3D or Collada) and declarative 3D approaches. Web browsers have to download the complete scene before being able to further process the structure of the document. By introducing Sequential Image Geometry (SIG) containers and explicit binary containers we were able to overcome this limitation. They are wellaligned to buffer structures on the GPU, enabling fast decoding and GPU upload. We improve the image-based approach significantly and introduce a new method called Progressive Binary Geometry (PBG) which enables a simple yet highly progressive transmission of arbitrary mesh data.

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Maushagen, David; Limper, Max (Betreuer)

Hochperformante Szenengraphentraversierung in webbasierten Umgebungen zur Bildgenerierung

2013

Emden-Leer, Hochschule, Master Thesis, 2013

Optimierungsverfahren wie das Transformation Caching, das View Frustum Culling oder das State Sorting, die mit Hilfe des Szenengraphenkonzepts für eine Verbesserung der Leistung von 3D-Applikationen sorgen, können auch in webbasierten Umgebungen im Kontext von WebGL eingesetzt werden. Mit der Komplexität der Szenen steigt jedoch auch der notwendige Optimierungsaufwand, der in unterschiedlichen Anwendungsbereichen die Effizienz der Optimierungsverfahren beeinflussen kann. Die vorliegende Arbeit analysiert die Effizienz der Optimierungsverfahren in verschiedenen Anwendungsfällen und Situationen. Die Optimierungsverfahren erzielen in den meisten Szenarien einen Gewinn. Der Verlust der in ihren Worst Case Szenarien auftritt ist hingegen sehr gering. Der gemeinsame Einsatz der Optimierungsverfahren kann dabei nicht nur Verluste eines Optimierungsverfahrens durch den Gewinn eines anderen kompensieren, sondern in einigen Fällen zu einem größeren Gewinn führen.

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Kordek, Andres Felipe; Limper, Max (Betreuer); Kuijper, Arjan (Betreuer)

Intuitive Platzierung von Objekten in webbasierten CAD-Umgebungen

2013

Darmstadt, TU, Bachelor Thesis, 2013

Diese Bachelorarbeit vergleicht durch eine Benutzerevaluation die Usability zweier Ansätze des Snappings. Ein während der Arbeit entstandener Editor soll als Testumgebung dienen. Die Arbeit ist in mehrere Abschnitte unterteilt. Vorab findet eine kurze Einführung über den Editor und die dafür verwendeten Technologien statt. Im darauf folgenden Abschnitt werden verwandte Dokumentationen angesprochen und es findet eine kurze Einführung über die mathematischen Hintergründe in der Computergrafik statt. Als nächstes folgt die Implementierung und die genauere Beschreibung beider Ansätze. Abschließend werden beide Implementierungen durch eine Benutzerevaluation auf ihre Usability getestet und miteinander verglichen. Zum Schluss werden die Ergebnisse ausgewertet und daraus wird zu allerletzt ein Fazit gezogen.

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Stein, Christian; Kuijper, Arjan (Betreuer); Limper, Max (Betreuer)

Spatial Data Structures for Efficient Visualization of Massive 3D Models on the Web: Räumliche Datenstrukturen zur effizienten Visualisierung riesiger 3D-Modelle im Web

2013

Darmstadt, TU, Master Thesis, 2013

The visualization of massive 3d models, mostly CAD data, consisting of several millions of triangles is still an intensively examined field of research. Compared to the constant performance increase of 3d graphics cards, their complexity grows even faster. Therefore, the problem of rendering such models at an interactive framerate is not to be solved by a higher speed of rasterization all alone. Recently, the combination of Javascript and WebGL gained a lot of attention for the possibility of using hardware acceleration when rendering 3d graphics directly in the browser. However, due to these technologies' limitations of a generally way slower execution speed or a downgraded set of functionality, the previously stated problem gets intensified when transfered to the web environment. A practical solution has to shrink the amount of data to be processed by an intelligent selection. This thesis addresses the application area of Just-In-Browser visualization of these kinds of 3d models. Therefore, spatial data structures and hardware supported visibility determination are evaluated for their applicability and benefit in the web context. To allow for an instant viewing, any time-consuming optimizations are spared. In return, a decrease in correctness of the generated images is accepted. The possibly unstructured scene data is transformed into an optimized representation which employs the spatial data structures in the process of visibility determination. A selection of spatial data structures and culling techniques are evaluated across different environments. Additionally, a feedback controlled adjustment for the culling parameters is introduced.

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Limper, Max; Jung, Yvonne; Behr, Johannes; Alexa, Marc

The POP Buffer: Rapid Progressive Clustering by Geometry Quantization

2013

Computer Graphics Forum, Vol.32 (2013), 7, pp. 197-206

Pacific Conference on Computer Graphics and Applications (PG) <21, 2013, Singapore>

Within this paper, we present a novel, straightforward progressive encoding scheme for general triangle soups, which is particularly well-suited for mobile and Web-based environments due to its minimal requirements on the client's hardware and software. Our rapid encoding method uses a hierarchy of quantization to effectively reorder the original primitive data into several nested levels of detail. The resulting stateless buffer can progressively be transferred as-is to the GPU, where clustering is efficiently performed in parallel during rendering. We combine our approach with a crack-free mesh partitioning scheme to obtain a straightforward method for fast streaming and basic view-dependent LOD control.