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Progressive Hulls for Intersection Applications
(Blackwell Publishers, Inc and the Eurographics Association, 2003) Platis, Nikos; Theoharis, Theoharis
Progressive meshes are an established tool for triangle mesh simplification. By suitably adapting the simplification process, progressive hulls can be generated which enclose the original mesh in gradually simpler, nested meshes. We couple progressive hulls with a selective refinement framework and use them in applications involving intersection queries on the mesh. We demonstrate that selectively refinable progressive hulls considerably speed up intersection queries by efficiently locating intersection points on the mesh. Concerning the progressive hull construction, we propose a new formula for assigning edge collapse priorities that significantly accelerates the simplification process, and enhance the existing algorithm with several conditions aimed at producing higher quality hulls. Using progressive hulls has the added advantage that they can be used instead of the enclosed object when a lower resolution of display can be tolerated, thus speeding up the rendering process.ACM CSS: I.3.3 Computer Graphics-Picture/Image Generation, I.3.5 Computer Graphics-Computational Geometry and Object Modeling, I.3.7 Computer Graphics-Three-Dimensional Graphics and Realism
The Impulse Graph: A New Dynamic Structure For Global Collisions
(Blackwell Publishers Ltd and the Eurographics Association, 2000) Baciu, George; Keung Wong, Sai
In interactive virtual environments and dynamic simulations, collisions between complex objects and articulated bodies may occur simultaneously at multiple points or regions of interference. Many solutions to the collision response problem are formulated based on the local pair-wise contact dynamics. In this article, we present a new solution to the global interactions and dynamic response between multiple structures in a three-dimensional environment. This is based on a new dynamic impulse graph that tracks the reaction forces through the entire system and gives a global view of all the interactions in a multibody system.
Comparative Visualization of Instabilities in Crash-Worthiness Simulations
(The Eurographics Association, 2001) Sommer, Ove; Ertl, Thomas; David S. Ebert and Jean M. Favre and Ronald Peikert
Since crash-worthiness simulations get more and more important as part of the car development process in order to reduce the cost of development, enhance the product quality, and minimize the time-to-market, the reliability of the simulation results plays a decisive role concerning their significance. Recently the simulation departments of several automotive companies started investigating the quantity and reason for deviations during a number of simulation runs on the same input model. In this case study we discuss different measurements for instability and present a texture-based visualization method which allows the engineers to efficiently explore the simulation results by interactively hiding finite element structures with nearly constant crash performance. Furthermore, we describe those parts of our prototype which use a CORBA layer for providing the same view on a set of simulation results and allowing the visual comparison by using the marker functionality.
Filtered Jitter
(Blackwell Publishers Ltd and the Eurographics Association, 2000) Klassen, R. Victor
Jitter is one popular way of generating samples for stochastic sampling in computer graphics. The Poisson disk distribution better approximates that of the human photomosaic. In this paper we examine the spatial and frequency space behaviour of a number of existing algorithms for generating stochastic samples and propose a new algorithm based on low pass filtering a jittered set of displacements. The distribution is at least as much like that of the human photomosaic as any existing algorithm, while being fast to compute.
Octreemizer: A Hierarchical Approach for Interactive Roaming Through Very Large Volumes
(The Eurographics Association, 2002) Plate, John; Tirtasana, Michael; Carmona, Rhadamés; Fröhlich, Bernd; D. Ebert and P. Brunet and I. Navazo
We have developed a hierarchical paging scheme for handling very large volumetric data sets at interactive frame rates. Our system trades texture resolution for speed and uses effective prediction strategies. We have tested our approach for datasets with up to 16GB in size and show that it works well with less than 500MB of main memory cache for 64MB of 3D-texture memory. Our approach makes it feasible to deal with these volumes on desktop machines.
Effect of visual cues on human performance in navigating through a virtual maze
(The Eurographics Association, 2004) Vembar, D.; Iyengar, N.; Duchowski, A.; Clark, K.; Hewitt, J.; Pauls, K.; Sabine Coquillart and Martin Goebel
Navigation in Virtual Environments (VEs) requires users to develop spatial knowledge of the environment primarily through visual cues provided to the user. Thus, the design and display of visual navigation cues is important for efficient navigation in a VE. In this paper, we report the results of an experiment in which three different visual cues were tested for their benefit toward users' navigation in a 3D virtual maze. The experiment varied the form of visual cue: a 2D map, a 2D map with a directionally ambiguous cue, and a 2D map with a directional cue. Eye tracking data was collected and analyzed to examine the correlation between the type of visual cue presented and the navigational efficiency of the user through the virtual maze. It was observed that the cue type affected performance of the participant in the 3D maze. The directional cue was most effective in the time taken by users to reach the center of the maze. Results of this study have implications for VE design as well as for game development.
An Accurate Illumination Model for Objects Coated with Multilayer Films
(Eurographics Association, 2000) Hirayama, H.; Kaneda, K.; Yamashita, H.; Monden, Y.
This paper proposes an accurate illumination model for rendering objects coated with multilayer films. Optical phenomenaof multilayer films are caused by reflection, refraction, interference, and absorption of light inside each layer of multiple films, and these physical phenomena are complicatedly related with each other. The proposed method calculates composite reflectance and transmittance of multilayer films, taking into account all the physical phenomena described above, and visualizes the optical phenomena caused by the multilayer films accurately. The illumination model proposed in the paper can handle both smooth surface and locally smooth rough surfaces. Several examples of objects coated with various kinds of films demonstrate the usefulness of the proposed method.
On the Evolution of Geometrical Reconstruction as a Core Technology to Sketch-Based Modeling
(The Eurographics Association, 2004) Company, Pedro; Piquer, Ana; Contero, Manuel; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
In this work, the background and evolution of three-dimensional reconstruction of line drawing over the last thirty years is discussed. A new general taxonomy is proposed to describe and discuss the historical evolution of geometrical reconstruction and its challenges. The evolution of geometrical reconstruction from recovering know-how stored in engineering drawings to sketch-based modeling for helping in the first steps of conceptual design purposes, and the current challenges of geometrical reconstruction are also discussed.
Efficient Illumination by High Dynamic Range Images
(The Eurographics Association, 2003) Kollig, Thomas; Keller, Alexander; Philip Dutre and Frank Suykens and Per H. Christensen and Daniel Cohen-Or
We present an algorithm for determining quadrature rules for computing the direct illumination of predominantly diffuse objects by high dynamic range images. The new method precisely reproduces fine shadow detail, is much more efficient as compared to Monte Carlo integration, and does not require any manual intervention.
Resample Hardware for 3D Graphics
(The Eurographics Association, 2002) Meinds, Koen; Barenbrug, Bart; Thomas Ertl and Wolfgang Heidrich and Michael Doggett
Texture mapping is a core technology of current real-time 3D graphics systems. To avoid aliasing artifacts, the texture mapping resample process requires proper filtering. We present a new resample algorithm for twopass forward texture mapping that is suited to an efficient hardware implementation. This method delivers high quality anti-aliased images using filter techniques based on digital signal processing. We use an input sample driven texture resample and filtering algorithm that "splats" the contribution of each input sample (texel) to output samples (pixels). We show how the algorithm can be efficiently implemented in a hardware resample structure. The algorithm is incorporated and tested in a standard 3D graphics pipeline using the OpenGL interface. Our results exhibit better anti-aliasing of textures than anisotropic filtering found in current advanced graphics chips. We also show that the same texture filtering method can be used to implement edge anti-aliasing. Our edge anti-aliasing results show an absence of aliasing on most edges.

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