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Now showing 1 - 10 of 305
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    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.
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    Effective Exercise Instruction System Using Virtual Human
    (The Eurographics Association, 2001) Itami, Yoshikazu; Yoshida, Norimasa; Kitajima, Katsuhiro; J.A.Jorge and N.M.Correia and H.Jones and M.B.Kamegai
    This study aims at developing an aerobics exercise instruction software for personal use by introducing an instruction program best fit to the physical conditions of respective exerciser. The software uses the combination of virtual instructor (virtual human) and Karvonen method in order to develop a comprehensive personal aerobics exercise instruction software. Karvonen method is an algorithm of relationship between the movement of the virtual human and exercise intensity. In this study, its effectiveness is verified and confirmed. The study is mainly focused on the development of synchronization technique between the speed of animation figures' movement for controlling exercise intensity and speed of the sound output, which is the most important technique in the application of the study result into practical use.
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    A Microfacet Based Coupled Specular-Matte BRDF Model with Importance Sampling
    (Eurographics Association, 2001) Kelemen, Csaba; Szirmay-Kalos, Laszlo
    This paper presents a BRDF model based on the analysis of the photon collisions with the microfacets of the surface. The new model is not only physically plausible, i.e. symmetric and energy conserving, but provides other important features of real materials, including the off-specular peak and the mirroring limit case. Using theoretical considerations the reflected light is broken down to a specular component representing single reflections and a matte component accounting for multiple reflections and re-emissions of previously absorbed photons. Unlike most of the previous models, the proportion of the matte and specular components is not constant but varies with the viewing angle. In order to keep the resulting formulae simple, several approximations are made, which are quite accurate but allow for tabulation, fast calculation and even for accurate importance sampling.
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    Valence-Driven Connectivity Encoding for 3D Meshes
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Alliez, Pierre; Desbrun, Mathieu
    In this paper, we propose a valence-driven, single-resolution encoding technique for lossless compression of triangle mesh connectivity. Building upon a valence-based approach pioneered by Touma and Gotsman22 , we design a new valence-driven conquest for arbitrary meshes that always guarantees smaller compression rates than the original method. Furthermore, we provide a novel theoretical entropy study of our technique, hinting the optimality of the valence-driven approach. Finally, we demonstrate the practical efficiency of this approach (in agreement with the theoretical prediction) on a series of test meshes, resulting in the lowest compression ratios published so far, for both irregular and regular meshes, small or large.
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    Real-Time Volume Deformations
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Westermann, Rudiger; Rezk-Salama, Christof
    Real-time free-form deformation tools are primarily based on surface or particle representations to allow for interactive modification and fast rendering of complex models. The efficient handling of volumetric representations, however, is still a challenge and has not yet been addressed sufficiently. Volumetric models, on the other hand, form an important class of representation in many applications. In this paper we present a novel approach to the real-time deformation of scalar volume data sets taking advantage of hardware supported 3D texture mapping. In a prototype implementation a modeling environment has been designed that allows for interactive manipulation of arbitrary parts of volumetric objects. In this way, any desired shape can be modeled and used subsequently in various applications. The underlying algorithms have wide applicability and can be exploited effectively for volume morphing and medical data processing.
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    Volumetric Model Repair for Virtual Reality Applications
    (Eurographics Association, 2001) Kolb, Andreas; John, Lars
    Repairing Virtual Reality (VR) models is a challenge for productive applications. This paper describes a fast implementation of Nooruddin and Turk’s ray-stabbing method 14 based on standard graphics hardware. Raystabbing is used to convert a polygonal model into a volume model (also called voxelization). The volume model is back-converted into a polygonal model using the marching cubes (MC) algorithm 12 and the QSlim algorithm 7 for reducing the extracted polygon model. The overall process yields a properly closed polygonal model with no visual unimportant features like nested or overlapping geometries or unwanted cracks. The voxelization process is the key part of the reparation process. We discuss implementation details and essential problems of ray-stabbing not addressed by Nooruddin and Turk 14.We focus on the generation of the volume model utilizing OpenGL hardware support. The current implementation is a snapshot of an ongoing work at EADS Airbus, Europes leading commercial aircraft company. The final goal is a fast model repair and reduction workflow for generating VR-models and various levels of detail. Problems erase from the fact, that the polygonalization of the volume model using the MC-algorithm generates a far too fine tessellated model which then has to be reduced again. We also discuss possible approaches to overcome this drawback.
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    Combined Rendering of Polarization and Fluorescence Effects
    (The Eurographics Association, 2001) Wilkie, Alexander; Tobler, Robert F.; Purgathofer, Werner; S. J. Gortle and K. Myszkowski
    We propose a practicable way to include both polarization and fluorescence effects in a rendering system at the same time. Previous research in this direction only demonstrated support for either one of these phenomena; using both effects simultaneously was so far not possible, mainly because the techniques for the treatment of polarized light were complicated and required rendering systems written specifically for this task. The key improvement over previous work is that we use a different, more easily handled formalism for the description of polarization state, which also enables us to include fluorescence effects in a natural fashion. Moreover, all of our proposals are straightforward extensions to a conventional spectral rendering system.
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    Deformable Terrain Generation for Real-time Strategy Game
    (Eurographics Association, 2001) Davison, Christopher; Tang, Wen
    In this paper, we present a system that has the ability to deform terrain for Real-time Strategy Game with general PC hardware specifications. Various effects could be simulated in real-time such as raising and lowering the ground, creating a large chasm, or levelling the terrain. Effects such as ordering a unit to fire that then destroys part of a mountain could also be replicated. We present our implementations and techniques in using terrain deformation algorithms, Real-time Optimally Adapting Meshes, texture design and terrain generations. An analysis of the speed and memory usage of the system with respect to different PC hardware systems is also presented.
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    Adaptive Networking for Tele-Immersion
    (The Eurographics Association, 2001) Leigh, Jason; Yu, Oliver; Schonfeld, Dan; Ansari, Rashid; He, Eric; Nayak, Atul; Ge, Jinghua; Krishnaprasad, Naveen; Park, Kyoung; Cho, Yong-joo; Hu, Liujia; Fang, Ray; Verlo, Alan; Winkler, Linda; DeFanti, Thomas A.; B. Froehlich and J. Deisinger and H.-J. Bullinger
    Tele-Immersive applications possess an unusually broad range of networking requirements. As high-speed and Quality of Service-enabled networks emerge, it will becoming more difficult for developers of Tele-Immersion applications, and networked applications in general, to take advantage of these enhanced services. This paper proposes an adaptive networking framework to ultimately allow applications to optimize their network utilization in pace with advances in networking services. In working toward this goal, this paper will present a number of networking techniques for improving performance in tele-immersive applications and examines whether the Differentiated Services mechanism for network Quality of Service is suitable for Tele-Immersion.
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    Volume Rendering in a Virtual Environment
    (The Eurographics Association, 2001) Schulze-Döbold, Jürgen; Wössner, Uwe; Walz, Steffen P.; Lang, Ulrich; B. Froehlich and J. Deisinger and H.-J. Bullinger
    This paper describes a flexible rendering system for scalar volume data which has been integrated into the visualization system COVISE. It allows direct volume rendering based on texture mapping hardware on both the desktop and in projection based virtual environments. Special care has been taken for the design and usability of the virtual reality user interface and for interactive frame rates. It features a new slider-less interaction window for the manipulation of the transfer function and methods for direct interaction with the volume data, such as a sub-volume probing mode. The interface has been evaluated in collaboration with a group of potential end users.