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Now showing 1 - 4 of 4
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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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    Automotive Soiling Simulation Based On Massive Particle Tracing
    (The Eurographics Association, 2001) Roettger, Stefan; Schulz, Martin; Bartelheimer, Wolf; Ertl, Thomas; David S. Ebert and Jean M. Favre and Ronald Peikert
    In the automotive industry Lattice-Boltzmann type flow solvers like PowerFlow from Exa Corporation are becoming increasingly important. In contrast to the traditional finite volume approach PowerFlow utilizes a hierachical cartesian grid for flow simulation. In this case study we show how to take advantage of these hierarchical grids in order to extend an existing Lattice-Boltzmann CFD environment with an automotive soiling simulation system. To achieve this, we chose to constantly generate a huge number of massive particles in user manipulable particle emitters. The process of tracing these particles step by step thus creates evolving particle streams, which can be displayed interactively by our visualization system. Each particle is created with stochastically varying diameter, specific mass and initial velocity, whereas already existing particles may decay because of aging, when leaving the simulation domain or when colliding with the vehicle s surface. On the one hand the display of these animated particles is a very natural and intuitive way to explore a CFD data set. On the other hand animated massive particles can be easily utilized for driving an automotive soiling simulation just by coloring the particles hit points on the vehicle s surface.
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    High-Quality Pre-lntegrated Volume Rendering
    (The Eurographics Association, 2001) Engel, Klaus; Kraus, Martin; Ertl, Thomas; Kurt Akeley and Ulrich Neumann
    We introduce a novel texture-based volume rendering approach that achieves the image quality of the best post-shading approaches with far less slices. It is suitable for new flexible consumer graphics hardware and provides high image quality even for low-resolution volume data and nonlinear transfer functions with high frequencies, without the performance overhead caused by rendering additional interpolated slices. This is especially useful for volumetric effects in computer games and professional scientific volume visualization, which heavily depend on memory bandwidth and rasterization power. We present an implementation of the algorithm on current programmable consumer graphics hardware using multi-textues with advanced texture fetch and pixel shading operations. We implemented direct volume rendering, volume shading, arbitrary number of isosurfaces, and mixed moder endering. The performance does neither depend on the number of isosurfaces nor the definition of the transfer functions, and is therefore suited for interactive highquality volume graphics.
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    Topology-Guided Downsampling
    (The Eurographics Association, 2001) Kraus, Martin; Ertl, Thomas; K. Mueller and A. Kaufman
    We present a new downsampling method for structured volmue grids, which preserves much more of the topology of a scalar field than existing downsampling methods by preferable selecting scalar values of critical points. In particular, many critical points can be preserved which are lost by traditional downsampling methods. Our method is named 'topology-guided downsampling' as topology-preserving downsampling is impossible in general. However, we show that even an approximate preservation of topology is highly desirabel if isosurfaces are extracted from the downsampled volume grid, e.g. for interactive pre-viewing, because many topological features of the isosurfaces, e.g. the number of components, tunnels, and holes, are preserved. We illustrate the benefits of our method with examples from medical and technical applications of volume visualization.