NPH: Natural Phenomena
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Browsing NPH: Natural Phenomena by Subject "Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism"
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Item Effective Multi-resolution Rendering and Texture Compression for Captured Volumetric Trees(The Eurographics Association, 2006) Linz, Christian; Reche-Martinez, Alex; Drettakis, George; Magnor, Marcus; Norishige Chiba and Eric GalinTrees can be realistically rendered in synthetic environments by creating volumetric representations from photographs. However, volumetric tree representations created with previous methods are expensive to render due to the high number of primitives, and have very high texture memory requirements. We address both shortcomings by presenting an efficient multi-resolution rendering method and an effective texture compression solution. Our method uses an octree with appropriate textures at intermediate hierarchy levels and applies an effective pruning strategy. For texture compression, we adapt a vector quantization approach in a perceptually accurate color space, and modify the codebook generation of the Generalized Lloyd Algorithm to further improve texture quality. In combination with several hardware acceleration techniques, our approach achieves a reduction in texture memory requirements by one order of magnitude; in addition, it is now possible to render tens or even hundreds of captured trees at interactive rates.Item Eulerian Motion Blur(The Eurographics Association, 2007) Kim, Doyub; Ko, Hyeong-Seok; D. Ebert and S. MerillouThis paper describes a motion blur technique which can be applied to rendering fluid simulations that are carried out in the Eulerian framework. Existing motion blur techniques can be applied to rigid bodies, deformable solids, clothes, and several other kinds of objects, and produce satisfactory results. As there is no specific reason to discriminate fluids from the above objects, one may consider applying an existing motion blur technique to render fluids. However, here we show that existing motion blur techniques are intended for simulations carried out in the Lagrangian framework, and are not suited to Eulerian simulations. Then, we propose a new motion blur technique that is suitable for rendering Eulerian simulations.Item Realistic Water Volumes in Real-Time(The Eurographics Association, 2006) Baboud, Lionel; Décoret, Xavier; Norishige Chiba and Eric GalinWe present a real-time technique to render realistic water volumes. Water volumes are represented as the space enclosed between a ground heightfield and an animable water surface heightfield. This representation allows the application of recent GPU-based heightfield rendering algorithms. Our method is a simplified raytracing approach which correctly handles reflections and refractions and allows us to render complex effects such as light absorption, refracted shadows and refracted caustics. It runs at high framerates by exploiting the power of the latest graphic cards, and could be used in real-time applications like video games, or interactive simulation.Item Simulating Caustics due to Liquid-Solid Interface Menisci(The Eurographics Association, 2006) Bourque, Eric; Dufort, Jean-François; Laprade, Michelle; Poulin, Pierre; Norishige Chiba and Eric GalinA solid partially immersed in a liquid creates a local deformation of the liquid surface at their interface. This deformation, called a meniscus, exhibits high curvature, and as such, produces very intriguing caustic patterns. However, this natural phenomena has been neglected in almost all previous liquid simulation techniques. We propose a complete solution to model and render meniscal illumination effects. First, we outline a physicallymotivated approach to approximating the geometry of the meniscus. We then describe the targeted photon map, an adapted photon map which facilitates efficient sampling of the finely tessellated menisci. This technique, which integrates well within traditional photon mapping, allows for automatically rendering illumination effects for complex solid-liquid interfaces. Several images rendered using this technique are presented and are compared to their real-world counterparts.