NPH07: Natural Phenomena 2007

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https://diglib.eg.org/handle/10.2312/410

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Browsing NPH07: Natural Phenomena 2007 by Title

Now showing 1 - 9 of 9
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    Animating Corrosion and Erosion
    (The Eurographics Association, 2007) Wojtan, Chris; Carlson, Mark; Mucha, Peter J.; Turk, Greg; D. Ebert and S. Merillou
    In this paper, we present a simple method for animating natural phenomena such as erosion, sedimentation, and acidic corrosion. We discretize the appropriate physical or chemical equations using finite differences, and we use the results to modify the shape of a solid body. We remove mass from an object by treating its surface as a level set and advecting it inward, and we deposit the chemical and physical byproducts into simulated fluid. Similarly, our technique deposits sediment onto a surface by advecting the level set outward. Our idea can be used for off-line high quality animations as well as interactive applications such as games, and we demonstrate both in this paper.
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    Convective Clouds
    (The Eurographics Association, 2007) Geist, Robert; Steele, Jay; Westall, James; D. Ebert and S. Merillou
    A new technique for rendering convective clouds is suggested. The technique uses two lattice-Boltzmann (LB) models, one for generating the spatial and temporal distribution of water density and the other for photon transport, that is, lighting the water density with correct anisotropic scattering. The common LB structure is easily mapped to parallel execution environments such as a GPU or multiple CPUs connected via the Message Passing Interface (MPI), thereby providing sub-minute execution times on commodity hardware.
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    Eulerian Motion Blur
    (The Eurographics Association, 2007) Kim, Doyub; Ko, Hyeong-Seok; D. Ebert and S. Merillou
    This 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.
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    Expressive Illumination of Foliage Based on Implicit Surfaces
    (The Eurographics Association, 2007) Luft, Thomas; Balzer, Michael; Deussen, Oliver; D. Ebert and S. Merillou
    This paper presents an approach for vivid representations of foliage based on implicit surfaces. It approximates the complex lighting interaction within the foliage and enables a clear illustration of its general shape and local density, thus supporting the three-dimensional depth cue of the viewer. Due to its straightforward implementation as a preprocessing step that only adjusts the normal vectors of the geometry, this method has no additional memory requirements during the rendering process, and is especially applicable to real-time visualizations.
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    Fast Fluid Simulation Using Residual Distribution Schemes
    (The Eurographics Association, 2007) Sewall, Jason; Mecklenburg, Paul; Mitran, Sorin; Lin, Ming; D. Ebert and S. Merillou
    We present a fast method for physically-based animation of fluids on adaptive, unstructured meshes. Our algo- rithm is capable of correctly handling large-scale fluid forces, as well as their interaction with elastic objects. Our adaptive mesh representation can resolve boundary conditions accurately while maintaining a high level of efficiency.
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    Goblins by Spheroidal Weathering
    (The Eurographics Association, 2007) Beardall, Mathew; Farley, Mckay; Ouderkirk, Darius; Smith, Jeremy; Jones, Michael; Egbert, Parris; D. Ebert and S. Merillou
    Height map models of terrain are computationally efficient but can not represent terrain with concave surfaces. We present an algorithm for generating sandstone goblins using a simulation of spheroidal weathering. Sandstone goblins are a kind of hoodoo which are characterized by rounded concave shapes. The weathering simulation uses bubbles centered on axis aligned voxels to approximate geometry-dependent effects of spheroidal weathering. We demonstrate that the algorithm, together with appropriate surface textures, produces visually plausible goblins at near interactive speeds for most simulation parameters.
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    Modeling Trees with a Space Colonization Algorithm
    (The Eurographics Association, 2007) Runions, Adam; Lane, Brendan; Prusinkiewicz, Przemyslaw; D. Ebert and S. Merillou
    We extend the open leaf venation model by Runions et al. [RFL*05] to three dimensions and show that it generates surprisingly realistic tree structures. Model parameters correspond to visually relevant tree characteristics identified in landscaping, offering convenient control of tree shape and structure.
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    Multi-layered Indirect Texturing for Tree Rendering
    (The Eurographics Association, 2007) García, Ismael; Patow, Gustavo; Szirmay-Kalos, László; Sbert, Mateu; D. Ebert and S. Merillou
    This paper presents a technique to render in real time complex trees using billboard clouds as an impostor simplification for the original polygonal tree, combined with a new texture-based representation for the foliage. The technique provides several new contributions with respect to previous approaches. The new algorithm allows progressive level of detail both at the geometric and at the shader levels. It also preserves the parallax effects of the original polygonal model keeping leaf positions, orientations, and preserving the overlapping of the leaves as seen from any view point. In addition, the texture-based representation provides high-definition close views without introducing high memory requeriments. We adapted a realistic lighting model with soft shadows and a global illumination precomputation, allowing to render highly complex scenes with thousands of trees in real time.
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    Real-time Rendering and Animation of Plentiful Flames
    (The Eurographics Association, 2007) Bridault, Flavien; Leblond, Michel; Rousselle, François; Renaud, Christophe; D. Ebert and S. Merillou
    Rendering and animating flames in real time is a great challenge because of the complexity of the combustion process. While few models succeeded in simulating a single fire in real time, none tried to handle a large number of flames. In this paper we propose a set of techniques which aim at handling numerous flames like those of candles, torches or campfires in real time. We manage different levels of accuracy in the simulation, which is based on a fast fluid dynamics solver. We also consider many optimizations to reduce the rendering cost of a single flame. As a result, our approach is able to animate and render dozens of realistic flames in real-time, each one reacting independently to forces introduced at the scene level.