NBC News Scripts
WBAP-TV (Television station : Fort Worth, Tex.)
1954-12-31
Search results
223 records were found.
Réalisé en cotutelle avec l'Université de Grenoble.
Plusieurs problèmes difficiles dans le domaine de l'animation d'objets déformables peuvent être résolus en combinant les modèles existants avec des surfaces implicites. Utilisées pour habiller une structure en mouvement, ces dernières détectent les collisions, modélisent les déformations locales qui en résultent, et transmettent les forces de réponse à la structure interne. Elles peuvent également contrôler les variations de volume de l'objet à animer. Nous présentons plusieurs applications, allant de l'animation de formes organiques à la simulation de substances hautement déformables.
How can Implicit Surfaces be used in the context of high-end Computer Animation ? This paper compares two different representations of field functions – the constructive approach and the field image approach. Their respective advantages and limitations for the definition of animation and morphing algorithms, and for the visualization of an animation are discussed. We show that efficient solutions to the animation of textured objects can be provided by hybrid methods that combine these representations together and/or with parametric surfaces. This point is illustrated by two case studies: the animation of deformable characters and the simulation of textured lava-flows.
This paper presents an implicit deformable model, based on isosurfaces of potential fields generated by skeletons, that provides elegant and unified formulations for both geometric parameters such as shape or deformation and physical properties such as rigidity. The model is especially designed to improve collision and contact processing for non-rigid objects. In particular, it generates and maintains exact contact surfaces during interactions.
Qui n'a pas rêvé d'être Dieu? De créer le monde, "son" monde, de le contrôler et de l'explorer librement? Les nouvelles technologies de l'image nous propulsent dans cette voie. Parfois munis de dispositifs d'immersion - vision en relief, son spatialisé, dispositifs tactiles et même olfactifs, animés pour donner l'illusion de la vie, les mondes virtuels nous permettent d'exprimer librement notre force créatrice. Ce texte situe dans un premier temps les techniques à mettre en oeuvre pour la création de mondes virtuels, ainsi que les enjeux de ces derniers pour notre société. Nous mettons en évidence le verrou scientifique que constitue l'extrême complexité des scènes et des phénomènes à reproduire. Nous montrons, sur l'exemple des scènes naturelles animées, que l'emploi d'une méthodologie adaptée permet de lever en partie ces dificcultés...
Traditional animation systems are based on key-frames, which are a succession of individual states (the position, orientation, and current shap of objects) specified by an animator. This often requires a tedious application of specialized knowledge and intuition. Physically based animation has been of interest in recent years because it permits the automation of many of these tasks. Its basic goal is to to generate the motion, articulation, and deformation of objects over time from initial conditions and a set of externally applied force. Of particular interest here, physically based systems can automatically detect and respond to collisions and thus are especially suitable for simulating deformable objects. Such systems can either be used alone for the simulation of inanimate objects or in combination with lifelike behaviors, as has b...
This report presents an approach for efficiently yet precisely simulating highly deformable substances ranging from solids to liquids. The key idea is to use a state equation for specifying the dynamics of the substance. During a simulation, the material is sampled by particles that derive their interaction forces from this state equation. Since this ensures the same qualitative behavior whatever the discretization rate, an adaptive scheme can be used during simulations: the particle system adapts over space and time according to a given compromise between precision and computati- onal efficiency. The system refines (i.e., particles are subdivided) in areas undergoing large or fast deformations, while it simplifies (i.e., neighboring particles are merged) in stable regions. Meanwhile, the values of the individual integration time steps...
Generation of dynamic natural scenes is essential for real-time applications, such as simulators or video-games. This paper presents a method for animating and rendering a prairie in real time. The geometric model for the grass relies on three different levels of detail: 3D geometry, volumetric textures (called here 2.5D representation), and 2D textures. The animation of these LODs is controlled through procedural animation primitives that implement wind effects such as slight breeze, gust of wind, whirlwind, or blast of air due to a flying object. Smooth transitions between levels of detail are computed ``on the fly'' according to camera motion, without stopping the animation. We discuss real-time performance on two platforms: an SGI O2, and an ONYX 2 with an Infinite Reality board.
