Résumé: Procedural techniques for modeling complex surfaces (fractals, implicit surfaces, etc.) and geometric textures (texel maps, displacement maps, etc.) cannot be integrated efficiently into most current radiosity algorithms, since these techniques impose a geometry limited to patches (elementary surfaces). The usual way for including the above-mentioned complex features consists of applying a high rate sampling into small triangles. Often, the resulting enormous geometric complexity (millions of triangles) overloads the memory and computation capacity. In this paper, a radiosity approach for integrating efficiently all kinds of complex surfaces and geometric textures is presented. It is based on the use of virtual surfaces, solid irradiance and ray tracing techniques. The virtual surfaces simplify the overall geometry. They are used to calculate energy exchanges in the scene during the "rst pass of the radiosity simulation. The solid irradiance is used to estimate the incoming radiance on any point of the complex surface or geometric texture in order to compute the illumination of this point during the final rendering process (second pass). Finally, ray tracing techniques, adapted to the ` direct a (e.g. without intermediate geometry) rendering of implicit, fractal or displacement mapped surfaces, allow us to avoid the high rate sampling into small triangles.

Langue: Anglais