Multiresolution Geometry Caching for Ray Tracing and Global Illumination in Complex Scenes

Per H. Christensen

Abstract: When rendering only directly visible objects, ray tracing specular reflection from large, low-curvature surfaces, and ray tracing shadows from point-like light sources, the accessed geometry is coherent and a geometry cache performs well. But in many other cases, the accessed geometry is incoherent and a standard geometry cache performs poorly. Fortunately, less geometric accuracy is necessary in the incoherent cases. We utilize the observation that coherent rays have small differentials, while incoherent rays have large differentials. We use an existing multiresolution caching scheme for textures and displacement maps, and introduce a multiresolution geometry caching scheme for tessellated surfaces. The multiresolution geometry caching scheme makes it possible to efficiently render scenes that, if fully tessellated, would use 100 times more memory than the geometry cache size.

One-line summary: A preview of our Eurographics 2003 paper.

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