An Irradiance Atlas for Global Illumination in Complex Production Scenes

We introduce a tiled 3D MIP map representation of global illumination data. The representation is an adaptive, sparse octree with a "brick" at each octree node; each brick consists of 8 3 voxels with sparse irradiance values. The representation is designed to enable efficient caching. Combined with photon tracing and recent advances in distribution ray tracing of very complex scenes, the result is a method for efficient and flexible computation of global illumination in very complex scenes. The method can handle scenes with many more textures, geometry, and photons than could fit in memory. We show an example of a CG movie scene that has been retrofitted with global illumination shading using our method.