Environment Mapping for Efficient Sampling of the Diffuse Interreflection  Erik Reinhard, Lucas Tijssen and Frederik Jansen

Erik Reinhard, Lucas U. Tijssen, and Frederik W. Jansen, "Environment Mapping for Efficient Sampling of the Diffuse Interreflection", In Photorealistic Rendering Techniques, pages 410-422. Springer-Verlag, June 1994.

Environment mapping is a technique to compute specular reflections for a glossy object. Originally proposed as a cheap alternative for ray tracing, the method is well suited to be incorporated in a hybrid rendering algorithm. In this paper environment mapping is introduced to reduce the amount of computations involved in tracing sec-ondary rays. During rendering, instead of tracing the secondary rays all through the scene, values are taken from the maps for the rays that would otherwise hit distant ob-jects. This way the quality of the image is retained while providing a cheap alternative to stochastic brute force sampling methods. An additional advantage is that due to the local representation of the entire 3D scene in a map, parallelising this algorithm should result in a good speed-up and high efficiency.

Full paper (pdf)
Bibtex entry