Rendering Techniques '95 (Proceedings of the 6th Eurographics Workshop on Rendering), p.11-20, 1995.
In this paper we present a 5D tree structure to cache illumination information gained during Monte Carlo ray tracing. The structure is elegant and simple to use. It is adaptive and makes abstraction of the complexity of the input scene automatically. We then show how the information in this structure can be used to reduce the variance of the Monte Carlo process. Unlike earlier approaches the techniques presented here do not introduce a bias in the results.
