Partial, Multi-scale Precomputed Radiance Transfer

Tamás Umenhoffer, László Szirmay-Kalos, László Szécsi, Balázs Tóth, Mateu Sbert
Department of Control Engineering and Information Technology, Technical University of Budapest,
Budapest, Magyar Tudósok krt. 2, HUNGARY


This paper presents a real-time global illumination method for quasi-static scenes illuminated by arbitrary, dynamic light sources. In order to maintain real-time frame-rates, the light transport problem is decomposed to low-frequency and high-frequency parts. The part that has low-frequency characteristics both in the temporal and in the spatial domains is pre-computed. Due to the low-frequency properties this solution can be compressed by clustered PCA without significant reduction of the accuracy. The spatial high-frequency but temporal low-frequency parts are pre-computed on small-scale using a modified ambient occlusion/obscurances method. The temporally high-frequency components are obtained on the fly. This way we can combine the advantages of pre-computation aided methods and real-time rendering.