Abstract: A global illumination algorithm called Ercuts was proposed to render scenes with complex indirect illuminalion. Ercuts adopted bidirectional path tracing to initialize the scene, and generated Markov chains of the same length by ER(Energy Redistribution) sampling for each pixel. After that, a VPL(Virtual Point Light) set was developed to simulate Markov chains. Ercuts also accelerated the computation of VPLs by establishing a light tree from VPI. set and tra versing it to approximate illumination from VPLs with a strongly sublinear cost. The experimental results indicate that, compared with traditional bidirectional path tracing, Ercuts works more effectively for scenes with complex indirect illummation.

Key words: Indirect illumination, ER sampling, Virtual point lights, Light trees