His research is focused on realistic image synthesis, global illumination, rendering of natural phenomena, and appearance modeling. His contributions to computer graphics include the photon mapping algorithm for global illumination, and the first technique for efficiently simulating subsurface scattering in translucent materials. He is the author of "Realistic Image Synthesis using Photon Mapping," AK Peters 2001. He has rendered images that have appeared on the front covers of the SIGGRAPH proceedings (2001) and National Geographic magazine (2002), and rendered three animations that have been shown in the SIGGRAPH electronic theater (1998, 2000, 2001).