Photon Mapping Tricks

Per H. Christensen

Abstract: This note describes six "tricks" for improved efficiency and accuracy of the photon map method. None of these tricks are particularly revolutionary or hard come up with, but it is my hope that this note can save some people the effort of reinventing them. The first trick reduces flicker in animations, while the following three tricks reduce computation times anywhere from 25% to factors of five-to-eight. The fifth trick describes how to combine irradiance estimates from several independent photon maps (for example computed in parallel on separate computers). The last trick is somewhat more experimental, but promises a speedup close to 16 in the photon tracing phase for very complex scenes.

One-line summary: Six ways to improve efficiency and accuracy of the photon map method.

Published in: Henrik Wann Jensen, Frank Suykens, and Per H. Christensen. A Practical Guide to Global Illumination using Photon Mapping. SIGGRAPH 2001 Course Note #38. ACM, August 2001. (Los Angeles, USA, August 12-17.)

Note: This course material was updated and extended in the 2002 version of this course. You may want to read that version instead.

Course web page: A Practical Guide to Global Illumination using Photon Mapping .


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