A Ray Tracing Solution for Diffuse Interreflection

A Ray Tracing Solution for Diffuse Interreflection

TitleA Ray Tracing Solution for Diffuse Interreflection
Publication TypeJournal Article
Year of Publication1988
AuthorsGregory J Ward, Francis M Rubinstein, Robert D Clear
JournalComputer Graphics
Volume22
Call NumberLBL-22789
Abstract

An efficient ray tracing method is presented for calculating interreflections between surfaces with both diffuse and specular components. A Monte Carlo technique computes the indirect contribution sto illuminance at locations chosen by the rendering process. The indirect illuminance values are averaged over surfaces and used in place of a constant ambient term. Illuminance calculations are made only for those areas participating in the selected view, and the results are stored so that subsequent views can reuse common values. The density of the calculation is adjusted to maintain a constant accuracy, permitting less populated portions of the scene to be computed quickly. Successive reflections use proportionally fewer samples, which speeds the process and provides a natural limit to recursion. The technique can also model diffuse transmission and illumination from large area sources, such as the sky.

LBNL Report Number

LBL-22789