Tech Report CS-98-09

Lightning: A System for Reusing Ray Trace Data for Fast Lighting of 3D Scenes

Jennifer K. Stewart

August 1998



The most time-consuming part of lighting 3D scenes in computer graphics is the rendering and re-rendering artists have to do as they edit the lights and their parameters. Most lighting editors have some features to expedite this process, such as low resolution or fast shading render previews, but these typically fail to generate exactly the same shadows, highlights, and reflections that appear when the scene is rendered normally. We present a method for ray tracing 3D scenes where these characteristics are rendered just as accurately as with traditional ray tracing, but in up to 98% less time. By storing information from an initial, expensive, ray trace of the scene, we can re-render subsequent changes to the lights in a small fraction of the time it takes to do a regular ray trace, and far more accurately than using a low resolution or fast shading render preview.

(complete text in pdf or gzipped postscript)