Improved Computational Methods for Ray Tracing

Abstract

This paper describes algorithmic procedures that have been implemented to reduce the computational expense of producing ray-traced images.The selection of bounding volumes is examined to reduce the computational cost of the ray-intersection test.The use of object coherence, which relies on a hierarchical description of the environment, is then presented.Finally, since the building of the rayintersection trees is such a large portion of the computation, a method using image coherence is described.This visible-surface preprocessing method, which is dependent upon the creation of an "item buffer," takes advantage of a priori image information.Examples that indicate the efficiency of these techniques for a variety of representative environments are presented.