The Ray Tree

When ray tracing a scene, reflected or transmitted rays may strike other reflective or transparent objects. Further reflected or transmitted rays will be spawned, and so on. Taken together, such a family of rays is termed the ray tree. Care must be taken to control the depth of this tree: If it is allowed to grow too deeply, one may spend a great deal of time computing rays that contribute little to the final picture; if it is not allowed to grow far enough, this premature tree pruning may be evident in the image.

Rayshade provides two complementary methods for controlling the depth of the ray tree. One method sets an absolute maximum for the tree. The other allows one to adaptively prune a tree as it grows so that ``unimportant'' rays are not spawned.

maxdepth level
Do not spawn rays deeper than those at the given level.

cutoff threshold
Do not spawn rays whose contribution to the final color of the eye ray is less than threshold for each color channel. Threshold may be given as a single floating-point value, or as a red-green-blue triple.