The principle users of Radiance are researchers and educators in public and private institutions, and lighting specialists at large architectural, engineering and manufacturing firms. There are between 100 and 200 active users in the U.S. and Canada, and about half as many overseas. This community is continually growing, and as the Radiance interface and documentation improves, the growth rate is likely to increase.
For the graphics research community, we hope that Radiance will provide a basis for evaluating new physically-based rendering techniques. To this end, we provide both the software source code and a set of precomputed test cases on our ftp server. The test suite includes diffuse and specular surfaces configured in a simple rectangular space with and without obstructions. More complicated models are also provided in object libraries and complete scene descriptions.