A New Hemisphere Subdivision Technique For Computing Radiosity
Vincent Jolivet, Dimitri Plemenos · 1998
The hemisphere subdivision technique is an importancedriven technique using a triangular adaptive subdivision of a hemisphere in order to guide the rays shot from a patch [17]. The purpose of this technique is to take advantage of the knowledge of an environment in order to optimise the space distribution of rays shot in radiosity algorithms. In this paper, we present a new approach of the hemisphere subdivision technique, allowing both reduction of time and memory costs of the technique and improved results. Like the initial hemisphere subdivision technique, this approach, uses a heuristic function which estimates visibility complexity in a given direction from a patch. The knowledge of this complexity is used as a guide for subdividing a hemisphere associated with the patch, in a number of equilateral spherical triangles of various sizes. Then, during a number of steps chosen by the user, new rays are sent in specific directions derived from the hemisphere subdivision.