Eecient Radiosity in Dynamic Environments

A method of determining radiosity in an environment containing moving objects, is described. This method uses the hierarchical techniques of Hanrahan et al. to obtain a static solution. Hanrahan's techniques e ciently create a hierarchical meshing of the environments geometry, and create links from element to element based on the magnitude of the form-factor between the elements. These ideas extend naturally to a dynamic environment, as only three atomic editing operations are required to update a hierarchy when an object moves: a link can be moved up or down the hierarchy, or a link can be occluded. Our algorithm exploits these simple editing processes to maintain the hierarchy, and then uses an iterative technique to solve the resulting linear system. The approach is extremely e cient, requiring little work between frames.