Efficient reuse of paths for random walk radiosity

Global illumination algorithms take into account not only the direct illumination but also the indirect one, i.e., all reflections of light. Radiosity is one global illumination model which relies on computing the amount of light transferred between the surfaces in a scene, assuming these surfaces to be ideal diffuse or Lambertian reflectors.Numerous algorithms have been proposed to find the radiosity solution of an environment. Some of them use Monte Carlo random paths. The main drawback of such techniques is their high computational cost, due to the large number of samples (paths) needed to obtain an acceptable result. The reuse of paths is a valid strategy to reduce this cost. This article analyzes in detail the techniques of reusing paths in the radiosity context for both static scenes and light animation. A noticeable gain has been obtained in our experiments.