A Pyramidal Hemisphere Subdivision Method for Monte Carlo Radiosity

Abstract

In this paper we present a new method to improve Monte Carlo radiosity by sending more rays towards selected directions. More precisely, we determine regions of the scene where the distribution of the power must be done more accurately. The number of rays sent in a direction is a function of the number of patches contained in a region, a region being a pyramid defined by the centre of the shooting patch and a spherical triangle on the surface of a hemisphere surrounding the patch. Thus, the rays shot from a patch do not have all the same power. The new method allows us not only to obtain fine details much sooner and with lower cost, but also the overall efficiency is considerably increased.