BSSRDF importance sampling

Abstract

Light propagation within translucent materials can be described by a BSSRDF [Jensen et al. 2001]. The main difficulty in integrating this effect lies in the generation of well-distributed samples on the surface within the support of the rapidly decaying BSSRDF profile. Jensen suggested that these points could be importance sampled but did not provide implementation details. More recently, Walter et al. [2012] and Christensen et al. [2012] proposed other sampling methods which can still suffer from excessive variance.