Determining Scatter Importance Sampling
Scatter Direction Regions of Interest are an integral part of an efficient scatter calculation, as they serve to direct scattered rays only towards areas of interest. In generating scattered rays, FRED evaluates the solid angle subtended by the Scatter Direction Region of Interest and handles the radiometry such that the proper amount of flux is scattered based upon the scatter model BSDF. This document provides a step-by-step process for locating and sizing Scatter Direction Regions of Interest for maximum efficiency. A script is also included for implementing the process.
Download the FRED Script: FindImpSamp.frs