This gives you "Multiple Importance", "Distance" and "Equiangular" choices. What multiple importance sampling does is make things more robust to certain types of noise at the cost of a bit more noise in cases where the individual strategies are always better. So if you've got a pretty dense volume that's lit from far away then distance sampling is usually more efficient. If you've got a light inside or near the volume then equiangular sampling is better. If you have a combination of both, then the multiple importance sampling will be better.
6.8 KiB
6.8 KiB