I’m hoping I can soon use Cycles to make animations. Since GPU rendering doesn’t work on AMD cards and CPU is so slow, I need to keep ray bounces and samples to an absolute minimum… and of course I don’t want to get noise either. I saw many tutorials on how to reduce noise with minimal samples, and disabling bounces entirely is a compromise that helps too. But I noticed something else last night, which wasn’t covered much in those tutorials: The type and positioning of lights heavily affects noise as well. I’m looking to understand this better.
From what I noticed, fewer light sources in the same area reduce noise. This makes sense, since I assume that the more lights you have the more places each ray can jump to. I also noticed that object lights (point, spot, sun, etc) cause less noise than mesh lights. Some artists stated otherwise, but in some cases a single sun light results in absolutely no noise with just 1 sample.
Are there any in-depth tutorials on how the placement of lights must be done to reduce noise to the maximum? What can cause a light to make everything more grainy? How should lights be placed in complex scenes (in holes, between walls, etc) so noise is avoided? Also, when should “Multiple Importance Sample” be used?