16132f8c79
`CLOSURE_WEIGHT_CUTOFF` avoids allocating a closure when its weight is too small. It makes sense for surface closures, but for volume closures the contribution also depends on the object size/ray length, such a cutoff seems random and is causing problem in atmospheric scatterings. Therefore remove the cutoff for volume, just make sure the weight is positive. Pull Request: https://projects.blender.org/blender/blender/pulls/131696