We’re hitting an issue where some V-Ray proxies which have an object opacity of 0.0 are still being seen by rays cast by VRayFastSSS2. This makes sense for surfaces with opacity > 0 when simply doing a hit test for raytraced multi-scattering rather than a full shader evaluation at ray intersection. With object opacity at 0.0, most objects are completely excluded from the ray hits. The problem is that when we do get a ray hit, we get dark “shadows” in our subsurface. What’s particularly bizarre is that some V-Ray proxies function fine with object opacity set to 0.0 and some act as if they’re still > 0 even though they’re not. The original meshes from which the V-Ray proxies in question were created also function fine, so something is happening either with the creation of the VRP or with how it’s being used in 3ds Max.
An example of a simple setup with four objects, two of which are VRPs and two of which are native geometry:
Our settings for the VRayFastSSS2 shader:
Any way to work around the issue with VRPs or a way to make VRayFastSSS2 better handle hit tests on almost-transparent surfaces?
We’re using V-Ray 3 and 3ds Max 2014.
