Light Exclusions Broken With SSS

[Joelaff]

When you have SSS enabled in a VRayMaterial if you exclude the object from a light the light still affects the SSS! That's not good...

Max 2023 VRay Build 32397

Any chance of a quick fix? Thanks.

[Joelaff]

Sphere on the left is excluded from the light above it, yet it still get SSS from it. The right is not excluded from either light.

Scene attached.

[hermit.crab]

It's a known issue (internal bug-tracker id: VMAX-12526). You can workaround it by either switching the SSS's Illumination mode to Uniform or removing the excess info in post through a VRaySSS2 RE and a mask.

[Joelaff]

Thanks, Aleksandar. Is there a mathematically accurate way to remove it for just a single light using a Light Select, VRaySSS2 pass, and a mask pass?

[hermit.crab]

You could create a VRayLightSelect for SSS2 only for a particular object or shader through LPE.
1. For a particular object - add an LPE label in the V-Ray properties; add an LPE with the following code:

C<TD'obj1'>(.+L|.*[OB])

2. For a particular shader (label is m + shader name):

C<TD'mCherry'>(.+L|.*[OB])

[Joelaff]

LPE, of course! Thanks for this.