Substrate - Feedback Thread

Found an issue with transmission on a light causing artifacts on a material with subsurface scattering.

Steps to reproduce:

  1. Turn on “transmission” on a light (light set to moveable).
  2. Make a material with SSS.

The material here is quite simple. It has a color going through a Transmittance-to-MPF where the color going in has a value below 1.

When it the value is set to 1 you get fireflies in a bottle:

I’m seeing this on both Slabs with MFP (The head on screen right in the image below) as well as on a Slab with SSS Profile (the head on screen left).

I do not see this on a Surface Profile material in UE5.0. The above was tested in UE5.1.

Is this a known issue, and are there any workarounds to get back-scattering with Strata? Forward-scattering works wonderfully!