Substrate documentation says that if SSS mode is set to Diffusion but no SSS profile is assigned to a substrate slab, then the MFP and MFPScale inputs are used instead. This is apparently not true. If there is no SSS profile, no SSS happens at all, regardless of inputs. Hoping this is not intentded cause I really do NOT want to have to make a profile for every waxy/soapy/snowy object in the game just to get shadow diffusion on SSS surfaces.
We are using Blendable gbuffer. [Image Removed]
Assigning a SSS profile makes the SSS come back but also forces the model to switch to double-specular which is not desired and too costly.
That per pixel SSS mode is not supported when using the Blendable GBuffer. SSS profile must be used the same way as before then. I will see at adding a warning and update the tooltip/documentation.
When it comes to double specular, that is completely part of the SSSPRofile shading model. I guess if you do not ant to pay for that could you could add an cvar option to disable that for the platform where you want to skip it.
Ah. The problem is that i WOULD want dual spec on our human faces, but not on anything else.
The lightwrap version of SSS seems to show up but MFP becomes meaningless with a lightwrap and theres no way to make the SSS color anything but white? The docs say to avoid placing the substrate ‘shading models’ node into new materials and to instead use the Substrate BSDF Slab but I would have expected these to look the same and they def are doing something very different. [Image Removed] [Image Removed]
Lightwrap should be the same as the subsurface shading model. But this does not have screen space scattering. The controls are different, you will have to adapt the MeanFreePath because it is not the same as the Subsurface color. You cannot just replug input.
For double specular, you will have to add a dual specular bit on the profile and disable the second lobe based on that (engine change, will need update to lumen, Substrate & Deferred lighting passes at least). You can also just disable dual specular visually using currently available controls on the SSSPRofile (but the cost is the same).