Bake SSS to vertex colors?

[Laserschwert]

Is it possible to bake the sub-surface scattering of a shader like VRaySkinMtl to the vertex colors of an object?

I've got quite a heavy array of barely moving particles (too heavy to UV Unwrap them), so I'd be fine with just a static SSS effect. Is this somehow possible?

[joconnell]

Hmm - you can save a fast sss 2 cache in the material, that might do it if you can unwrap? There's a way of loading a map into vertex colours but that'd depend on your uv's being laid out nicely.

If you use the fast sss 2 material in prepass mode for multiple scattering, set the single scatter mode to simple and then at the bottom of the options rollout, set the prepass mode to single frame (autosave) and set a filename for the prepass to write out to.

One thing of note though is that the cache is saved in world space so depending on how far your objects are moving, they're kind of sliding through the cached sss solution - you might get away with it for very small amounts but it might also cause errors.

[Laserschwert]

Yeah, I think with the SSS being fixed in world space, this might get problematic. But I didn't know about FastSSS2 being able to save out the cache at all, that's good to know, thanks!

[joconnell]

I'd say you'd give yourself a tiny bit more leeway if you used a lower, less accurate prepass rate like -1 too - widens your margin of error!