How do you setup SSS from Substance Painter correctly?
Hi
I did ask this on a Reddit channel dedicated to Marmoset, but I thought I'd try it here as well. I'm having problems figuring out how to setup my Subsurface Scattering correctly in Marmoset Toolbag (and Unreal). How exactly do you go about it? Whenever I export my SSS map out of SP, it looks to be just a mask. If I use the Unreal Engine 4 SSS (Packed) or Mesh Map option, that's all I get. But dropping that into the Mask slot in Marmoset doesn't do a lot. If I use a Mesh Map, and set it to the Alpha channel, this is how it looks:
It seems to think there's nothing there. If I use the packed version for Unreal, it does, but adjusting the Scatter Map still adds SSS everywhere, despite the preview material showing everywhere in black BUT where I want it to be. o_O
And then this is MT adding SSS everywhere...
I'm guessing I need a Scatter Map...? But how do you get one...? SP only gives me a mask.
Any help would be greatly appreciated. Thanks.
Replies
In Toolbag the SSS shaders can take a Scatter Map which defines the color and depth of the scatter effect, as well as a Mask that defines where the SSS effect is visible. Black values in the mask will use Lambertian shading, while white values will use SSS. So you should use the Mask texture to mask off non-translucent materials like metal, rock, etc, generally with either 0 or 1 values.
You may need to add a custom texture in Painter to author bother a scatter depth and mask texture.
You can find more info here: https://marmoset.co/posts/sss-in-toolbag-4/
For questions on exporting content out of Painter, you should try the Substance sub-forum.
Thanks for the reply. I guess I might have to ask in the Substance sub-forum. It's the Scatter Map I'm not sure about as I've never made one before.
You don't necessarily need to make a scatter map, with the color and scatter distance slider you have a decent amount of control. A scatter map would be useful if you want certain areas to scatter different colors or distances.
Hmm. So it's just the mask I need...? That alone doesn't seem to be helping much though, as I mentioned above. You said I may need to add a custom texture in Painter to get a scatter depth and mask texture...?
From the thumbnail, the mask you've created doesn't seem to make much sense. It looks like it's mostly black and dark gray values. If you've authored this to work with the SSS shader in Painter, you may need to recreate this map to work well in Toolbag or other 3D apps that have different SSS shaders. Paint and Toolbag do not use the same techniques for SSS.
The mask is a map you would want to use to mask off SSS and non-SSS materials. So if that map is mostly black or dark values, you won't see much of an SSS effect.
As to the specifics in Painter, again, you may be better suited by asking questions in the Substance sub-forum: https://polycount.com/categories/allegorithmics-substance
I posted in the Substance Painter sub-forum and I think I managed to figure it out. :)
Yes, that mask is mostly dark. The areas added that would receive SSS is really subtle. To get it working in Marmoset, I exported the texture out of SP using the Unreal Engine SSS (Packed) preset, which added the mask to the Alpha channel of the Diffuse, essentially packing them all together. When I dropped that map into the Scatter Map slot, and then adjusted the SSS slider, it only applied it to the areas in the mask. So that Diffuse/mask combo worked as my Scatter Map.
I've started another thread in the Unreal sub-forum as I'm unsure how to get it working in UE4. The method I thought worked doesn't appear to be doing anything at all. :-\