Accurate SSS/translucency maps?
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I'm going to try and make a relatively simple grayscale map in Substance Painter to control translucency and SSS for Genesis 8 figures because I'm not really satisfied with how the usual generated DAZ ones appear to consider much of the body to be translucent enough to let light pass through. Maybe I'm mistaken, but it kinda looks weird to me to able to see light through someone's leg if there is a bright light behind it.
Does anyone happen to know if there is already such a map, or where I might find some recommendations as to which areas of the body should generally allow SSS to be visible? I'm familiar with the usual face areas: (ear lobes, cheeks, nose flesh, and lips to some extent) and a few body areas (fingers, partial hands, partial feet, toes), but I haven't been able to locate anything like a 'guide' or such in my searches so far.
Thanks in advance for any suggestions.
Comments
For game development, I use Substance Painter to bake a thickness map for SSS. I don't remember whether I have to invert it or not. But that's the idea behind subsurface scattering. Thicker areas are going to let less light shine through. I'm confused as to why the default Daz maps just seem to be greyscale versions of the diffuse map with veins in them though. Maybe I'm misunderstanding how the maps are supposed to work in Daz. Blender can also bake thickness maps, apparently. I haven't tried this yet, although I probably will shortly as I found this thread looking for the same information and need to make some SSS maps this weekend. https://www.blendernation.com/2018/09/12/baking-thickness-maps-in-blender-2-8/
I don't use translucency maps as Scattering/Transmitted Measurement Distance are enough to give skin a convincing look, but that is my personal preference. I think the default skin shader is unnecessarily complex.
Thanks for replying. I will watch that thickness map video later tonight, thanks. Yeah I also don't understand why all the SSS maps we get here are just lighter versions of the diffuse maps. I would *think* that the SSS or translucency maps would be grayscale maps showing where light would most easily pass through, which is what I planned on trying to make.
jag11, would you mind telling us your measuring distance? I did a bunch of tests and found the default settings aren't really that bad, but they're highly dependent on all the other values. It seems almost impossible to make a good SSS preset that works well with most textures.
This looks fantastic, jag11. I'd also love to know your settings, if you wouldn't mind sharing them.
Agreed. I think the closest I have seen to that are the iSouceTextures characters. I happen to like that look for skin.
I use a measurement distance of 3mm(.3 on DS property) for transmitted and scattering. For transmitted color I mostly use white, in some cases, when I need to push reds I use 236 72 72, in either cases you'll need to neutralize some reds by adjusting SSS Reflectance Tint, or the diffuse texture. I also always disable Dual Lobe Specular and Top Coat and Thin Film.
This is a comparison, MR Layla, original shader vs adjustments, same HDR and Exposure Value.
Without SSS you can end up missing things that should otherwise show through, such as veins on the backs of the hands, etc. I rebuild the SSS maps for my customized skin mashups and blend in details to make more of a "meat" texture that shines through surface/color map. This technique is also great for making tattoos look like tattoos and not stickers.
Thanks, jag11. I'll try these out tonight.
Sorry to press but is the difference between the two Layla skin adjustments just the SSS properties you mentioned or other settings too? The second looks so much more realistic than the original.
I have to say that I don't really understand SSS so I rarely touch those settings, I play around with gloss and translucency quite often but I guess I need to experiment a lot more.
Only thing different is that I replaced the default PBRSkin shader with Iray Uber Base shader to regain control over glossy settings. I must add that MR Layla's textures are great textures.
HTH
Thanks for posting your settings. I don't have that skin but I will experiment.
Thanks for sharing the settings jag11. The only issue is that with some textures at least, those settings can result in an unrealistic SSS effect when light does actually shine through a thin body part. In this example, I used the Ai texture on G8.1; left one uses your settings and right one is default. The redness is gone from the ear on the left one when a light shines behind it.
That's the tough part about all of this, I don't think there's any universal setting that works often enough because of the different ways vendors create textures. Some have translucency maps, some do it all with general values, and some adjust the skin texture to compensate. That's why I'm still looking into creating a SSS map that only indicates where skin is thin, not what color it should be.
It would all be so much easier though if DAZ would get the topology of their models right. All the ears of any generation models are way too thick, hence all the workarounds.
For those cases you can adjust the "SSS Reflectance Tint" to white or adjust "Transmitted Color".
Certainly a SSS Map can give aditional control.