SSS Method differences

[Jason Weise]

Sorry if I should be asking this elsewhere but I couldn’t find a discord channel or any other social group to ask the question in.

I am currently looking at creating some character art using Victoria 8.1 and the new PBR Skin from daz (but in Blender with this plugin) and I have noticed there are two SSS Methods in the Global settings page:

Christensen-Burely and Random Walk.

I have imported a standard Victoria 8.1 HD model and rendered a sample with both these methods but to my eye cannot see any difference.

Is there a recommended better method to use when wanting to use the new PRB Skin with Cycles.

I’m not too bothered by render times as “realism” is my aim but I cannot find any info on which SSS Methods I should be using in this case any why.

Thanks in advance and if questions should be directed somewhere other than the issues area please let me know, I am happy to comply and direct the question where required

[engetudouiti]

For BSDF option, and cycles, add on not use SSS shader, but use Volume shader to mimic iray volume absorb and scatter.

So it should be most reliable conversion for add on.

https://diffeomorphic.blogspot.com/2021/06/voluminosity-and-material-editor.html

The volume shader skin have been improved by Alessandro and Thomas. so if it work well for your purpose, you keep use Volume shader = SSS shader not be used, so both option show same effect.

Then if you prefer to use SSS shader, without volume, now it offer 2 options. I requested to avoid to generate volume shader.

The detail described here. (why I request to use random-walk then why others need to keep chiritian blur)

https://bitbucket.org/Diffeomorphic/import_daz/issues/592/commit-8376e7b-may-not-be-good

As my favor, for most of human character which use SSS,, random-walk offer more natural looking (I confrimed it with many render and I recommend serch google and see comparison videos, with some light setting,

Then if imported material SSS used really low ,(eg some vendor actually not set SSS to get clear effect = actually there seems almost no SSS effect even though they set values) usually it only mix with tanslucency shader (in daz), about the case you may not get clear difference.

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[engetudouiti]

So I may recommend

1. Try default Volume option. then spot render with set high quarity setting, (usually you may need to get final render) with Volume option untill you get clean render image.
2. try without Volume shader and compare.
3. try 2 SSS options and compare which you may prefer.

about all case, we often need to adjust SSS parameters or Volume shader node for final render as same as top coat etc, sometimes need to change each parameter hard. it is because, daz uber iray have many detail options, how effect each component, and custom curves. then add on can not auto convert for each all options. so if change way for some request, it may change another skin.

For non Volume shader option but use SSS shader, you may need more tweaking. (sometimes almost start from scratch to get reasnable skin.

I do not think add on can convert all daz iray material for real final render. I think auto conversion offer good start point. (at least they can get reasnable skin color with view port and import textures, generate base shader)

[Jason Weise]

thank you very much for the detailed response. I am going to have a play and see which one now works best for me