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Hi,

I think I've found a bug with sss (or thin sss). While using thin sss with emitters I've noticed that it made polygons stand out as if it ignored surface smoothing.

Here is a sphere with thin sss (in an additive layer) and an emitter inside (obviously, the sphere should look smooth):



Also happens with regular sss:

Anyone else?

Please could you share your SSS and ThinSSS settings ?

I saw similar result when I pushed values to extreme (Transmittance was few mm, Coef about 2 000,...).

I can't, as I didn't save this test scene. What I've noticed is that the bug is more visible when the sss component is more dominant in the material. If a have some time I'll try to reproduce the problem.

Something like this ? I think that values are wrong or too high. Or this is an example how to do it wrong

Would be really great to see, how to use ThinSSS correctly with few examples on Maxwell Blog

[SL=18]

Here I come back with my homework done.

I picked a model from one of my scenes and illuminated it with an mxi emitter.

In this first image it has front and backface materials both with thin sss. You can already see faces without smoothing:



Then removed the backface material and made it its only material (so, no textures were used). You can still see some faces without smoothing specially at the back lit part. It is still a bit complex material with a bottom opaque layer with 2 BSDFs and a thin sss layer in additive mode on top of it. It also shows the "penumbra limit" shading problem, but that's another subject:



In order to simplify the material I then deactivated the bottom opaque layer leaving only the sss component. In this test you can see unsmoothed faces everywhere as it's color comes only from sss:



The material looks like this; nothing fancy:



This is how it looks with only an opaque layer:



I think it looks like a bug.

Nobody else has this problem? I think I saw some faceting in Eric Nixon's balloons tests (http://www.maxwellrender.com/forum/view ... 3&start=15)

I have this problem on lampshades, so +1 for fix