skin shader a la Alsurface pleaseeee

[Bigguns]

It seem's that Alsurface is really good at where the light hits the SSS, but when it's transitionning into shadow.. it's like there is less transmission or something.... is there possible to have control to boost one of the layer ( having a fonction on each layer ) layer in the shadow, so let's say, I found that when it's in a shadowed region, skin get too dark fast and greenish, I can boost the sss only when it would be in the shadow region ? that wya, if I want more redish scattering I can boost that option ,who would be called somehing like : shadow strenght . ? Even if it's not physically accurate I don't mind lol, all the skin shader in the world right now are not accurate no matter what.. otherwise I would not ask for this lol .

[vlado]

Yes, I have the diffusion one, will get you a build tomorrow, as I'm traveling right now.

Best regards,
Vlado

[Bigguns]

Great! Can't wait to try it to compare

[Bigguns]

Vlado, try to render with the scene I sended you, with GI on both brute force and compare with Arnold. I feel like, in Vray there is not enought multiple scattering samples occuring in the shader ( let's say it's like if the sss do just one bounce and loose energy instead of 10 let's say ) and it's why it gets that dark with one single sss layer. You need to do your test with only 1 sss layer on . As per his tutorial here : http://www.anderslanglands.com/alshaders/tut_skin1.html

There is maybe something you missed in the integration that does that.. and you were not seeing it in your test since I guess there was no GI and just one light. I think Arnold has a fonction in the render for that to allow more bouncing in the sss or something like that..

[vfxronin]

hve fun at Siggraph

[vlado]

Vlado, try to render with the scene I sended you, with GI on both brute force and compare with Arnold.

Yep, I'll try a bit later.

I feel like, in Vray there is not enought multiple scattering samples occuring in the shader

I don't really think so...

There is maybe something you missed in the integration that does that..

I doubt it, but I will double check.

and you were not seeing it in your test since I guess there was no GI and just one light.

There is GI; the ear in my IBL test gets its illumination almost entirely from GI. I did have a bug with this in the version that I posted originally, but it's fixed in the version that's available now.

I think Arnold has a fonction in the render for that to allow more bouncing in the sss or something like that..

No, not really.

Best regards,
Vlado

[Bigguns]

Opacity don't work correctly here on my side . Also, my eyes render black ( they have a transparent globe over it and it render black.. alsurface get black :/

EDIT : It work in an other scene, but not with my eyes.. I will try to see WTF is going for the opacity... or I send you that scene and you see why the alsurface get black when there is a transparent glass before it ?

[Bigguns]

Vlado, look here what they explain about the sss : https://www.yumpu.com/en/document/vi...525/p4o967v/25 Does the alsurface of vray use the same sss for it too?

[Bigguns]

Also, the green may come from lack of control of the samples like here ? : https://support.solidangle.com/display/AFMUG/Samples

[Bigguns]

Vlado, Good new's for you

I did extensive test in Arnold in Katana, and it seems to give the exact same thing as in Vray, and it's most apparent from the Directionnal mode sadly ( this mode is super for everything except that it gets darker and greenisher on shadowy angle ) ... it begs me the question. can you modify the code so that it became redish instead of greenisher in hese area's ? It's like it's using the complementary color of the sss layer, so the redisher we put it, the greenisher it get's.. and that is totally wrong... all SSS work like that and it feel so wrong.. it don't take into account the shadowed region.

The way I see it, to really work more realistic ( you can check baby skin for that, very good ref since they have a thinner skin the effect is amplified ) the lighted region and the shadowy region should be taken into account. So the front scatter and mid scatter should be more prominent into the light area and when transitionning to a darker area the deep scatter ( the red one ) should gain a lot more weight then the front.

So, to save you work, is there a way to take this shader, and just modify it so that it takes into consideration the shadow? So, telling to the shader, that when it's going into shadow, to boost the red component ( and at the same time should get rid of the green ) and diminish the green output ? Or, instead of letting the shader calculate automatically the complementary color, can we make it manual? So I would just pick a redisher color and it would be perfect skin shader, no GREEN bug I'm sure there is a way to do it! and it would be the best skin shader ever


I need to redo test in Maya, since the 2 test I did , playing with the red was not giving in more green... I don't know if the shader react differently in Maya then Katana... that's an other story. I let you know when I tested it.. or maybe it's the latest version of arnold that as a bug with the sss ? ( since the arnold in that version of Maya I tried was an older one then the one I tested in Katana,wich is the latest. )

Are you testing it in Maya-Arnold BTW ?

And can you please, post updated shader for the 3 max version with the Diffusion mode ( and is that diffusion the same thing as Quantized diffusion sss ? ) ? ( BTW , empirical is pretty cool too would like to have it )

EDIT : A friend of mine tested it in Maya and arnold and it's exactly the same he told me too so it confirm my test in Katana, so you writed it well Vlado congrat's now let's just try to make it better with the suggestion above. Let me know what you think about it please and if you get what I mean, it's maybe not so clear haha

[vlado]

Well, it's good to know

For the moment, I will just go ahead and implement the other parts of the shader that I have on my "to do" list (Beckman reflections, more SSS modes, thin translucency) and maybe the bump maps that you wanted.

Then we can focus on a way to get the greenish tints to a minimum.

For record, I actually used Arnold in Max to render my comparison images.

Best regards,
Vlado

[Bigguns]

Super Vlado Thank's for you reply

I will send you via email a scene tonight showing the how it can make a difference ( for the best ) about my wishes, I'm sure it will motivate you to do after you finish to implement all the stuff The goal is to do as good as Alsurface or.. better of course

Arnold in max? I tried it yesterday.. ligths don't work on my side, it render black.. only when I put a color in environnement it render... I don't what's wrong with it on my side.. how did you installed the alsurface in arnold in max ?

[Dave_Wortley]

Super Vlado Thank's for you reply

I will send you via email a scene tonight showing the how it can make a difference ( for the best ) about my wishes, I'm sure it will motivate you to do after you finish to implement all the stuff The goal is to do as good as Alsurface or.. better of course

Arnold in max? I tried it yesterday.. ligths don't work on my side, it render black.. only when I put a color in environnement it render... I don't what's wrong with it on my side.. how did you installed the alsurface in arnold in max ?

Did you use Max Lights or Arnold Lights? Max Lights aren't currently supported.

[Bigguns]

arnoold light of course ^^

[vlado]

Just drop the alSurface .dll in the "plugins" folder of 3ds Max and it should pick it up.

Best regards,
Vlado