skin shader a la Alsurface pleaseeee

[vlado]

The hair in this paper look really smooth, can AlHair achieve a similar result?

The alHair shader uses the dual scattering approximation mentioned in the paper as an older method that they compare against. There are examples of the dual scattering approximation there, so you can see what it looks like.

The VRayHairMtl material implements actual path traced scattering and renders a lot closer to the results in that paper actually, although it needs a few improvements. Think VRayHair4

Best regards,
Vlado

[jasonhuang1115]

Think VRayHair4
Vlado

Is this coming to 3.5, 3.6 or maybe Vray 4??

[vlado]

Some friendly suggestions on the default settings for the AlSurface (referring to the nightlies for Maya):

SSS2 weight: 0
SSS3 weight:0
reflection2 strength:0
reflection1 distribution: ggx
reflection2 distribution: ggx
sampling should grey-out when "use local subdivs" is off

These are all based on the default settings of the original shader.

GGX is not the default in my version here; Beckmann is.

Best regards,
Vlado

[sharktacos]

GGX is not the default in my version here; Beckmann is.

Best regards,
Vlado

True. I was referring to this from the AlSurface docs:
"GGX matches better to empirical data, and will become the only distribution in a later version."
http://www.anderslanglands.com/alshaders/alSurface.html

[sharktacos]

Vlado could you add a GTR tail slider to the AlSurface reflection1 & reflection2? I realize it is not part of the original AlSurface (mostly because it was hard to implement I think), but since you already have it implemented for the VrayMtl I imagine it would not be difficult to add, and it is quite useful. Thanks.

[Midiaeffects]

The alHair shader uses the dual scattering approximation mentioned in the paper as an older method that they compare against. There are examples of the dual scattering approximation there, so you can see what it looks like.

The VRayHairMtl material implements actual path traced scattering and renders a lot closer to the results in that paper actually, although it needs a few improvements. Think VRayHair4

Best regards,
Vlado

I've asked because I'm curious about what is the advantage of alHair over VrayHairMtl. But if that's the case, to me looks like Vray's hair is better than alHair then! Since the latter uses an aproximation, is it faster? Now you got me curious about VrayHair4 .

Regards,
-Eugenio

[vlado]

Since the latter uses an aproximation, is it faster?

Strangely enough, no. The dual scattering approximation requires tracing several transparent hits through the hair and this is quite slow. The brute force approach of the V-Ray hair material seems to go faster, even with multiple bounces.

Best regards,
Vlado

[vlado]

Vlado could you add a GTR tail slider to the AlSurface reflection1 & reflection2? I realize it is not part of the original AlSurface (mostly because it was hard to implement I think), but since you already have it implemented for the VrayMtl I imagine it would not be difficult to add, and it is quite useful. Thanks.

Yes, we could add it easily, but then the shader won't be portable anymore Will think about it.

Best regards,
Vlado

[sharktacos]

Yes, we could add it easily, but then the shader won't be portable anymore Will think about it.

Best regards,
Vlado

Thanks, appreciate it. Could you please explain what you mean by the shader being "portable"?

[FSGFX]

i assume porting the scene to arnold...

[Bigguns]

Vlado, my hwole idea of implementing the Alsurfahe shader and Alhair, was because they were the best I've seen and I don't want Vray to lag debinh, I was Vray to be the best to go render,especially for character So, don't mind if it's not a perfect portable, what we need is it's the best sss shader out there and best hair mtl ! Make it wathever it take to be the best .. fu%k the portable thing

So make the best Vray hair Mtl you cam, if you really want to have the portable version, then do a alhair , and an upgraded vrayhairMtl . We need TRT in the vray hair mtl like I said, but you seem to come up with some new stuff also wich I encourage you to incorporate too ! We just want the best Mtl out there, that's it ^^ If you can do like in the paper you showed, we would be happy, it look's awesome ! https://benedikt-bitterli.me/pchfm/pchfm.pdf

For the Alsurface, can you add a third layer for the reflection, I got the bed reflection with 3 layers plus de new capability's of the gloss in vray 3.5 in the vraymtl, plus the control of the tail ? that would be amazing

[sharktacos]

Regarding 3 layers of reflection, I think Vlado is working on a GlossMtl which one could use to layer additional reflection on top of any material. That avoids the pandora's box of ever more reflection lobes by putting the control into the hands of the artist. I did not see it in the Maya 3.5 beta, so perhaps he can give us an update on its status?

Also let me add that I really wish the AlSurface had a checkbox to make the roughness act like glossiness. Being used to Vray it's hard in practice to wrap my head around the roughness slider, even though I know its just the inverse of glossiness. Heck, I'd be in support of making it have glossiness sliders instead of roughness. That would make it consistent with other Vray materials.

[Bigguns]

I totally agree with you on the glossiness thing , also for the MltGloss, as long as that extra gloss mtl is working in a energy preservation mode.

Regarding 3 layers of reflection, I think Vlado is working on a GlossMtl which one could use to layer additional reflection on top of any material. That avoids the pandora's box of ever more reflection lobes by putting the control into the hands of the artist. I did not see it in the Maya 3.5 beta, so perhaps he can give us an update on its status?

Also let me add that I really wish the AlSurface had a checkbox to make the roughness act like glossiness. Being used to Vray it's hard in practice to wrap my head around the roughness slider, even though I know its just the inverse of glossiness. Heck, I'd be in support of making it have glossiness sliders instead of roughness. That would make it consistent with other Vray materials.

[Bigguns]

Hi Vlado,

Can you fix the back lighting in the Vray hair ? I think it's the biggest weak point of it.. meanwhile you upgrade it ,can you make sure we have control over the back light color was well ? See my image example with the backlight, you'll see it look's wayyyyy too yellow and saturated..

I'm posting an other image of the same hair but with a different lighting, plus a brown version of the hairs, it's for my upcoming character , the vray hair shader isn't that bad.. just the default preset are quite off to looking real.. have to make some tweaks to get there. Can't to see if I can get better then that iwth the Alhair.. but if not, would be really good to upgrad the Vrayhair, with the paper you showed and the other stuff I said, I think we would have the best hair shader out there, probably better then Alhair.


Here's a ref pictur eof how the hairs react to back lighting.. you can see, it's not going nuts like in my render.

see in my render what it does...

So pretty much the same shader, in a different lighting, look's way less fake and here a brown version , BTW the hairs are still WIP ...

[sharktacos]

My experience with the VrayHair is that it does not do well, especially in the transmission with colors that have high saturation. That looks like what is happening on your render. So a quick fix is to simply lower the saturation in the transmission color.

The AlHair bases the color on melanin amount, which means the color is based on slider that produces a range of colors that are possible for human hair, rather than being whatever RGB values we artists put in, so it may fix that.

If you want to try out the melanin color thing with the VrayHair, I wrote an OSLtex for it that you can use:
http://docs.sharktacos.com/vray/osl.html#melanin