Screen-space human skin implemented on V-Ray for 3ds Max that reduce render time 90%

[Bigguns]

The title says it all,

This guy : http://tw.linkedin.com/pub/chang-hung-liang/34/115/384

make it, I would be curious to see ant try what it can achieve!

Created a realistic and fast human skin shader featuring screen-space shading which reduces rendering time by 90% while preserving the same rendering quality. C++, 3ds Max SDK, V-Ray SDK, DirectX.

Vlado, did you were aware of this? If yes, give us some feedback, can you implement it,etc?

And if you never heard about, can you ask him to test it!? sounds really cool!
the only image we see is this one on his website: http://elianglab.appspot.com/

Jeez.. 90% faster... if it get the same quality (as he says) or even better, it's more then a deal to me!


And to add in the same post, maybe you did not saw this : http://www.battlefleet.net/Hair-s2003.pdf
http://www.battlefleet.net/BRDF-s2003.pdf

Even if it's not recent stuff, it's still ahead of what we can get.
Is it possible to make a cloth shader like this for us vlado? or something similir, a shader dedicated for doing fabrics?

And those 3d hairs are the best rendered I never seen, the shader is ultra realistic! http://forums.luxology.com/discussio....aspx?id=61780 it's not a Modo hair shader.. it's from an no officiel renderer, still not on sale..

[vlado]

Vlado, did you were aware of this? If yes, give us some feedback, can you implement it,etc?

No, I wasn't aware of the particular V-Ray shader, but I had read the GPU skin article. You could perhaps contact the author and ask him to post more info.

And to add in the same post, maybe you did not saw this : http://www.battlefleet.net/Hair-s2003.pdf http://www.battlefleet.net/BRDF-s2003.pdf
Even if it's not recent stuff, it's still ahead of what we can get.

I have seen them; for the hair results, you can actually get very good results now with V-Ray.

Is it possible to make a cloth shader like this for us vlado? or something similir, a shader dedicated for doing fabrics?

This is a scanned shader that can do only one particular kind of fabric (the one that was scanned) without artistic control of any kind. We do have the technology to scan and render many real-world materials in V-Ray and they do look amazingly realistic, however this is not available for general use yet and I don't know when it will be. On the other hand, we do plan a simplified cloth shader for general use.

And those 3d hairs are the best rendered I never seen, the shader is ultra realistic! http://forums.luxology.com/discussio....aspx?id=61780 it's not a Modo hair shader.. it's from an no officiel renderer, still not on sale..

They are indeed very realistic...

Best regards,
Vlado

[Bigguns]

Hi Vlado,

thank's for the answer.

I think it's better if you ask more info about his skin shader.. I guess he will not answer me, but you he will for sure. It may be interesting, if it work that well he says, it would be really cool... 90 % faster..

About the hair shader of Vray, it seems to be just specular on the hairs, no reflection right? Is it possible to have a gradient map that we can put in the specular slot or reflection slot that will work along the hairs depending of witch angle the light hit the hairs, it will react with different colors based on that angle of the hair? (If you don't understand I can make an image to explain you, since I don't feel it's a clean enought explanation). that way we can make hairs with different shading color in the reflection.

----This is a scanned shader that can do only one particular kind of fabric (the one that was scanned) without artistic control of any kind. We do have the technology to scan and render many real-world materials in V-Ray and they do look amazingly realistic, however this is not available for general use yet and I don't know when it will be. On the other hand, we do plan a simplified cloth shader for general use.----

Ok, wish we had this real world material! you can put online a material library of those already done plus adding that cloth shader and the simplified one, would be really awesome!

All the best,

Luc

by the way, it's the website of those who rendered the realistic hairs : http://gfar.de/hair_simulation.php

[Morbid Angel]

I didn't think that skin shader looked that good. Maybe need to see more lighting tests.

[Bigguns]

Yeah it doen't look ace, but maybe it's the model and the set up.. when the set up is bad, any shader do not look good.
We need to try it to be sure What about that Vlado ?

[Morbid Angel]

You should search for arnold's skin shader. While not without its own problems its quite a nice shader and also is fast.

[Bigguns]

I know about Arnold skin shader don't worry, ,it's nice one of course, with Vray we get almost as good ( without the greenish effect..) but it's much more slow in Vray, so if the skin shader of that guy can be 90% and has at least as good looking, it would be ace ot have it. If it's less realistic, forget it, I prefer to wait longer and get more realistic result.

[vlado]

...but it's much more slow in Vray

So what if we simply make the V-Ray shader faster?

Best regards,
Vlado

[Morbid Angel]

So what if we simply make the V-Ray shader faster?

Best regards,
Vlado

The ultimate words of power!

[Bigguns]

Yes vray skin faster would be ace, but we also need : Opacity map pleaseeeee! I'm sick to have to blend it just to make an opacity..and it has problems doing it this ways.. complicated for nothing.. and we need full control over reflection and BACK SCATTERING plz. And if you can remove the bug of greenish.. the more we put a saturated red in the sss scatter color, the more the geenish effect appears ( and of course the more you increase the radius..) Arnold don't do that.. so he has the edge on Vray here. Other then that (and the back scatter), Vray skin is very nice, one of the best.

[vlado]

Opacity map pleaseeeee! I'm sick to have to blend it just to make an opacity..

Yes, this is on the "to do" list. Out of curiosity, what do you need it for?

And if you can remove the bug of greenish.. the more we put a saturated red in the sss scatter color, the more the geenish effect appears ( and of course the more you increase the radius..)

Ah, yes. I've been looking into this more carefully recently and I found out that the "phase function" parameter can have a drastic effect on this. The default value is 0.8 and it does tend to give the material a more watery and diluted appearance. On the other hand, a value like 0.0 behave more like you would expect. I don't know how that relates to the respective values in Arnold, but my guess is that changing the phase function of its shader would produce similar results.

Best regards,
Vlado

[Bigguns]

I use alpha for the eyes, always, (like most and most peoples do too ) and I may use it on other parts of a character too(or anything else..). So I hope in the next update you will add it, will be really really handfull and a lot less pain in the a$$ to set up haha.

For the green effect, I just tried to put it at (the phase function) 0, but I founded that it gaved me no difference, I don't know how you check it in your scene.. since it's like a luminous dot, can I share you a scene to show you the effect ? Ideally it will be on a realistic head and with texture on it. that's the best way to test a skin shader and see if it look realistic or not,what to upgrade etc.

And also having a lot of control on the reflection in the mtl is very important, you may want to create a fresnel effect parametrable specifically designed for simulating the reflections of the skin,etc

[vlado]

since it's like a luminous dot, can I share you a scene to show you the effect?

Sure, the more scenes the merrier

Best regards,
Vlado

[Bigguns]

Hi vlado,

Please read all I wrote carefully to understand what I mean
Here I did 2 montage images, trying to explain better all I said earlier, hope it help And give me your email so I can send you the file so you can make test on these instead.

Also, we need control over the back scatter Vlado, plz, he's really not powerfull enought, the effect is too much subtil.. it's only not so bad when we have only one light source, and that is on the back of the head, and strong. Other wise, we have to put the back light SUPER strong to feel it a little bit.. Mentalray does the backscatter really well (the only thing the shader do well though ) so you can inspire yourself on it if you want, or better, on true life reference

Let me know if you have any question about skin shading I will be very glad to help you if I can

Regards

p.s. Just to add, you should program the shader that, when an angle is concave from let's say 120 degrees and more, the bouncing between the 2 surfaces diminish linearly till let's say 180 degrees, there it should be one bounce or something like that, you get the idea, so that way we will not have that red line of sss bouncing around the wrinkles,eyes,etc.

[vlado]

My email is vlado@chaosgroup.com, but if this is the model that you are experimenting with, I think I can get it myself online...

Also, the relation between the sss color and the scatter color is not that of interpolation; it is way more complicated physics behind them.

Since you said I should get inspired by true life, keep in mind that it has no "back scatter" control We have to implement brute force sss at some point (it would handle the thin wrinkles much better, as the sss effect can jump between surfaces), and it needs to match the fast sss shader overall, so I'm somewhat forced to stick to physically correct things. So, if you want parts of the mesh to react stronger to back light (like the ears), you have to do what happens in real-life - map the scatter radius and increase it in those areas.

Best regards,
Vlado