Realistic Skin Shaders

[kepeli]

I'm trying to find out some techniques for creating realistic skin shaders. Alias have a skin shader plugin on their site but I am unsure how to get this to work with texture files also for colour, bump, specularity, etc...

Has anyone used the skin shader with texture files on their models?

Are there other ways of simulating the way light diffracts in the skin without the use of the skin shader? I have been building up the skin shader for my character with texture files only, but I don't get the falloff effect that real skin has.

Any suggestions, tips, comments are welcome.

Stuart.

[pixho]

Hi,

Basically, the skin shader manages 2 main layers. The dermis and epidermis.
The epidermis would contain all skin infos such as skin dots, imperfections of the skin, etc...
The dermis is the muscles layer, vascularity, ...
The suv_surface is the 'transparency' attribute between the epidermis and dermis. The lower the sub_surface value is, the less the dermis will be seen.
The anisotropy attr. is the 'race' attr. Pick the inversed (in the colorwheel) color to ghet the one you want.
The roughness is the specular (but inversed in luma) and the surface attr. is how the specular is 'visible' regarding human fat parts.

The lighting is really important to get a realistic skin look.
I would suggest a GI based lighting (faked or real). This works pretty well.

Another important thing: we failed in the way to foind out how we had to create our dermis and epidermis skin texture.
I've had to create a complex color calibration shading network within the skin shader to have a better control on those texture.

I know Jos hasn't yet re-compiled his skin shader for maya4. Maybe you could all send a mail to A|W so that would be done at last.

Anyway, I wish I could send some materials, but... keep dreamin'...

I think however you can create a skin shader from a standard anisotropic shader which would react with light and normal to camera....

Emmanuel

Emmanuel Campin
Lighting & shading TD
www.pixho.com

[kepeli]

Pixho,

Thanks for the reply. You mentioned the difference between the 2 layers and that the epidermis contains all the information regarding colour and imperfections. How then do I add my texture files for colour and bump to the epidermis?

Do I need to build up a layered shader using the skin shader node?

Stuart.

[pixho]

"How then do I add my texture files for colour and bump to the epidermis?"

The color information is both in the epidermis and ermis. Just remember that the dermis overall color will tint your epidermis layer. So try to avoid very saturated dermis & epidermis. They are very complementary.
But you should make some tests with just solid colors to see how the dermis interact with the epidermis.

Drag your bump node into the normalCamera attr. to get some bump.

"Do I need to build up a layered shader using the skin shader node?"

I think it's useless as the skin shader reproduces the transparency between epidermis/dermis, and the soft velvet we have.

I agree that the skin doc on A|W's site isn't that clear. Too scientific, and not for artists.

Maybe you can send emails to jos Stam (jstam@aw.sgi.com) to have more infos...

Good luck

Emmanuel

Emmanuel Campin
Lighting & shading TD
www.pixho.com