ZBrushCentral

Tutorial- Faking SSS Without Shaders

People have achieved some great results with tri and quadshaders to achieve a fleshy sub-surface scattering effect. One drawback I have found is you generally have to work blind with the model getting part of its colour from the shader and part from the texture. It can get a little tricky to control with a render required to see the true appearance.

This shows a quick way I have used in the past to get more of a fleshy look when using just the basic shader. It’s maybe not as realistic as other methods but it is easier to use. It allows you to texture your model in the workview knowing it will more closely resemble the final render.

[![pault_sss_demo_comp.jpg|916x412](upload://sGv1fAONk9bgOzH9CDWSME8dTuR.jpeg)] 1. Render out a base pass or passes for your scene with it's main lights.
  1. Turn off all lights(including ambient) and turn the materials specularity down to zero. Add a centrally positioned radial light with shadows turned off. This will illuminate the surfaces of the model turning away from the camera. Render this as another pass. Technically this is just a backlight effect but it can be used to make a model look more ‘alive’.

  2. In photoshop or other compositing app, put the radial light pass over the base and set it to linear dodge. Adjust opacity of the radial pass to get the desired look. You can also try adjusting the hue and the levels of the radial pass. The colours in the radial pass make the colours of the base richer when composited this way. This gives a nicer effect than if the radial pass was rendered in one go with all the other lights. It also allows you to easily control the look via compositing rather than performing endless test renders.

    Any questions…post away.:slight_smile:

    Hope it helps,

    Paul

Thanks 3DP. This is very useful advice.

Good advice, and very clear illustrated.

Thanks

Ralf Stumpf

Looks interesting, I’ll have to try it. Thanks! :+1:

Very interesting technique…I’ll try it out soon :slight_smile:

Yong
http://www.3dtavern.com

oops I missed this one…cool idea…and you gave me some other ideas to add to my way too many ideas of trying to stay in zbrush for render passes and effectively using layers and baking. I think I thank you for this:rolleyes: but we will see someday!:smiley:

Thanks for sharing your tips…I think actually this adds a piece I was missing to my puzzle.

looks good. Just tried it… but my radial light setup really doesn’t provide as high contrast back light look as you seem to get. If i increase the intensity it just washes out the front as well.

Could you post your light setup?

Cheers
El-d

You need to play with the curve in the light panel to get the falloff.

couldn’t see the wood for the trees
cheers 3dp.
El-d

Ouch, that’s the sound of me kicking myself, so simple & a great result…

Thanks 3DP…:+1:

This technique is actually very useful, but I don’t think that the look you are creating is actually related to subsurface scattering. The SSS material in Max has an option for reflectivity, and if you read Neil Blevin’s site (he’s something of a guru for 3DS Max materials, formerly with Blur Studios, now with Pixar) he discusses how many non-metallic surfaces have a Fresnel type reflection, they become more reflective the greater the angle at which they are seen.

I think this technique makes your dinos look more realistic because you are faking something of a fresnel reflection, which could help the material resemble organic material, anything wet, or plastic.

Neil’s website:
http://www.neilblevins.com/cg_education/metal_and_refs/metal_and_refs.htm

Speaking non-tecnically, this is bloody excellent!

I’ve been trying to do something like this for a while, but haven’t quite gotten as good a result as this. Thanks.