Download: lcSkinShader.cgfx (save as)
Another cool shader – inspired by the Siggraph 2010 presentation 'Uncharted 2: Character Lighting and Shading' by John Hable. Its a great presentation and offers a lot of insight on how to create realistic SSS effects in shader. Unfortunately, the main topic – blurred render targets – is not possible in Maya, but the secondary techniques presented, Bent Normals and Blended Normals, are doable in Maya.
This shader takes the Blended Normals approach and adds some other elements, such as a reddish edge to the diffuse falloff, as well as uses 2 specular highlights. Also the paper describes how the Blended Normals technique results in a blue/red coloration, and the blue is not as desirable as the red, so I have implemented a very basic cyan suppression as well.
Again, a lot of attributes, but the key SSS ones are:
SSS Blended Normal Intensity – this controls the main effect of the blended normals.
SSS Edge Color – this is the color along the Diffuse Shading edge
SSS Edge Radius – this is the size of the Diffuse Shading edge coloration
SSS Edge Exponent – another tweakable parameter to adjust the reddish edge
Specular Normals Intensity – because the blended normals technique can ‘lessen’ the impact of the normal map, but overdriving the normal map intensity on the diffuse can look bad, this only overdrives the normal map on the specular highlight. Can help bring back detail.
The shadowMap and AO parts are the same as my lcHairShader.cgfx.