I created a shader, specifically for PBR. It's meant for complex and realistic surfaces. And is now ready for Houdini 13!
http://www.orbolt.com/asset/_danylyon::PBR_layered_material [orbolt.com]
It's written in VEX and the code is open for you to use if you buy it.
If you're interested to hear any updates subscribe to my newsletter: http://eepurl.com/G4t9r [eepurl.com]
Features:
- up to 3 individual material layers realistically mixed
- energy conserving and view dependent
- basic SSS
- refraction with basic dispersion and absorption
- translucency
- emission
- support for different uv sets
- Mari UDIM support
- individual front and back shading
- support for Cd and Alpha attribute
- bump map (normal and vector)
- built in bump noise
- built in flakes
- anisotropy (with maps)
- specular and metal specular
- adjustable specular radius and falloff
- adjustable specular sharpness at glancing angle
- adjustable roundness of the specular peak
- tint specular
- diffuse roughness and sheen
- RGB masks for individual layers
- AOVs (reflection, refraction, diffuse, emission, sss, Z, uv, velocity, normal, position, facing)
- displacement (along normal, object space or tangent space, compatible with ZBrush)
- optimization (override shadow, alpha and turn off features in reflections)
- Point based caching (experimental)
Be sure to read the help card! Click the ?