This bxdf is based on Brent Burley's extended material model, introduced in "Extending the Disney BRDF to a BSDF with Integrated Subsurface Scattering" at SIGGRAPH 2015.  It is a nice and simple physically-based model with a concise number of parameters, but at the same time it can represent a wide range of materials, including diffuse and specular reflection and transmission, clearcoat, sheen, and subsurface scattering.  All CG animations made at Walt Disney Animation Studios use this material model.

Basic

Base Color

The surface color, usually supplied by texture maps.

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The emission energy.  Non-black values represent glow.  Use this parameter with care.  Only use for low emission objects and materials.  For brighter objects, always use a PxrMeshLight.

Specular Reflection

Metallic

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Subsurface volume anisotropy (mean cosine for scattering) in path-traced subsurface scattering.  0 means isotropic scattering, values between 0 and 1 means mainly forward scattering, values between -1 and 0 means mainly backscattering.

Other parameters

Transmission Behavior

Select a transmission behavior for shadow rays: opaque or use baseColor.

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