...

• Added a control for "thickness" for Physical Clear Coats in PxrSurface.
• Added new ground selections to the PxrEnvDaylight simulation: 
  • Legacy: Old behavior
  • Clamped Hemisphere: "Smear" horizon values on the virtual ground plane
  • Diffuse Ground: A fake infinite ground plane with diffuse color

Miscellaneous Changes

• Path Traced Sub-Surface Scattering control Zero Scatter Attenuation has been replaced by an IOR-based parameter based on total internal reflection.
• Added intensityNearDist parameter to PxrMeshLight.

• Improved live-render edit speed in cases where several LPE based AOV's were being used.

• RenderMan will now abort when attempting to recover non-incremental renders when bucket order is set to anything other than "vertical" or "horizontal".

• In OSL, gettattribute() of the "context" object can be used to access the members of the RixShadingContext scTraits structure "eyePath", "lightPath", "primaryHit", "missContext", "reyesGrid" and "shadingMode".

• Extended widget types for OSL nodes loaded at startup: 'fileInput', 'assetIdInput', 'filename' (non-standard), 'text', 'popup' and 'boolean'.
• Fixed a crash when parsing OSL shaders with int parameters using 'min' or 'max' metadata.

• Improved quality of deep output compression when a deep id channel is present.

Bug Fixes

• Fixed bug causing potential crash when using aggregate volumes.

• Fixed bug that could cause a crash when using a gprim with very many vertices and/or primvars.

• Fixed bug causing reduced thread efficiency and potential hangs when rendering many things with different grouping membership, enabled lights, or enabled lightfilters state.

• Fixed a potential crash when a hierarchical subdivision mesh specified an invalid face index in a face edit.

• Fixed bug causing a very small chance of crashing when rendering a scene containing both infinite and local lights.

• Some fixes for subsurface scattering with the PxrVCM (and PxrUPBP) integrator(s) that may have cause them to render black or with artifacts.

• Fixed potential for crash or extra memory usage when rendering a large polygon mesh having non-quad faces and __faceindex values for per-face textures.

• Fixed tile-shaped artifacts on materials with both subsurface and diffuse transmission.

• Added the correct attribute for importanceMultiplier to the PxrMeshLight

• Fix of incorrect normals of instanced NURBS patches with non-homogeneous control points. Speedup of ray tracing of some NURBS.

• In OSL, trace() and getmessage("trace") now work when hit objects are not shaded.

• Fixed a bug that could cause incorrect interpolation of primitive variables in some cases of coarsely tessellated displaced surfaces.

...