Welcome to RenderMan 21.3!

Welcome to RenderMan 21.3 This release introduces improvements and some fixes to the previous release.

New Features

• PxrSurface's new Diffuse Exponent (when roughness is 0.0) is a power exponent that controls the diffuse falloff.
• Per lobe LPE has been added to PxrMarschnerHair, these will output results from: HairSpecularR, HairSpecularTT, HairSpecularTRT, HairSpecularGLINTS.

• New built-in primvars "curvature_u" and "curvature_v" -- the principal surface curvatures in the u and v directions. (As before, the "curvature" primvar is the mean surface curvature, ie. the average of curvature_u and curvature_v.)

Miscellaneous Changes

• Scenes that use light filter disabling may see a large drop in memory use.

• Time to first pixel in scenes with millions of lights has been greatly reduced.
• LPE system now handles complex sets of LPEs more efficiently.
• Added support for writing shadow AOV to alpha channel for holdouts
• Some error messages for RiCurves now contain more info.

Bug Fixes

• Fixed a bug that could cause sporadic crashes early in a multi-threaded render.

• Fixed missing results from baking one sided geometry.

• Fixed an error message indicating bad nesting of structs when the problem was actually just incompatible struct connections in shader graphs.

• The orientation of Nn on a sphere now matches Ngn -- there was an inconsistency for transforms with negative determinant (both for Orientation "rh" and "lh") when Option "quadric" "orientspheretotransform" is 1.

• Fixed incorrect output space for bake3d normals.
• Fixed incorrect transmission term for motion blurred volumes.

• Python RIF's now run in python3.

• Fixed a bug that could cause OSL shaders to get dropped from objects with long "identifier" attributes.

• Fixed crash in watertight dicing that could occur with some maxgridsize settings.

• Don't emit "could not acquire texture" warnings for Maya File atlas textures.
• Fixed single-scatter nested volumes writing direct lighting and emission results to LPE AOVs. The results are now correctly classified and written to the correct AOV.

• Geometric light patches no longer potentially get disabled when they happen to have a high enough tessellation rate.

• Matte objects now work correctly in Z-depth AOVs. Toggle off the "respects matte" property of the Z AOV if you wish to emulate the previous behavior.

• Fixed potential for crashes during direct-linked renderer shutdown at completion of a render that used OSL.

• Fixed potential end-of-render crash when using OSL shading nodes.
• Fixed incorrect derivatives in PxrBumpManifold2D.
• A crash that involved the aaOceanPrmanShader pattern node has been fixed.