Contents
Welcome to RenderMan 23.6!
This release introduces improvements to RenderMan.
Please dive right into the release notes below for more detailed information on the latest version of your favorite renderer!
New Features in 23.6
There are two new optional controls for path-traced subsurface scattering - Attribute "trace" "int sssautobias" and "trace" "float sssbias". In the rare cases where the automatically computed bias for
path-traced subsurface scattering needs tweaking, one can set "sssautobias" to 0 and "sssbias" to a desired value such as 1e-6. The default values are 1 for "sssautobias" and 1e-4 for "sssbias".- Allow volumes to output their aovs via PxrTee.
The PxrPrimvar built-in names "curvature_u" and "curvature_v" for principal curvatures can now also be written "curvatureU" and "curvatureV". This is for forward compatibility with the OSL version of PxrPrimvar in RenderMan 24.
The fix for correctly combining the two shadow exclusion subsets defined by Attribute "trace" "string shadowexcludesubset" and the "string shadowExcludeSubset" parameter is now extended to dome lights as well.
Deprecate the behavior where connecting a utility pattern to a PxrSurface node forces uncached opacity computations. This has been seen to be a major performance detriment, and can be re-enabled in RenderMan 23 with Option "user" "int utilityPatternForcesOpacity" [1]
Fixes
Fixed bugs batched trace() with multiple shader groups in the hits.
Fixed a bug that could return garbage derivatives on failed texture lookups from OSL.
- Fixed a bug that could result in bad texture derivatives at UDIM boundaries.
Fixed offscreen decimation of dicing rate incorrect behavior with a custom ScreenWindow
Fixed out-of-bounds vector access when a osl spline is provided with only a single control point.
- fixed incorrect default for the number of textures in PxrTileManifold and PxrRandomTextureManifold.
Fixed rare holes in alpha channel due to missing ray hits on subdivision surfaces with intricate detail. (The holes were visible when looking at the alpha channel with gamma=0.)
Fixed a bug where derivatives where uninitalized when fetching uniform attributes and options with OSL getattribute().
Miscellaneous Changes
improvements to light selection learning
improve the behavior of denoised Marschner by changing how the albedo is calculated
- improve the degree of noise in scenes with spotlights or ies profiles