...

• Shading
  
  • PxrUnified integrator is currently experimental as it does not yet support all the standard rendering features.
  • PxrSurface back diffuse color is not output to the albedo color AOV
  • <primstr:nameofvalue> substitution of data from a constant primvar or user attribute on an object for dynamic filename substitution is not yet working for the gettextureinfo() OSL call.
  • Using the ' . ' character in the handle for an OSL shader could cause unpredictable results during re-rendering.
• Performance:
  • OSL startup.  We have upgraded to OSL 1.10 for both RIS and XPU in RenderMan 24.  We have found that this upgrade (and its dependencies) have slowed down time to start up.

  • Volume integration with patterns.  Because of the switch from C++ to OSL patterns and the sensitivity of volume integration to pattern execution, there are performance regressions with volumes in RenderMan 24 compared to RenderMan 23 that remain to be addressed. There are also memory increases that remain to be addressed.  This is most noticeable when the volume density is connected to a pattern (e.g. PxrPrimVar); the performance regression can be avoided by avoiding a pattern connection if possible.

• Interactive instrumentation/statistics:
  • Bridge product (Maya, Katana, Houdini, Blender) initial integrations are available, but are turned off by default.  Artists can turn on the statistics through the buttons in the UI.
  • Web browser integration is still to come and is now likely to arrive in a future version of RenderMan.
• General rendering
  • Load on demand procedurals are not supported anymore, all procedurals are now loaded immediately
  • We do not read point data from OpenVDB files
  • Per-Instance baking is not supported, only the reference instance.
  • 3d baking: no direct bake-to-ptex support.
  • PxrBakePointCloud cannot directly render ptex.
  • Sample/Display filter plug-ins do not have access to lighting services for light dependent effects, e.g. lens flare.
  • Adding new mesh light on existing geometry during IPR results in double geometry.
  • Motion blurred polygons do not motion blur normals when deformed. Use Subdivision meshes instead.
  • When attempting to access an array primvar, you must first check the size of the array primvar and allocate the appropriate space. Not doing so may lead to a crash.
  • Points and curves cannot be used as geometric lights.
  • Analytical lights placed inside volumes may yield artifacts when made visible to the camera. As a work around, the light camera visibility should be turned off, and a geometry with a similar shape should be used (visible to camera, invisible to transmission and indirect rays), with the proper emissive bxdf.
  • Path Guiding in PxrUnified causes a crash
• Bridge Products:
  • RfH: Soloing Lama nodes in complex shading networks can give incorrect result

...