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Welcome to RenderMan for Houdini 23.3!

This release of RenderMan for Houdini (RfH) 23, includes a number of new features and bug fixes that address feedback.

  • Please see the required version of Houdini for 17.5 and 18.0
  • Rendering with RenderMan will not operate on Houdini Apprentice editions. See Side FX's website for options that allow Third Party Rendering.
  • Houdini Indie is only compatible with 17.5 and higher, and you must be using at least version 17.5.210 or higher

New Features in 23.3

  • RenderMan for Houdini now supports rendering packed USD geometry within the geometry context.

  • Added new ROP options to enable illumination baking.


  • Fixed a crash when merging VDBs
  • Fixed a bug where primvars are dropped when material is applied on SOP
  • Fixed an issue preventing render updates for keyframed parameters on light shaders
  • Fixed an issue that would prevent an interactive render from stopping if an abort was issued in the "it" display
  • Fixed an issue that was causing the IPR Render shelf tool to read the ROP display rather than always starting an IPR session
  • Fixed a bug that could cause Pixel Filter mode to remain pinned to "importance"
  • Fixed a bug that would cause interactive rendering to crash when modifying materials or the timeline
  • Packed Geometry:
    • Fixed a bug where unpacked primitive geometry would not get material attribute applied
    • Fixed a bug where velocity motion blur was not applied when packed SOP was not time-dependent
    • Fixed some motion blur bugs with packed geo
    • We now export packed alembic string attributes as user attributes
  • Instancing:
    • Fixed an issue to more closely match Mantra behavior when ptinstance = off
    • Fixed a crash when instances would be created from points out of a POP or DOP node
    • Numerous other bugs when using instancing have been addressed
  • Preset Browser:
    • Fixed logging bug when using the preset browser with textures
    • A bug causing importing and exporting shader networks with PxrOSL shaders to the preset browser has been fixed
    • A bug causing importing and exporting nodes with arrays to the preset browser has been fixed
    • Address an issue where the preset browser would not import material assets with textures correctly

Miscellaneous Changes

Renamed Houdini velocity privmars called "v" to "vel"; as "v" is a reserved attribute for RenderMan geometry. Shaders in RenderMan for Houdini should refer to "vel" instead of "v".

  • "Smooth Displacement" parameter label has been changed to "Prevent Polygon Cracking" and moved to Displacement folder.
  • oslbuilder now shows up in PxrMaterialBuilder
  • Added support for ptmotionblur="deform" on Instance OBJ
  • Reorganized ROP for illumination baking options
  • The "darkfalloff" option has been added back to the adaptive sampling options
  • Added biasR, biasT, rawId, and dPcameradtime AOVs to LOPs, ROPs, and TOPs
  • Parameters with unknown widget types still being added to hda with a default UI

Known Limitations

RenderMan for Houdini

  • Can only apply materials to packed instances
  • Display edits cannot be changed from the image tool to mplay
  • Cross-frame denoising pdg support
  • Applying undo of deleted nodes or collapsing to subnet may not work as expected
  • Rewiring subnet indirect inputs
  • Rendering with Mantra lights or VOPs not possible
  • Bypassing shader nodes
  • Auto camera creation for IPR
  • RenderMan clipping planes