Pixar has released RenderMan 27.1, a maintenance update that stabilises and refines the hybrid XPU renderer introduced in version 27. The release extends MaterialX Lama functionality, aligns checkpointing with RIS behaviour, and improves stability across DCC integrations.
XPU: coating and checkpointing refined
The hybrid RenderMan XPU renderer now supports coating behaviour in the MaterialX Lama shading system. In practice, base nodes such as LamaDielectric and LamaGeneralizedSchlick correctly adjust absorption when layered with LamaLayer. This brings XPU into parity with the older RIS renderer for complex layered materials.
The update also fixes multiple shading issues. Subsurface scattering in PxrSurface and PxrDisneyBsdf now supports bump mapping when diffuse front-matter parameters are zero. Several Lama-specific bugs have been resolved, including incorrect subset computation inside combiner networks and misweighted LamaSSS importance that led to dim results. Shader memory use has been reduced by roughly 380 MB on GPU, improving efficiency on multi-layered materials.
RenderMan 27.1 also changes how XPU executes checkpoint commands. They are now triggered after a successful render rather than solely after each checkpoint, matching RIS behaviour and improving automation consistency in scripted pipelines.
Lighting and statistics
The release addresses a lighting artefact in the cylinder light’s radiance estimate function and corrects iteration-based pixel reporting in XPU statistics. The live statistics overview for both RIS and XPU now displays active pixel counts alongside iteration numbers. Data in DCC live stats panels now persists correctly after a render stops.
Blender and Houdini integration
In RenderMan for Blender, a bug that prevented AOVs from rendering correctly across multiple sessions has been fixed. RenderMan for Houdini receives several updates: the args2hda tool now generates valid disable and hide conditions, HdPrman automatically sets frame numbers in USD 25.05 and Solaris for older USD versions, and USD plugins have been moved to the dso directory for consistency.
Platform support and licensing
RenderMan 27.1 supports Windows 10+, macOS 15.x+, and glibc 2.34+ Linux. XPU is available on Windows and Linux with NVIDIA Pascal or newer GPUs. Integration plugins are provided for Blender 3.6+, Houdini 20+, Katana 7+, and Maya 2024+. Licences start at USD 845 (perpetual or floating, including 12 months of maintenance), with a non-commercial edition available for free.
