RfB provides truly seamless access to RenderMan’s speed, power, and stability for Blender users, who can maintain a simple, Blender-centric workflow, or take advantage of the plugins’ flexibility to create an optimal, customized pipeline.

RenderMan for Blender includes two different denoisers, the RenderMan AI Denoiser from Disney Research (see Denoiser) and Nvidia’s AI Denoising solution.

Nvidia’s AI denoising is not available for macOS.

Interactive Rendering
For more information about using the Nvidia denoiser in “it”, refer to the “AI Denoise” section in Image Tool.

The RenderMan AI Denoiser currently does not work in XPU mode.

For interactive renders (viewport renders, IPR to “it”), you can turn on the denoiser by going to the viewport preferences and selecting one of the denoisers under IPR Denoiser. Optix refers to the Nvidia denoiser.

viewport_options-2.png

You should see immediate results with. the Nvidia AI denoiser, like below:

This is the result with the RenderMan AI Denoiser after two passes:

For the RenderMan AI Denoiser there are some additional controls:

Cheap First Pass: if checked, the first denoise pass will use a cheaper (slightly faster but lower quality) heuristic. This can be useful if rendering something that is converging very quickly and you want to prioritize getting a denoised result faster.

Min Samples: the minimum number of average samples per bucket before interactive denoising runs for the first time.

Interval: the time interval between denoising runs (in seconds).

Changelog RenderMan v26.3 below (summarazied)

Summary of RenderMan Updates
General
Enhanced GPU adaptive sampling for challenging scenarios (PRMAN-3004).
Fixed memory access issues causing crashes during ray-tracing acceleration builds.
Geometry
Resolved multiple motion blur issues:
Deformation motion blur (RMAN-21809, RMAN-21772, RMAN-21120).
Multisegment motion blur on points (RMAN-22573).
Consistent transform blur behavior between XPU and RIS (RMAN-22581).
Various fixes for deformation blur on curves and polymeshes.
Fixed crashes during interactive geometry edits (RMAN-22613).
Shading & Lighting
PxrMarschnerHair albedo default adjusted to 1e-5.
Improved handling of undersampled portal lights (RMAN-22606).
Fixed resolution issues with textured mesh lights (RMAN-22816).
Volumes (RIS)
Fixed crashes and clipping issues with volume aggregates (RMAN-22811, RMAN-22909).
Denoiser
Renamed –include-aovs to –debug and introduced new options:
–debug-output for custom filenames.
Tile-based denoising to reduce memory usage.
Fixed various crashes and usability issues.
Bridge Tools
RenderMan for Maya: Added Maya 2025 support and material transfer fixes.
RenderMan for Houdini – Solaris: Reduced memory usage, improved edit times, and fixed Light Linking node behavior.
RenderMan for Houdini – Classic: Reintroduced denoiser options and fixed spool panel bugs.
RenderMan for Katana: Added Katana 7.5/8.0 support, improved material import, and updated denoise macros.
RenderMan for Blender: Addressed multiple bugs, improved attribute handling, and added denoiser options.