2022-08-23 Render & Cycles Meeting


  • Brecht Van Lommel (Blender)
  • Christophe Hery (Meta)
  • Feng Xie (Meta)
  • Brian Savery (AMD)
  • Nikita Sirgienko (Intel)
  • Patrick Mours (NVIDIA)
  • Sebastian Herholz (Intel)
  • Stefan Werner (Intel)
  • Sonny Campbell (Unity)


  • ⚓ T100569 USD Layers referencing, MaterialX, and USD Hydra rendering Addon for Blender
    • MaterialX: for the purpose of Hydra integration as proposed in that task, one way Blender shader nodes to MaterialX conversions would be enough. There are also important use cases for being able to render MaterialX in Cycles and Eevee, as well as for texture painting and baking tools. However this would require adding quite a lot of additional low level nodes to Cycles/Eevee, or use another mechanism converting to OSL/GLSL, both of which are a lot of work and should not block the initial steps in that task. Still long term it would make sense for Cycles and Eevee to support such low level nodes, and current higher level nodes could potentially become node groups.
    • Hydra: the proposed integration modifies the USD exporter to work for Hydra with support for interactive vieport updates, and integrates as a new Hydra render engine.
  • Path Guiding:
    • New OpenPGL release planned early or mid September, fixing bugs and adding macOS Arm support.
    • Sebastian plans to continue working on the implementation. Brecht asks to clarify the various TODO comments so it becomes clear which work remains.
    • Brecht plans to try some of refactoring of the kernel code to abstract away the guiding a bit better.
  • OptiX animation denoising: Patrick submitted an initial patch, but will work on a somewhat different approach that uses EXR caches on disk, that should be more compatible with future plans for resumable rendering.
  • Subsurface Random Walk: some discussion regarding “shadow terminator” like artifacts that happen, no immediate conclusion for a good solution though, it will require some experimentation.
  • Principled v2: Feng asked about artistic control over the specular rim intensity, which may not be possible with the current parameters. Perhaps additional parameters or different Fresnel modes could be added, Brecht suggested Feng/Christophe to explain parameters in their model in the task so we can more concretely discuss things. Longer term it would also make sense to support all the MaterialX closures so people can make their custom Principled BSDF, though having a feature complete one available by default is important.

Practical Info

This is a weekly video chat meeting for planning and discussion of Blender rendering development. Any contributor (developer, UI/UX designer, writer, …) working on rendering in Blender is welcome to join and add proposed items to the agenda.

For users and other interested parties, we ask to read the meeting notes instead so that the meeting can remain focused.

  • Wrong date in title :wink:
1 Like


1 Like

That would be great. Right now I’m always adding this to the Specular input in order to get more prominent rim highlights: