2021-06-22 Blender Rendering Meeting


  • Brecht Van Lommel (Blender)
  • William Leeson (Blender)
  • Jeroen Bakker (Blender)
  • Patrick Mours (NVIDIA)
  • Brian Savery (AMD)
  • Edoardo Dominici (Tangent)



  • Cycles X: current focus is restoring volume and multi-device rendering.
  • Brecht created a benchmarking framework based on existing code for Cycles benchmarking. First use case will be testing Cycles X performance, but intent is to use this for Blender development as a whole, including as part of the buildbot.
  • Patrick will enable OptiX native 3D curve rendering in the cycles-x branch. The shape now matches the Cycles one, and this will give significantly improved performance. It requires a new NVIDIA driver.
  • William investigates correlation issues with PMJ sampling pattern and looks into extending it into higher dimensions.
  • NVIDIA driver bug with GPU hardware scheduling on Windows is now fixed in driver version 470.x.

Eevee & Viewport

  • Kévin’s GPU OpenSubdiv support is being tested by users. The implementation was changed to work with the modifier again, since making it part of the Mesh datablock has many additional implications, and we want to do this incrementally. Implementation challenges: no PatchMap on the GPU, currently patch coordinates are computed on the CPU with yields suboptimal performance. Making all display features work (wireframes, face dots, show on cage, …) is a work in progress. Also loose edges and vertices need to be added still, since these are not supported by OpenSubdiv itself.

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.

  • Agenda
  • Google Meet
  • Time: Tuesday 5 to 6 PM Amsterdam Time
  • Next Meeting: June 29, 2021