2022-1-18 Blender Rendering Meeting


  • Brecht Van Lommel (Blender)
  • Kévin Dietrich (Blender)
  • Thomas Dinges (Blender)
  • Patrick Mours (NVIDIA)
  • Christophe Hery (Facebook)
  • Michael Jones (Apple)
  • Juan Gea Rodriguez
  • Jeffrey (sorry, forgot to note down last name)



  • Ray offset: Brecht updated the patch with various fixes and refactoring, and added Metal RT support. Main remaining work is to get all the tests to pass, possibly by fixing the particle system to not generate identical objects and hair.
  • Metal:
    • There are still various tests failing and open bug reports. Apple internally has all the tests passing with driver fixes that should be released before the Blender 3.1 release. For some other bug reports there are workarounds. Brecht asks to update all the reports with info about the status (already fixed internally in driver, workaround planned to be committed, still being investigated, …). Then we can get a better overview of what’s still critical to fix for 3.1.
    • A bug was found in BVH2 building on Arm that caused very poor performance. With this fix, BVH2 performance is actually ~20% faster than Metal RT, so the plan is to switch to that for 3.1. Additionally this will automatically make pointclouds work and solve some issues specific to Metal RT.
  • Light groups will be postponed to 3.2.
  • MNEE is also planned for 3.2, Brecht still needs to find time to look into this.
  • Christophe mentions a bug report regarding confusing SSS radius. Two things we can do to improve things here:
    • Implement the new albedo inversion in Eevee for better compatibility with Cycles.
    • Modify the Principled BSDF to change the Subsurface parameter to not affect the radius, and instead have a separate SSS radius scale.
  • Jeffrey is interested in working on the many lights implementation in Cycles, also as part of a Google summer of code project. Updating this to the Cycles X architecture would indeed be a good project and a welcome contribution.

Eevee & Viewport

  • Kévin is working on fixing bugs in the GPU subdivision code, among them issues on AMD cards and missing normal map tangents.

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: February 1, 2022

Can ssgi appear in version 3.2?