2022-06-21 Render & Cycles Meeting


  • Brecht Van Lommel (Blender)
  • Lukas Stockner (Blender)
  • Thomas Dinges (Blender)
  • Christophe Hery (Facebook)
  • Brian Savery (AMD)
  • Stefan Werner (Intel)
  • Xavier Hallade (Intel)
  • Sebastian Herholz (Intel)
  • Patrick Mours (NVIDIA)
  • Michael Jones (Apple)
  • Jeffrey Liu


  • The next meeting will be 3 weeks from now instead of 2 weeks, since Brecht and Lukas will be at EGSR.


  • Apple Metal: patch to distinguish between M1 chips with different number of cores will be submitted, as these are incorrectly treated as the same in benchmarks. Patch for shader optimizations was rebased but is still being worked on.
  • AMD HIP: patch was submitted for Vega support on Linux and Windows, will need some buildbot updates and can then be committed. The bug with textures for RDNA1 on Linux is being fixed, but no concrete date yet for when this lands.
  • Intel OneAPI: plan is to merge this for 3.3 still. Still some issues to solve regarding compilers, licensing, and implementation details, but there is a working implementation.
  • Principled BSDF v2: Lukas posted a design doc on the wiki, and made significant progress on the implementation, but still various things that need more work. A branch will be published soon. There was some discussion regarding compatibility with BSDF models in other software, we’ll need to make a more specific comparison of all the parameters so this becomes more clear.
  • Many lights sampling: Jeffrey got a basic implementation of the light tree working with point, spot and area lights. Next things to work on would be support for distant/background lights, which could be done by picking a light from the light tree, and then probabilistically choosing between that and distant/background lights by comparing the solid angle and energy. Another thing to check next will be to validate the light tree is working, with some simple synthetic scenes like many point lights over a plane.
  • Path Guiding: Sebastian still expects a branch to be published soon.

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.


Just to clarify, this is to be fixed on the driver side.

I have an Intel Iris Xe supported I7 chip and I installed the latest beta driver from Intel. I do not seem to be able to activate the OneApi support.

I am using https://builder.blender.org/download/experimental/blender-3.3.0-alpha+cycles_oneapi.643234a86fae-windows.amd64-release.zip

Blender 3.3.0 Alpha
        build date: 2022-06-24
        build time: 14:06:34
        build commit date: 2022-06-24
        build commit time: 12:22
        build hash: 643234a86fae
        build platform: Windows
        build type: release
        build c flags: /W3 /w34062 /w34115 /w34189 /wd4018 /wd4146 /wd4065 /wd4127 /wd4181 /wd4200 /wd4244 /wd4267 /wd4305 /wd4800 /wd4828 /wd4996 /wd4661 /wd4848 /we4013 /we4133 /we4431 /w35038 /DWIN32 /D_WINDOWS /W3 /nologo /J /Gd /MP /bigobj /Zc:inline -openmp
        build c++ flags: /W3 /w34062 /w34115 /w34189 /wd4018 /wd4146 /wd4065 /wd4127 /wd4181 /wd4200 /wd4244 /wd4267 /wd4305 /wd4800 /wd4828 /wd4996 /wd4661 /wd4848 /we4013 /we4133 /we4431 /w35038 /DWIN32 /D_WINDOWS /W3  /EHsc /nologo /J /Gd /MP /EHsc /bigobj /Zc:inline /permissive- /Zc:twoPhase- -openmp /Zc:__cplusplus
        build link flags: /MACHINE:X64  /SUBSYSTEM:CONSOLE /STACK:2097152 /ignore:4049 /ignore:4217 /ignore:4221
        build system: CMake

This is not ready yet for user testing. Those builds are only for developers to test things out, no guarantee they actually have a complete working implementation.

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We skipped today’s meeting since almost no one showed up, I guess most people are in Holiday mode. Next one will be in 2 weeks from now, on July 26.