2023-02-21 Render & Cycles Meeting


  • Brecht Van Lommel (Blender)
  • Lukas Stockner (Blender)
  • Weizhen Huang (Blender)
  • Thomas Dinges (Blender)
  • Nikita Sirgienko (Intel)
  • Patrick Mours (NVIDIA)
  • Christophe Hery (Meta)
  • William Leeson
  • Michael Jones (Apple)
  • Brian Savery (AMD)


  • William Leeson is contributing work related to the cluster rendering work done at Meta, first starting with geometry optimizations that will also benefit regular rendering. A design task with more details on the bigger picture will follow as well.

  • AMD is looking at the HIP compiler bug that led to HIP binaries being temporarily disabled in 3.6. For now we can do changes in the Cycles kernel without worrying about this, and then later in the release cycle test again to see if a newer compiler fixed it, or things randomly started working.

  • Principled BSDF: no updates, patches for microfacet fresnel refactoring and improvements were reviewed and are about to be committed.

  • Light linking: there was discussion on various design approaches regarding shader vs. object controls, user interface, USD compatibility, etc. Currently it seems that collections on lights most likely work best, because other approaches like shader based linking do not work well production setups, where setting up overrides for every shader would be messy. A design problem that is also related to USD compatibility is that collections are not exactly what we want to link to, but really a specific collection instance in a stage (a path to a prim in USD). But Blender has no concept of linking to that currently.

  • Intel Embree v4 was released, with Intel GPU rendering support. Support for this in Cycles is being worked on. For CPU rendering there are some small pixel differences to Embree v3, but these are likely small enough to be ignore, and in line with similar small differences between CPU and GPU.

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.


so it’s gonna be a bit like view layer and collection ? would be best imo to at least have light control over object, adding or removing objects from a light menu, saying for example remove suzanne object from Area light.001

1 Like

The idea would be that you can create a new collection for light linking, which can then contain an arbitrary number of collections and objects in the scene.