2024-04-30 Render & Cycles Meeting


  • Brecht Van Lommel (Blender)
  • Weizhen Huang (Blender)
  • Lukas Stockner (Blender)
  • Patrick Mours (NVIDIA)


  • The Ray Portal BSDF was merged for 4.2.
  • Thin Film support in Principled BSDF is planned to go into 4.2 as well. There are only a few small comments to be addressed. One thing to check is if it still matches OpenPBR, since there were recent changes in the spec.
  • ReSTIR is making progress. In the branch there are now render settings to control its behavior and various correctness issues were fixed. Current performance bottlenecks appear to be light sampling and visibility tracing. The plan is to figure out issues with fireflies due to the geometry term, and then try ReSTIR PT to handle indirect light in addition to direct light.
  • AMD is working on integrating the open source version of HIP-RT, which should add Linux support and other improvements on Windows. The long standing RDNA2 stability issue of HIP on Linux also appears to have been fixed with recent Linux kernel versions and ROCm 6.1.

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.


Hi, did you mean 4.2?

I did indeed, thanks.