2024-08-06 Render & Cycles Meeting

Meetings
1

Attendees

  • Sergey Sharybin (Blender)
  • Weizhen Huang (Blender)
  • Patrick Mours (NVIDIA)

Notes

  • For 4.3
    • Central Cylindrical Panoramic camera model has landed (#123046)
    • OptiX SDK update to 7.4
      • Brings memory optimization for hair on OptiX (125899)
    • The OptiX OSL will be fixed by an upcoming driver update (somewhere in the future)
    • Weizhen looked into production scenes from the studio with lots of transparent bounces
      • This lead to detecting a mistake in BVH implementation, which lead to some intersections being ignored. The fix is landed (#125739)
      • Thing we can try from Cycles size is to play with the intersection array size. Maybe even somehow calculate it dynamically.
    • Weizhen looked into the crash on baking report #125863
      • It can not be reproduced reliably
      • Perhaps Sergey or Alaska can help solving it
  • Other
    • Currently under review
      • CMake CUDA PR from Patrick
        • For the priority on the timeline: nice to have for development, not essential for 4.3
      • Regression testing improvements from Alaska
        • It’s on a radar of Sergey
      • Add Metallic BSDF Node (#114958)
        • Lukas is doing reviews
        • Need to catch up a bit, to see if help from other reviewers is needed
      • Fisheye624 camera projection model (#124365)
        • Sergey reviews
        • The main point to clarify is the user interaction with the model
      • Linux Support for HIP-RT (#36108)
        • Sergey and Ray are currently revieweing.
    • Weizhen identified that fmod for float3 to be slow CPU (Apple Silicon)
      • We should test other other CPUs
      • In the past expf was slow for floats. Maybe its something similar.
      • Can also try avoiding the call when it is not needed.
    • Hashing in Perlin noise is another source of slowdown.
    • Stochastic evaluation on Perlin is faster, but looks different (using volume test scene from Andy)
    • Maybe refactor noise to reduce the number of implementations.
      • Might require changes to the way how code is vectorized.

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.

12 Likes
2

Out of curiosity, is the Metallic BSDF node slated for 4.3?

3

I think so. The majority of the work for code and review has been done already. It just wasn’t that clear state at the time when meeting happened, that’s why it wasn’t in 4.3.

1 Like