2025-03-04 Render & Cycles Meeting

Meetings
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Attendees

  • Brecht Van Lommel (Blender)
  • Lukas Stockner (Blender)
  • Nikita Sirgienko (Intel)
  • Michael Jones (Apple)
  • Patrick Mours (NVIDIA)
  • Sahar A. Kashi (AMD)
  • Sergey Sharybin (Blender)
  • Stefan Werner (Intel)
  • Thomas Dinges (Blender)
  • Weizhen Huang (Blender)
  • Xavier Hallade

Notes

  • For Blender 4.4
    • High priority:
      • Crash when baking textures with a modified UV map #135370
      • Problem with Shadow Catcher and World Importance Sampling #135432
      • Neither seems to be affecting the Blender 4.4 release, and they have PRs already.
    • HIP SDK public availability: it is a priority for the release
    • HIP / HIP-RT render if Blender executable has space in path:
      • Worked around for the Blender 4.4 release.
        • Only done for bvh_build_array.h.
        • oro_compiled_kernels.h could have the same issue. The issue did not manifest itself (possibly due to the data being much smaller than the bvh_build_array.h).
        • From the meeting: ORO is for low quality BVH, not used in default code-path. So need to double-check the behavior.
      • Remaining issue is OIDN on HIP, but it also did not work in such configuration in Blender 4.3.
      • Root cause: somehow hipModuleLoadData() errors out when a big buffer global buffer is passed to it.
  • Other
    • Brecht filled in the project details of texture cache and mipmaps
      • Hopefully can start working on it ASAP.
    • Brecht keeps working on adaptive subdivison and volume fixes.
    • Weizhen implements volume scattering probability guiding framework.
      • Denoising for variance estimation.
      • It can be hooked up to the current render work, but need a bit of work to hook up all the pieces together.
    • Lukas keeps working on OSL nodes for custom camera. The PR should be ready, running CI/CD as we speak.
    • Lukas plans finish all PR that are in-flight, work on FMX presentation, then come back to principled BSDF.
    • Nikita: Intel is looking into looks OIDN DLL loading issue.
    • Nikita: Node link drawing issue looking into this, could be fixed on Blender side. Nikita considers it a priority. We might be able to fix it from Blender side for 4.4, but would be good if it is fixed in driver to make older releases work.
    • HIP-RT: Fix remaining issues (especially crash) and make official.
      • Even enable by default
    • Nikita: need to find solution to communicate situation when there are 2 GPUs with different driver version requirement.

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.

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