2020-10-06 Blender Rendering Meeting


  • Brecht Van Lommel (Blender)
  • Jeroen Bakker (Blender)
  • Lukas Stockner
  • Patrick Mours (NVIDIA)


Meeting Organization

Proposal by Brecht agreed on by attendees

  • Make link to meeting public, but emphasize that this is a meeting for contributors only, for users we refer to the meeting notes.
  • Do not bring up confidential information in the meeting - leave that information for other channels. This is a meeting about Blender development which is all public.
  • Meeting will not be recorded or live streamed at this moment

Status of Ongoing Projects

  • Eevee Renderpasses
  • Blender Vulkan Support: https://developer.blender.org/T68990
    • Ongoing development by Clément, nothing to discuss in the meeting until heis back from holidays.
  • Cycles NanoVDB: Blender Archive - developer.blender.org
    • Patrick looks at optimizations and improvements still.
    • Brecht suggest looking into half-float to halve memory usage of the leaf nodes.
    • When master opens for 2.92, Brecht will ask platform maintainers to update the OpenVDB libs.
    • Upgrading to the nanovdb branch should be fine regarding the VFX reference platform, since the OpenVDB library has good backwards API/ABI compatibility.
  • Eevee NanoVDB?
    • No current GLSL implementation for NanoVDB, so would need to be implemented first.
  • Cycles CUDA 11 upgrade: Blender Archive - developer.blender.org
  • Cycles multithreaded object export: Blender Archive - developer.blender.org
    • Being reviewed by Brecht and Sergey for 2.92
  • Cycles CPU + GPU
    • Lukas works on tile stealing and GPUs rendering multiple (smaller) tiles at the same time.
    • Main challenge remaining is making it work well with the OpenCL split kernel, for CUDA.
  • Principled BSDF improvements
    • Lukas works on replacing the GGX multiscattering one with a faster approximation. Brecht suggest to look at Eevee implementation in case the same approach can work.
    • Lukas works on improved metallic fresnel in the principled BSDF. Brecht suggest to look at how the parameters are handled in Standard Surface, to share the specular color between dielectric and metallic and smoothly blend.
  • Network rendering
    • Lukas planning to contribute a (simplified) patch for this
    • This feature would remain disabled for official releases until it has had more testing, but it at least avoids code divergence.
    • Currently no support for OptiX and Embree due to BVH building needing access to Cycles data structures.
    • Patch adds dependency on protocol buffers, need to look into
  • OptiX SDK:
    • We will need to upgrade at some point to take advantage of newer features (curves, …).
    • Wait for now since it bumps the required NVIDIA driver versions, Patrick will notify brecht when it’s needed for new OptiX features.

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.