2025-02-04 Render & Cycles Meeting

Attendees

  • Brecht Van Lommel (Blender)
  • Nikita Sirgienko (Intel)
  • Patrick Mours (NVIDIA)
  • Sahar A. Kashi (AMD)
  • Sergey Sharybin (Blender)
  • Thomas Dinges (Blender)
  • Xavier Hallade
  • Weizhen Huang (Blender)

Notes

  • For Blender 4.4
  • Other
    • Nikita brought up the topic of having an option for the software image sampling
      • Previously in the related patch it seemed we can simplify our lives by not worrying about this permutation at all. The main goal of that was to simplify workload as much as possible (and not so much the removal of lines of code).
      • Since there is a request for this, and if Nikita is fine maintaining the code path we can have it as ifdef and/or CMake option. It will be easier and practical than maintaining a separate patch/branch.
    • OIDN GPU doesn’t work on Blackwell
      • There is a hardcoded check in OIDN for the SM level of 99 which is below the Blackwell
      • We can prepare a patch against upstream and tackle it as library update
      • Patrick Will check whether it is as easy as a change in that specific condition
      • Nikita brought up the topic of libraries updates and dependency between updates and adding new features.
        • If library update happens too late there is no time to utilize it for the release cycle
        • There is nothing actionable to mention on this topic. We are looking into this, and will bring some structure and amek it more predictable for everyone.
  • Brecht, Sergey, and Weizhen had a meeting to map topics Cycles team would like to focus on for the next months. Unfortunately Lukas could not attend the meeting due to schedule conflict, so it is not the final version. The topics so far are:
    • Finishing volume octree + null scattering
    • Finishing Camera shaders
    • Adaptive subdivision fixes: bringing adaptive subdivision out of Experimental
    • NanoVDB to replace “naive” dense samplers
    • Image texture cache (CPU + GPU). Mipmapped tiled images

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.

24 Likes

Nice one!

Sadly there are no rumors anymore about the Restir work from Weizhen. Is it abandoned?

3 Likes

Currently on hold. Weizhen gave a good respone in Blender chat the other day on why it’s on hold.

  • It was more complex than anticipated
  • Some of the structures neccessary for a full ReSTIR implementation do not exist in Cycles. So along with adding ReSTIR, other structures had to be added.
  • The global illumination part of ReSTIR doesn’t appear to be ready for production renderers like Cycles.
  • New papers that bring noticable improvments to various aspects of ReSTIR keep releasing, so they wanted to wait a bit more so ReSTIR can be implemented into Cycles with many of these advancements.
15 Likes

Would some of this be suitable for GSoC?
Thomas has been asking for GSoC ideas, and I believe the deadline for ideas is the 11th of Feburary?

https://developer.blender.org/docs/programs/gsoc/ideas/

Unfortunately, I don’t think so. Some of the work is already “in-flight” (there are WIP patches, etc), and other topics are much more complex than what is typically possible to tackle as part of GSoC.

I believe there are better candidates for the ideas page in the Cycles module workboard.

3 Likes

If i correctly understand, that’s HUGE!

Does It mean that Cycles Will only load in Memory the needed resolution for a specific texture based on angle/distance?
Does Tiled images mean UDIMs textures?
Does It work on big non Tiles textures as well?

Thanks in Advance!

5 Likes

Does It mean that Cycles Will only load in Memory the needed resolution for a specific texture based on angle/distance?

Technically it is based on the ray differential, so some rough bounce could make it so a lower resolution texture will be samples afterwards.

Does Tiled images mean UDIMs textures?
Does It work on big non Tiles textures as well?

No, tiled as in the pixels are stored as tiles (and not as scanlines). Some formats have native way of storing pixels like that. There would need to be some preprocessing for images to convert to such formats, similarly to maketx from OIIO.

Keep in mind, the above is more like ideas and not a concrete plan or design. We still need to work on that.

6 Likes

Is this like a prodecural lens simulation system?

[Link to Lens Sim add-on removed, moderator]

If so, that’s awesome.

1 Like

Thanks for the Clarification Sergey!
I Hope there Will be more news about It. In my opinion this Is a crucial feature for Cycles to be even more competitive with other engines!

You can see technical details in the pull request.
There is also a feedback thread.

1 Like

Does texture baking fall under the Render & Cycles module? Hopefully not off topic but the bake options only exist in the Cycles render settings.

I’m curious if nested dialectrics is still on the development outlook, perhaps for 5.0?

6 Likes

Me too! =)
Would be nice to have a clear roadmap of the further steps of the Principled V2 BSDF project listed here
(thin sheet mode, nested dielectric…)

2 Likes

I can not give more details other than we plan to finish those. And it is not necessarily Blender 5.0 topic (as in, such changes do not really need to be aligned with the major release - major release is more about allowing to break some forward compat in order to remove some maintenance burden).

P.S. I am not sure it is the greatest format to be inquiring about all sort of features in the meeting notes thread.

6 Likes

Thanks, but this is the wrong place for such kind of requests and feedback.

1 Like

Oh, ok, sorry. Deleted. If it’s useful somehow let me know where to put it.