2021-07-20 Blender Rendering Meeting

Attendees

  • Brecht Van Lommel (Blender)
  • Kévin Dietrich (Blender)
  • Patrick Mours (NVIDIA)
  • Brian Savery (AMD)
  • Juan Gea Rodriguez)

Notes

Schedule

  • The meeting agreed to move to a biweekly schedule, since there is not enough to discuss every week. Most communication happens on developer.blender.org and blender.chat in between meetings, this meeting is mainly for overall coordination and decision making. So, the next meeting will be in two weeks.

Cycles

  • Cycles X: we are getting closer to feature completeness, which is required for this to go into master. This includes recent improvements the shadow catcher, render passes and various smaller features. The main remaining work is in tiled rendering and volume sampling. Of course we’ll also need some time to stabilize the implementation.
  • AMD is making good progress on their HIP implementation of Cycles-X for Windows and Linux, and they have images rendering. Cycles developers are expected to have access to drivers and a patch for testing in mid to late August. It’s unclear if this can make it into Blender 3.0, if not we aim to have experimental builds available around the time of the 3.0 release.
  • Christophe Hery from Facebook contributed a patch for anisotropy in subsurface scattering. Skin is quite anisotropic and so this can improve the realism there.
  • There is a new performance testing framework in Blender. Currently it’s used for Cycles and can produce the same kinds of graphs as found in the Cycles X announcement blog post. So other developers should now be able to reproduce these. The next step will be to run these on the buildbot.

Eevee & Viewport

  • Kévin worked on improving OpenSubdiv performance, and it’s now in a good place with multiple test files from users showing performance improvements (benchmarks). There is still work to get this feature complete.
  • Jeroen continues working on Vulkan support.

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.

  • Agenda
  • Google Meet
  • Time: Tuesday 5 to 6 PM Amsterdam Time
  • Next Meeting: August 3, 2021
19 Likes

OpenSubdiv benchmarks look game-changing!
Otherwise skin anisotropy also sounds very useful, great work guys

Was openSubDiv not using GPU before and now it is?

It will use the gpu when open subdivision is the last modifier in the stack.

2 Likes

Sorry for the question, but does “HIP” stand for something? If so, what does it stand for?

Probably the following: HIP — ROCm Documentation 1.0.0 documentation

1 Like

So the requirement for it to go into the master only include restoring features, make sense. But I still want to ask, will Path Guiding be worked on after restoring all features to Cycles X? And does Path Guiding has hope to be in the 3.0 release?

It’s so you can fire a Cycles render from the hip, like Bob Munden.

Awesome news on Cycles.

hmmm, interesting. I often put a Weighted Normals Modifier after the subsurf, in my stack, to cleanup some little artifacts in some cases, so then that will cause it to go back to CPU I guess…? :frowning:

I would have to test how much faster it is then, if that’s the case, and add an operator to my custom scripts, to maybe toggle that weighted mod(s) off/on as I work, to keep perf up then…

It would go back to the cpu, but @KevinDietrich would know more.

Indeed, it is only executed on the GPU if the modifier is the last in the stack. Although, we could in the future port a few more modifiers to the GPU. I guess weighted normals could be ported, but if the data is supposed to be made available to other render engines, or export operators (e.g. Alembic), it will have to be executed on the CPU side.

1 Like

Would it still revert to CPU if I had the Weighted Normals Mod after the subSurf but Disabled in viewport?
Or maybe that falls into that bug/design request to take into account disabled mods…

image

https://developer.blender.org/D11000

AMD is making good progress on their HIP implementation of Cycles-X for Windows and Linux, and they have images rendering. Cycles developers are expected to have access to drivers and a patch for testing in mid to late August. It’s unclear if this can make it into Blender 3.0, if not we aim to have experimental builds available around the time of the 3.0 release.

Oh that makes my day.

I hope this makes it in before 3.0 is released.

Any word on what the performance is like so far? One would hope that it is at the very least equal to Blender 2.93.

1 Like

Presumably the HIP implementation of Cycles-X will have hardware accelerated ray tracing. As such it should be faster than the current implementation of Cycles on hardware that has ray tracing hardware (currently RX 6000 (RDNA2 based) series or higher). But this is all just speculation. If the initial HIP implementation of Cycles-X doesn’t have hardware accelerated ray tracing support, then it’s very likely to get it sooner rather than later.