2024-08-01 Pipeline, Assets & I/O Meeting

Everyone is welcome on the Google Meet linked below every other Thursday, at 17:00 CEST.

Present: Bastien Montagne, Charles Wardlaw, Dalai Felinto, Jesse Yurkovich, Micheal Kowalski, Sergey Sharybin

The meeting covers the pipeline & I/O module in a broader sense, including some topics hosted in other modules (e.g. some I/O python add-ons, or overrides and .blend file I/O from the Core module).

Links

Online Asset Projects

Dalai is working on the Online Assets project design. He had a talk with the Godot team, which has a similar project (online store etc.). So it would be nice to have a compatible system. They raised two main issues from Blender side for them:

  • UUID: Blender uses ID & blendfile names as UUID. This implies that if an ID is renamed, its references are broken.
    • No clear design or strong identified benefits currently.
  • MaterialX: Expose its export in an API, to allow other IO formats to use it (mainly Gltf).
    • Blender only supports export, with some limitations currently (targeted to Hydra renderer).
    • Extending support needs further investigations.
    • Dalai will create a place-holder task for this.

USD

Targets for Blender 4.3

Micheal and Jesse will organize themselves to work on the targets.

Regarding the issues with usdz & udim, some work has been done, what remains is likely a USD known issue.

Probably no need for USD library updates.

Michael: Point Instancing: Currently import converts point instancing to geometry nodes, but there is no clear path to do the opposite on export. Jesse wonders if working on geometry sets exports could help also handle point instancing exports. These topics also need design tasks to help investigations and discussions, Micheal will work on it.

Improved Integration of USD in Blender

See also the synthetic task.

Collection Exporter

Some minor improvements to the CollectionExport feature are planned for 4.3, like the ability to (re)name them.

Readonly Instancing

Display and very basic interaction/editing of USD data without actually importing it in Blender.

Charles created a doc for this:

Charles had a chat with some people from Apple:

  • Need for several objects (added to the doc already).

Meeting Discussions:

  • Need more work to align the original ‘object’ based approach and the new suggested ‘collection’ based approach.
  • Could also be good to consider some very similar ideas to improve Blender native linking workflow.
    • Bastien and Sergey will work on a task to write down these ideas, should help to identify the synergies with USD instancing requirements.
  • A lot of design work is needed to define how to make best use of the Outliner for these new features.
    • There is also the more remote/fuzzy idea to have a ‘scene graph’ or ‘collection graph’ using nodes to control these things.

Drawing:

  • Choice between mixing hydra rendering into Blender one or add limited support to Blender workbench is still very unclear and needs more work.
  • There are plans to improve/clarify Blender renderer API regarding which passes are provided by external render engines, which should help the mix idea to work.
  • Selection: Hydra could have some features for that too? Not a requirement for the first stages of the project anyway.
  • Need GPU devs to join this discussion.

Next Meeting

The next meeting will be on Thursday 15th August, 17:00 CEST/Amsterdam time (your local time: 2024-08-15T15:00:00Z).

The provisional meeting agenda will be linked in the #pipeline-assets-io-module channel before the meeting.

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