2023-11-30 Pipeline, Assets & I/O meeting

This is the place to take notes for on-going Pipeline, Assets & I/O meetings, before moving them to Meetings - Developer Forum . Please keep it as a clean, ready-to-use template for the next meeting.

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

Present:Bastien Montagne, Brecht Van Lommel, Charles Wardlaw, Hans Goudey, Jesse Yurkovich, Micheal Kowalski

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).



Ongoing development for Blender 4.1 targets

As a reminder, BCon1 is scheduled in three weeks.

  • Micheal: The Scene graph has a PR, still needs some work. Work on Shapekey export has also resumed. The Python import hooks may get delayed to a later release.
  • Charles: The USD colorspace PR is ongoing design discussions (differences between handling of Pixar/USD specs versus ‘rest of the world’/most DCCs, for some picture formats).
    In such cases, Blender usually takes a pragmatic approach and attempts (for importing) to support non-standard common data.
  • Geometry sets and point instancing are still in unclear state, Jesse and Brecht will check with Kevin. This needs to move forwards asap now, the merge window is getting small.
  • Status of USD subdiv schema export is unknown currently.

Collection I/O:

  • Charles made a proposal to implement a new ID type that would have registrable behaviors (for loading, drawing, editing…), and could be used as some sort of proxy for external data (e.g. USD prims or layers). However, getting such a feature fully implemented and working as expected is a huge challenge, and would require a lot of development effort.
  • Brecht made a synthetic breakdown proposal for how to move towards a better integration of USD data in Blender.

It essentially separates and simplifies the basic ‘Collection I/O’ idea, to only handle some generic exporting of collection contents to any file format that would register for it.

USD handling is then split into several steps, from relatively simple integration to complete support of a scene graph editing and ‘native’ USD data editing.

The breakdown made consensus as covering most of the desired use cases of USD in Blender. While order of priorities and implementation details remain open, there was also agreement that the first proposed USD point (to have persistent references to USD layers (and prims) in the Blender scene hierarchy) is a good starting point to move forward.

Jesse will create some design tasks based on this (at least an ‘overview’ one for USD, one for the first agreed on ‘USD references’ target, and one for the simplified generic I/O from collections).

Next Meeting

The next meeting will be on Thursday 14th December, 17:00 CET/Amsterdam time (your local time: 2023-12-14T16:00:00Z).

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