2022-10-20 Pipeline, Assets & I/O Meeting

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

Present: Brian Savery, Charles Wardlaw, Julian Eisel, Matt McLin, Michael Kowalski, Sonny Campbell, Sybren Stüvel

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).


Collections for Import/Export & USD

  • Further work on USD patches by Charles:
  • Sonny:
    • Was working on unit conversions, more tricky than expected.
    • Some prototyping for collection based import/export
    • Planning to work on a doc on which parts of the USD standard are already implemented in the USD branch & what not.
    • Had discussion with Charles about custom USD schemas. There’s an idea to have application handlers for loading USD stages so custom Python code can be executed. They are looking into creating a task.
  • Matt:
    • Will have to look into the work that’s already or being done, still just getting started.
    • He’s looking into .usdz support and instancing.
    • Was also working on USD shapes so some synchronizing with Charles is needed.
  • How to best manage ongoing patch reviews?
    • Sybren doesn’t need to review every small change.
    • Maybe Hans is interested in doing some of the normal patch review work?
    • Changes that affect Blender more generally have to be discussed with core developers first of course.
    • We’ll try a patch review session half an hour before the meeting from now on.

Blender Projects

Julian was working on a first, very basic implementation of Blender Projects: D16288: Basic Blender Project Support (experimental feature)

  • This was talked about a lot in the past already, and the feature has great potential. So it was time to get this kicked off.
  • Should go into master as experimental feature soon. Then other devs can add features until it’s major enough to be enabled by default.
  • Possible features: Variables available throughout project files (like ${project-root}, ${project-name}, ${flamenco-version}, etc), environment variables, per-project asset libraries, render settings presets, etc.

Other Topics

  • Flamenco 3.1 released with a bunch of fixes and small features. 3.2 is already around the corner.

Next Meeting

The next meeting will be on Thursday 03rd November, 17:00 CET/Amsterdam time (your local time: 2022-11-03T16:00:00Z).

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


Suggestion: It would be nice to have an option (like a check box) to save the export path with the export preset in Blender. Example: If I export FBX to “D:/Export/” and check “Save export path” check box and save the preset, then, when the next time I select the preset it will automatically “open” the folder of my choice (“D:/Export/”) in the export window so that I could export there.

Hi there,

Just wondering if anyone is working specifically on alembic/USD camera importing, and also alembic/USD custom property importing?


Currently importing an alembic or usd camera with an animated focal length results in a camera with a single value (not animated) for the focal length. This means anyone working with matchmoved cameras from outside blender can’t import them for use in blender.

Custom Properties:

As far as I can tell, there is no reading of custom properties in blender’s standard alembic or usd imports - this is a very standard practice in a vfx pipeline - for example importing FX caches from houdini, would require custom shading attributes set in houdini to be readable in blender. I have managed to have some success importing custom properties on an alembic cache that came from maya, using the Nvidia ominiverse USD branch.

I have posted about this previously here:


I would be happy to test / help out in any way I can moving forward.