2022-08-25 Pipeline, Assets & I/O Meeting

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

Present: Arjan van Diest, Bastien Montagne, Brian Savery, Eskil Steenberg, Julian Eisel, Michael Kowalski, Nathan Rozendaal, Sonny Campbell, Soslan Guchmazov, Tom Cowland

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

Brian briefly presents the USD Layer/Hydra/MaterialX project.
He notes that the AMD team was mainly focussed on USD specific features (like the integration of Hydra) when working on this.
The three aspects of this work are relatively independant from each other, and should likely be split into separate projects/tasks for discussion about their integration into Blender.

Brian will discuss further with Sonny and Michael to see how his work on the ‘USD Layers’ could be integrated into the Collection I/O project.
The two approaches are very similar, but the work done in USD Layer is more part of the the later, advanced steps as laid out for Collection I/O.

Asset Browser

Due to lack of time, the OpenAssetIO topic could not be covered, it will be next meeting.

Other Topics


Eskil pitches his new binary format, HxA. The main idea is to have a simple, flexible and efficient open specified format. Another key idea behind its design is to be easy to implement from scratch.

Further, the format is also designed as some sort of meta plugin engine, with callbacks applying process on the data itself.

Here’s a video of his presentation on the format.

In relation with Blender, this could be integrated at two very different levels:

  • I/O module, could be a python add-on first.
  • The plugin part could be used e.g. as a way to extend/customize geometry nodes.

The later idea touches a lot of different topics (plug-ins, product design, several Blender modules, …). It would need a lot more design and discussions before any decision from the Blender team side. Blender being open-source, it is always possible to experiment!

Soslan has already written the I/O part as a C implementation, he will create a design task about it. We may rather want to have a python add-on as a first step.


Nathan plans to gather a group of students to rewrite the PLY I/O code in C++. He will create a design task first.

Next Meeting

The next meeting will be on Thursday 8th September, 17:00 CEST/Amsterdam time (your local time: 2022-09-08T15:00:00Z).

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


I uploaded our proposal for USD Layer importing into Blender, with Hydra rendering etc. This was discussed at SIGGRAPH at length, but it might be nice to cover this meeting too.