Scale issue on loading USD Model in Maya

Hi! We’re having troubles with usd scale in Maya.
I published an asset via Houdini (USD Model).
Bit when I try to load the Asset in Maya, the scale is off. (It’s a 100 times smaller).

I expected the scale to work properly since Maya USD Import plugin understands MeterPerUnit correctly.
Loading the asset without Ayon (Input dialog) the scale works fine. Loading with Ayon Loader the scale is off.

I already updated Ayon, Ayon Maya Plugin (0.4.10) and Maya (2026.1) without any success.
I tried to use the new Scene Units from 0.4.10 but that worked in the wrong direction?

First I set Mayas scene units to meters, then opened a new shotfile and loaded the asset. Now the asset is 1000 times smaller as it should be.

What is the “correct” way to get consistent sizing between Maya/Houdini?. Like the same way the default usd import/export works now

Just commenting that this has come up on AYON Community Discord here and here (this is you).

However, this issue has come up before on the Alliance of USD forums:

Which I feel is a very good place to ask about these kind of things - and the topics show that it’s very much a case where no real solution seems to exist?

Anyway, definitely bump those posts there if it’s important to you - because it’d reach a much wider USD audience.

In that second topic link there is mention however of a new feature in Maya USD:

For the record we did update Maya to support units and axis in Maya USD 0.31.

For Blender the import has e.g. “Apply Unit Scale Conversion” checkbox which I suppose would apply the scaling towards the Blender units. Funnily enough export doesn’t seem to have something equivalent (although it does have “Units” section which may indicate that it’d also recale to the chosen units?)

For Houdini - not sure how it comes into play, but with it’s procedural nature I’ve commonly seen just a transform or whatever in there just for the sake of taking it into houdini sims, etc.

Tagging @robert, @ralphymeijer and @jm22dogs since in the past they’ve all shown interest in this topic (e.g. in discord)

And to close off with a bit of Aaron Luk’s point:

As much as possible for now, I’d recommend that animation and game studios that have full control over their content and pipelines to use consistent stage metrics and export them explicitly, e.g., always write USD in meters with Y-up (or pick the metrics that work best for you). I see OV Metrics Assembler more as a necessity for industrial digital twins where content is coming in from many different sources and no one stakeholder has control over the stage metrics as a whole.

At least, if we do that and apply export/import conversion into the format and back at least for that unit then at least you’re doing something consistent - even if it still means the conversion is happening somewhere?

3 Likes