I downloaded some megascans assets which render fine with H20, but lock up/crash H21. H21 is definitely not liking the hierarchy as shown by the exclamation mark in the 'Kind' column in the Scene Graph Spreadsheet. I did try fixing it with a configure primitive lop but it still crashes. The offending USD file is attached, as is an accompanying .json file (I believe it determines animated values for wind).
Has anyone encountered something like this?
H20 Render:
H21 Fail:
H21 Fail with reconfigured prims:
Edited by Hamilton Meathouse - June 30, 2026 20:18:48
robp_sidefx Can you please log this as a bug for us to investigate? Also, it looks like that USD file references a leaves USD file that isn't in the attachment.
Thanks Rob, I have submitted a bug: "Megascans usd file crashes Houdini".
Attached is the foliage file that is referenced as well, sorry for not including it in the original post (it is included in the ticket though).
This is an issue with bad USD data, which only shows up in Hydra2 (H21+). The ueJointNames data is advertised as being of type token but in the binary USD file it's actually being stored as string.
It'd be useful to know how this file was generated, in case there's likely to be a lot of such malformed files out in the wild.
In terms of making things work: - we're patching Karma to not crash on this (it'll emit a warning when it notices this) - you can use usdcat to convert the .usd -> .usda and then usdcat to convert it back from .usda -> .usd (which will properly encode the data as token)
Thanks Rob! Sorry I don't have access to the tickets themselves, but I do have an email thread with Taylor from support, I should have pinged that instead.
I've give the workaround a test and check the new build when it lands.
I have tested the following assets and they all crash. I think it's probably safe to assume all the Megaplants have the same issue, and are definitely out there in the wild: -European_Hornbeam -Goat_Willow -Japanese_Medlar -Norway_Spruce
Edited by Hamilton Meathouse - Sept. 24, 2026 15:46:09