Found the main problem with ElephantWithMonochord

[spiffmon]

@hybridherbst , @meshula pointed me at this great writeup of an asset! I confirmed that the monochord does not playback in usdview, but it is not a two-skeleton problem. Rather the problem is that the "Monochord_Vibrator" Mesh is parented under the "Monochord_Base" Mesh, and USD forbids the parenting of Gprims under other Gprims.. in this case it causes Hydra to not apply the skeletal deformation properly. usdchecker does flag this as an error.

I used usdedit to make the Vibrator mesh a sibling of the Base Mesh (after unzipping the package), which was straightforward as the Base has no transformation on it. With this single fix the animation plays back as intended for me in usdview. THough, usdchecker still generates a bunch of errors and warnings. Most of them can be resolved by running usdfixbrokenpixarschemas, though not the shader-under-shader issue, which is currently not as cataclysmic as gprim-under-gprim.

The shading looks like it came from Maya, before it was fixed about a year ago, though I didn't think the Maya usdExport would ever produce a Mesh-under-Mesh...

[hybridherbst]

Hey @spiffmon, thanks for looking into it!

The asset is actually exported using com.unity.formats.usd(cc @jcowles). Interesting that it plays fine in other viewers.

[jcowles]

Thanks for the CC, I've reported this internally as well.