USD import with payload converting Skels to StaticMesh

Development Pipeline & Plugins
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1

When a usd file which contains a skeletal binding is “wrapped” by a referencing/payload usd interface file, the skeletal mesh is converted to a static mesh on import. Attached zip file contains a

  • `Boxy_payload.usd`: a skinned cube
  • `Boxy.usd`: an interface file that just payloads in the Boxy_payload.usd

This is reproducible in 5.6 + 5.7-preview with either legacy and interchange usd importers. We are still using the legacy importer so if a bug is confirmed that is the one we would appreciate a fix in :slight_smile:

2

Steps to Reproduce

  1. Download attached zip
  2. Import the Boxy.usd into unreal
  3. Notice that no skeletal mesh is created, but instead only a static mesh
  4. Import the Boxy_payload.usd directly
  5. Notice that the skeletal mesh is created as expected
3

Hi Luke,

The issue is due to how you structured your USD stage and you can see why in usdview. The prim Xform1 that references boxy_payload.usd is an Xform, so the root prim in boxy_payload.usd that was a SkelRoot is now an Xform. [Image Removed]You can fix this by making the Xform1 prim typeless and it will preserve the type of the root prim in the referenced stage.

def "Xform1" (
    prepend references = @./Boxy_payload.usd@
)
{
}

If you must keep Xform1 as an Xform, then you can add a typeless prim under it that does the reference instead.

Best regards,

Anousack

4

Hi Anousack

Thank you so much for the explanation, that makes sense. I should have known it was an issue with the source files.