[Branch "dev"] Crash when loading usd-wg vechicle "geo" models

[tellypresence]

(update: these models load OK on rendermesh-refactor branch, should be able to close this once merged back to dev)

Steps to reproduce:

• On dev branch, attempt to load model 4wdGeo.usd

With verbose logging enabled, will see the following logged; after line renderMaterialId = -1 the application crashes

tinyusdz_repo/src/tydra/scene-access.cc:BuildXformNodeFromStageRec:2102 Not xformable
tinyusdz_repo/src/tydra/render-data.cc:MeshVisitor:2392 Material: </_wd>
tinyusdz_repo/src/stage.cc:GetPrimAtPath:97 GetPrimAtPath : /_wd(input path: </_wd>)
tinyusdz_repo/src/stage.cc:GetPrimAtPath:117 clear cache.
tinyusdz_repo/src/tydra/shader-network.cc:operator():275 GPrim has no materialBinding.
tinyusdz_repo/src/tydra/shader-network.cc:FindBoundMaterial:327 search parent: /_wd
tinyusdz_repo/src/stage.cc:GetPrimAtPath:97 GetPrimAtPath : /_wd(input path: </_wd>)
tinyusdz_repo/src/stage.cc:GetPrimAtPath:126 Found cache.
tinyusdz_repo/src/tydra/shader-network.cc:operator():275 GPrim has no materialBinding.
tinyusdz_repo/src/tydra/render-data.cc:ConvertMesh:1235 num_fvs = 1836
tinyusdz_repo/src/tydra/render-data.cc:MeshVisitor:2477 renderMaterialId = -1

Note: these models are also observed to reliably crash in similar fashion:

• ambulanceGeo.usd
• formulaGeo.usda

Please check results and see if the failure can be dealt with gracefully, thank you

[syoyo]

You should describe mode details on reproducing procedure and error.

At least tusdcat 4wdGeo.usd works well and does not crash.

[tellypresence]

NOTE: these models load OK on rendermesh-refactor branch, must have fixed something

(ignore the broken faces, that's a known separate issue)

Model	Screenshots
	Solid	Wireframe
4wdGeo.usd
ambulanceGeo.usd
sedanGeo.usd

[syoyo]

tusdcat 4wdGeo.usd also works on dev branch.