Unreal connector plugin access violation and crash

I’m trying to get the Unreal Omniverse connector working, but I’m getting a similar access violation and crash in both the 4.25 and 4.26 versions.

The steps I’m taking are:

  • Launch UE4.25.4 with Omniverse plugin 100.2.468
  • Start a new blank project with starter content
  • Add Omniverse server localhost
  • Navigate in content browser to localhost->NVIDIA->Assets->Vegetation->Trees
  • Drag a USD file (e.g. Dogwood) into the viewport
  • I can see the actor start to be created in the world outliner, but before I can see the tree in the viewport it crashes.

Is there something I’m missing or doing wrong? I did have it working in the past with slightly different versions.

Crash log:
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000008

UE4Editor_OmniverseUSD!<lambda_b09a2d7d79506e3436ff8e22dcac9914>::operator()() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\USDConverter.cpp:8129]
UE4Editor_OmniverseUSD!FUSDExporter::ExportMaterial() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\USDConverter.cpp:8182]
UE4Editor_OmniverseUSD!FUSDExporter::ExportMeshComponent() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\USDConverter.cpp:7990]
UE4Editor_OmniverseUSD!FUSDExporter::ExportStaticMeshComponent() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\USDConverter.cpp:8095]
UE4Editor_OmniverseUSD!FUSDExporter::ExportSceneObject() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\USDConverter.cpp:7836]
UE4Editor_OmniverseUSD!AOmniverseStageActor::SaveUSD() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\OmniverseStageActor.cpp:3435]
UE4Editor_OmniverseUSD!AOmniverseStageActor::SaveChangedUE4Objects() [D:\w\22cfa8e78f62ab8a\Engine\Plugins\Editor\NVIDIA\Omniverse\Source\OmniverseUSD\Private\OmniverseStageActor.cpp:3679]
UE4Editor_OmniverseUSD!TBaseUObjectMethodDelegateInstance<0,AOmniverseStageActor,void __cdecl(void)>::ExecuteIfSafe() [D:\w\22cfa8e78f62ab8a\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:716]

We’ll get right on it, thanks for the report.

I have reproduced the crash and the next hotfix already contains a fix for this. There was a bug in the code that handles Geometry Subset materials that caused a crash in this type of prim that does NOT contain Geometry Subsets. I expect to push the hotfix out in the next few working days.


The fix for this crash (when loading Dogwood specifically) is released in hotfix 100.3, available in the Omniverse Launcher.

Further testing after release revealed another crash in other tree assets (Black_Oak for instance) due to improper attempted actor reuse on import. If you’re extensively using this tree library in Unreal Engine you’ll want to wait for the next hotfix which will contain a fix for this crash.

Excellent, thanks very much! I can confirm that Dogwood now loads properly but Black_Oak still causes a crash. Not a problem for me at this stage as I’m only testing out the features.

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