Rhino Datasmith Fails on Second Export: Null Reference Exception

Development Architectural and Design Visualization
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1

I can successfully export a Rhino file using the Datasmith exporter plugin to Unreal, but when I try to do this a second time in the Rhino file, I get this message:

An unexpected error has occurred:
System.NullReferenceException: Object reference not set to an instance of an object.
at DatasmithRhino.ElementExporters.DatasmithRhinoActorExporter.AddActorToParent(FDatasmithFacadeActor InDatasmithActor, DatasmithActorInfo InNode, FDatasmithFacadeScene InDatasmithScene)
at DatasmithRhino.ElementExporters.IDatasmithRhinoElementExporter2.SynchronizeSynchronously() at DatasmithRhino.DatasmithRhinoSceneExporter.SynchronizeScene(DatasmithRhinoExportContext ExportContext, FDatasmithFacadeScene DatasmithScene) at DatasmithRhino.DatasmithRhinoSceneExporter.ExportScene(FDatasmithFacadeScene DatasmithScene, DatasmithRhinoExportContext ExportContext, Func2 OnSceneExportCompleted)

I’m using Rhino 8, Unreal 5.4, and the very latest Datasmith plugin version (but the issue occurred with Rhino 7 and older versions of UE5 as well).

The only way I can reexport to Unreal is to close and reopen Rhino, which massively slows down my workflow. How do I fix this?

2

I exploded all blocks in the Rhino model, which fixed this issue. However, blocks are critical to my workflow, and I really need Datasmith to handle them correctly. Is this a bug, or is this a setting somewhere I can change to fix this?