@zefreestijl , Hi
Here is the sample part screen dump from Rhino6 and I have saved the part “Save Small” to make sure no mesh was generated in Rhino. There is no bad objects with the part either.
Here is the Dataprep screen after “Import” . Noted the untrim large circle formed around the original part.
Here is the screen dump by import 3dm directly from Datasmith without Dataprep with “Import Rhino Meshes and UVs” option
I used Rhino6 and UE4.26 in these experiments.
Lastly, if I save the rhino file with meshes and create a new Dataprep Asset object. I can (sometimes) import the part as mesh. The untrim circle disappears. However, I cannot reliably make the Dataprep to import the generated mesh by Rhino6.