Rhino 7 - UE 4.27 : Frustrating problems with mapping of edge softened meshes


I struggle with this topic since forever, I hope this time you’re close to solve this problem and leave it in the past.

I can’t export correctly UV unwrapped Breps with Edge Softening.
I can’t rely on extracting render meshes out of geometries and exporting them because every change means new meshes and losing the connection between UE4 and Rhino objects.

Rhino file:
RH 7 Datasmith mapping soft edges.3dm (2.1 MB)

Please take a look at mapping - on the right side it looks how it should

These are the same meshes, but the left one has wrong UV mapping

Rhino 7: Everything looks fine

Hi, looks like your post fell through the cracks. :confused:
Thanks for reporting the issue nonetheless. We’ve improved the texture mapping logic for the 5.0 version of the exporter, I just tested it with your file and the BREP mesh mapping is now exported properly!


I’m happy that you found it between the cracks. I agree that there are improvements. Unfortunately, there are still some issues that I mentioned in the first post. I really hope it can be resolved and I think you will agree with me, that even lightly softened edges drastically improve realism.
Of course, I need to work on NURBS objects and manually extracting render meshes is just to demonstrate issues.

RH7 Datasmith soft edges - 2022.3dm (2.8 MB)

1. Edge Softening of Breps still not transferring to Unreal

Please take a close look at Breps in Rhino - they have Edge softening turned ON, but after they land in Unreal (even with import option “Import Rhino meshes and UVs”) there is no Edge softening. Extracted Render Mesh obviously does have softened edges but I can’t use them because of constant Datasmiths reimports.

Direct Link
Interestingly, there is higher chance to import Edge Softened Breps by Direct Link… But sometimes there are issues when I modify Edge Softened Brep and do not change UV mapping.
It’s really confusing and there might be some coincidences, it needs some attention.

Rhino Scene and settings

2. Issues with welding?
Please take a look at Edges of Extracted Render Mesh - it has UV Box mapping.



Thanks @Czaja for your feedbacks and for taking the time to create a test file with detailed repro-steps. I was able to reproduce your issues with the edge softening and so I’ll log the bug and we will look into this!