Same geometry, but different analysis meshes?

My rhino 7 SR30 constantly crashes when I try to export to twinmotion.
I managed to narrow the issue down to a few very specific surfaces when joined into a polysurface.

When I investigated it more, I found that the analysis mesh looks very weird.
It is divided into pieces. Which I suspect is the reason why during export to twinmotion, Rhino instantly crashes.

Above image is the extracted analysis mesh of the faulty geometry.

Interestingly enough, if I select the original surfaces and save as another 3dm file with the “save geometry only” option ticked, then that file will export just fine.
I checked its analysis mesh and it looks a lot cleaner even though, I didn’t change anything.

Can anyone explain how to correct the surfaces or why this is even happening?

3dm file is attached.
tm_crash.3dm (214.5 KB)

Hello- I see there is something funny with meshing these objects- were they created in Rhino? Do you have any input curves for these? Were they scaled from larger or smaller originals?


I do not remember fully, but chance is high that I created it in rhino.
Seeing the rest of the geometry were also created in rhino (geometries which I deleted to isolate the issue)

I do not have any input curves, but if memory serves me, I created a rectangular box first and then used edge fillet.
Orignal box looks more like this:

Hello- thanks, I cannot repeat it here so far - your surface insists on making an ugly mesh so far no matter what I do, a new fillet or revolve seems fine. I’ll run it by the developers.


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Thank you, @pascal .

I look forward to your reply.
Very intrigued to find out what the cause could be.

This looks to be related to box mapping. Removing the box mapping and running refresh shade removes the seams. I think this behavior is expected for box mapping, since it needs to divide the mesh to be mapped to different sides of the box.
Still makes me wonder why this would crash. How do you export?

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Interesting, removing the box mapping and even reapplying box mapping afterwards does fix the crash. The extracted analysis mesh still shows the weird seams and all, but the export to twinmotion does not crash rhino anymore.

I use this twinmotion button to export to udatasmith.

Thank you all!

This won’t help fix/solve you’re specific issue, but I use Twinmotion a lot, and most of the time I export my model as .fbx (obj is fine too) and then use import instead of direct link in Twinmotion. Might be worth trying just as an experiment with your file