Adding thickness to polysurface

Rhino Rhino for Windows
1

Hi! I have this polysurface (it a part of a cap) and I need it to be exactly 1.1 mm thick so I can 3d print it. I’ve tried capping it and using shell command - didn’t work well. Then I tried offsetting surface inwards but it also had a few naked edges. Is there any simple way to do this?

Zrzut ekranu 2026-05-14 123016
Zrzut ekranu 2026-05-14 123016947×702 171 KB

cap forum.3dm (1.4 MB)

brvdln (Brv) 2
2 Likes
3

Thanks, that’s interesting and I’ll probably find it useful at some point but for this model I need it to be closed solid polysurface instead of mesh so I can continue working on it

4

Looking at the image, if you want to continue working with NURBS and the issue is creating the shell, one approach I would use — since this is essentially a geometry that can be solved with a revolve — is to work directly with the curves: create an inner offset based on the thickness you want, then perform a 360° revolve.

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@Aleksandra_Podwalska Nothing, I opened your file and a revolution wouldn’t work well. I recorded a video showing how I did it, I hope it can be useful for you in the future.
cap forum.3dm (1.3 MB)

I simply trimmed the intersecting surfaces against each other.

6

So the question is why is this pretty simple model not shelling easily…

After hacking it a bit I have these tips:

  • Do all of your tiny fillets right at the end, do not make them part of the base revolve. It should be able to handle them, but at least without starting from scratch I had to remove them all to get it to work.
  • Make sure planar surfaces are merged into a single actual simple plane instead of separate lofts or whatever that was.
7

Thank you! Aplied the tips and it works well now

8

watch the video, I explain how to get a nurbs result as well.