Replicating an existing polysurface

I am trying to replicate an existing polysurface imported from SolidWorks.
The original poly is highlighted.

I need to dispose of the ugly patchwork of surfaces jammed together. For this purpose, I Intersect’ed the original poly with a moving cutting plane to create a set of curves. I intend to use them to create a surface or a polysurface I can properly unwrap.

Ideally, I would like to use a single “sweeping” function to create a poly(surface) using the curves. I would expect a Loft could handle the geometry, but it failed miserably with my curves.

What is the most economical way of replicating a somewhat complex shape in Rhino?

Thank you,


PS: 3dm is attached

A.3dm (447.0 KB)

You’ve got this backwards. The Solidworks model IS modeled correctly, for production purposes using NURBS. “Make a bunch of sections and Loft” is not how to make ANYTHING in Rhino. You could probably use fewer surfaces to round off the outer edge, but it’s not really ‘wrong.’ I don’t know if making it as a single surface is better for unwrapping, I can’t see it with the singularity you’ll wind up with.

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Thank you for your input.

I do not necessarily need a single “loft” surface for a complex shape, I’ll be happy with a poly. However, I do need to control the edges/seams of the surfaces I plan to unwrap. The original SW polysurface does not allow me to unwrap itself properly in Rhino. 6.17.19235.15041, 8/23/2019 is not happy with the geometry, it produces messy results.


Hi Arsen - if you’re looking to do this for texture mapping purposes, then you can do more or less as you suggest, loft with Rebuild to a lot - say 64 - points, and then use this as a custom mapping object on the SW part.


Thank you, Pascal.

Please clarify for a noob.
Should I rebuild each curve with the same number (64) points and then Loft?

Could you give me any other general hints on how to “replicate” an SW shape in order to manually texture map it later anyway I want? I mean manually unwrapping the shape selecting the seams along the wireframe.

Thanks again for your help,



When the manual Unwrap is not working for me in Rhino, I create Meshes and do the unwrapping in RizomUV.

I would love to find a working solution inside Rhino 6 working with NURBS.


I think @pascal is referring to this:
(the last method shown in the video)

No remodelling needed, just create a rough, simple shape around your component that serves as a custom mapping object (UVs are then projected to your model I guess)
Cheers, Norbert

Ah, thank you, Norbert.