Help - how can I flatten a shell structure?

Hi, I want to flatten a shell structure I’ve created with grasshopper and rhino. I do not want to ‘Make2D’ - I want to keep the entire structure as is in order to laser cut it and bend it into shape after. I can’t seem to find the tool to do this,. any help is appreciated!

Hi Lindsay,

Did you explore the UnrollSrf command already? It might be what you are after.


I’m assuming your shell structure has a pair of surfaces with a small space between them.

One approach is to extract one of the surfaces and use UnrollSrf to unroll it. UnRollSrf requires that the surface be “developable”, and a surface needs to be developable if it is to be cut flat and bent/rolled into shape without additional forming.

A refinement is to use TweenSurfaces to create a mid-surface between the two surfaces of the shell, and then unroll the mid-surface.

Thanks for your help @Willem and @davidcockey! UnrollSrf is what I need, I realize I had a doubly curved surface before and so it wasn’t working for me. Do you know if it is possible to extrude this curved surface, almost like an offset, rather than an extrusion in one plane? I’m trying to get some thickness to the structure.

Thanks for your help, I am pretty new with Rhino still. tskin0.3dm(1.4 MB)

OffsetSrf Use the solid option if you want a solid.

It might be worth while for you to go through the free Rhino tutorials. They are listed under Documentation on this page:

Example attachedthickDC.3dm(5.8 MB)