How to bend a surface without changing the size?

I digitized some plane templates and now want to build a 3D model from this (sheetmetal) planes. Therefore I must be able to bend these planes, but it is very important that the dimensions and shape of the surface stays the same. (So unrolling the surface again should give the same plane as where I started with.) Can someone give me some suggestions, please?

Have you tried using the Bend command?

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Bend | Rhino 3-D modeling (mcneel.com)

Hi Martin,

Yes, I did try the bend command. In my case however this does change the length of the edge curves. What I did not mention is that my surface is not a nice rectangle shape, but it’s a loft / 2 rail with curved “rail curves”. (It’s a side panel of a small boat hull.)

Please post a file with the relevant geometry. It’s much easier to help

bending example.3dm (55.0 KB)
Here is a file with 2 surfaces. The loft surface should follow more or less the shape of the bottom at that side.

Is there a reason not to start from the other side and model the boat and then unroll?

bending example.3dm (291.8 KB)

Yes there is. The measured templates are unrolled surfaces, and the idee is to engineer an exact copy from this templates.