Flattening a helical compound curve to maintain accurate dimensions

presision glass final.3dm (1.4 MB)

Anyone know how to flaten compound helical curves to maintain accurate dimensions and radii?

I downloaded and opened you file. It is not obvious to me what you want to do.

How do you flatten something and maintain the radius?

Sorry, I have two helical glass panels in 3d and I want to take the convex curves from the panels and flatten them accurately as to maintain the true dimensions. If this isn’t clear I will try to explain further. thx Bob

My guess is you want to design curves on the helical surfaces, then determine a corresponding “flat” (planar) shape of the curves which will enable the curves to be wrapped around the helical surface without stretching or compressing… Do the curves cross? If so you presumably wish to maintain the angle of the curves crossing.

If so then a developable surface which the curves lie on is needed. A developable surface has single curvature everywhere, and can be unrolled flat without distortion. Unfortunately most helical surfaces are not developable. Unless another developable surface can be found which coincides with the curves it may not be possible to “flatten” the curves as you wish. If so that will be a limitation of geometry, not a limitation of Rhino.

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presision glass final.3dm (1.4 MB)

Wanted to take the convex borders of the panels along with the holes and project them flat retaining the dimensions of the helical surface and curves. thanks for your patience

Hi Bob - UnrollSrf on the outer or inner faces of the object should get you that if I understand?


UnrollSrf should work. I’m not seeing a helical surface. Looks more like a section of a cylinder to me.

Thanks David for your time, unrollsrf worked perfect

Thanks Pascal, worked perfect