How to roll a planar surface along a curved developable surface


I am trying to roll a planar surface along a curved developable surface as though it’s a development but it isn’t working properly.

I have created two straight curves and an arc and joined them together to create one single curve. This curve is used as the section input for a sweep1. This sweep1 surface is a developable surface. I unrolled this surface using the unroll brep component from the free grasshopper plugin called lunchbox. I have drawn a curve in rhino over the development and used this curve to split the development. I have used the copy trim component to trim the sweep1 surface with the curve I’ve drawn in rhino. However this isn’t working properly as you can see as indicated by red arrows in one of the jpegs.

I think the problem has something to do with the copy trim component and the fact that the section in the sweep rail is made of two straight curves and an arc.

If you want to know the reason why I’m trying to do this it’s because I’m designing chairs that have a wing shape. This method of shaping the chair by unrolling the surface makes it a lot easier to design the right shape I want.

Thanks for your help

Rolling a planar surface (24.5 KB)
Rolling a planar surface Rhino.3dm (22.1 KB)

Like this?

Rolling a planar surface (25.1 KB)

It’s improved but its still not right. The rhino curve is curved yet the development has straight parts as indicated by red arrows.

Your target surface is an extrusion(ie: Sweep 1)which was made from degree2+degree1 joined curve.
So, that result of straight curve is not strange at all to me. It’s not the fault of Copy Trim but your target surface property.
Check this V2 attachment and you’ll know what I mean…

Rolling a planar surface (21.9 KB)

1 Like

Yes that makes sense that the copy trim target surface needs to be degree 3

Thanks for your help HS_Kim