# Roll surface like piece of paper

I have a shape that will be cut from a flat piece of metal and then rolled in one dimension (as you would roll a piece of paper) to create a three dimensional shape. I need to be able control the roll (without distorting the dimensions of the shape) with more precision that I can figure out how to achieve with the bend command. So, for example, I would like to roll it at both edges but in an asymmetrical way. Any suggestions?sheet roll.3dm (418.0 KB)

Hi Kira - I think FlowAlongSrf will help here - make a cylinder for example- and a flat plane made by UnrollSrf of the cylinder. Flow the object from the plane to the cylinder - with History recording turned on, you can modify the position. IN the attached file, I just flowed a bunch of curves to make it faster but the idea will work with the polysurface. Try rotating the flat red curves in Front using the gumball.

sheet roll_PG.3dm (399.3 KB)

-Pascal

Hi Pascal. I looked at your file. The problem w flow along surface is that it appears to distort the shape. I need the shape to stay exactly the same dimensions (so that the base dimension not get any wider, narrower, taller, etc) as it gets rolled. When I measured your lines, they were slightly shorter than those on the original surface. Do you have any other suggestions for solving this conundrum?

Hi Kira - I don’t know that there is any way to guarantee the dimensions will stay exactly the same using the Flow stuff - on the other hand since we are dealing with a cylinder, just plain Flow, with curves, might do it - I don’t know how that will handle the sizing, I’ll try it and get back…

Flow seems better…

sheet roll_PG_Flow.3dm (392.9 KB)
-Pascal

Hi Pascal,
It is a bit more complicated than that. I want to bend it in ways that are not bound by a cylinder… you will see what I mean in the attached file. The overall size of the shape increase by 3.4sf after it has been flowed. Is there some other strategy I could try?? Thanks so much! roll surface 2.3dm (253.9 KB)

If the result was only a diagonal cylindrical roll section, you could cut it from a cylindrical tube.

Or create it from a single cylindrical surface, with projected/pulled curves, and then make it thicker, perhaps though a sweep1 along it’s edges, and using lines perpendicular or normal to the surface.

If the bend is a compound bend, such as from a stamping, perhaps you are going to have to free your mind from the idea of bending it, and either cut it from its final shape or build it from curves that describe its shape, and then build surfaces from those curves.

Although it would be harder to control, you might be able to do create an otherwise difficult shape from cage editing another shape. Though, the result will likely have lots of nodes in its actual surface.

Let’s try Squish then… Try:

1. Squish the deformed panel.
2. Place the outline curves from the leaf shape on the result.
3. SquishBack these curves to thew 3d target surface.
4. Trim this surface with the SquishBack - ed curves (blue surface).
5.Check area… Not too terrible.

(BTW, the objects are very far from the origin - that will not help precision…I moved stuff to the World origin)

roll surface 2_Squish.3dm (797.2 KB)

-Pascal

[quote=“kirashelly, post:1, topic:31688”]
I have a shape that will be cut from a flat piece of metal and then rolled in one dimension (as you would roll a piece of paper) to create a three dimensional shape.
[/quote]If the metal is to be rolled with stretching or shrinking then the resulting shape will be a developable surface. DevSrf can be used to create developable surfaces from suitable edge curves. A developable surface can be unrolled using UnRoll or UnRollUV. Then a curve, etc on the unrolled surface can be transferred to the developable surface using FlowAlongSrf.

Your current surface is not developable. To create a curve using DevSrf the edge curves will need to be extended. The shorter edge will need to be either split at the inflection point, or the inflection point will need to be eliminated.