# Unrolling rolled CHS

Hello there I am hoping someone can help solve the following.
I have a bunch of rolled pipes (planar, single radius) which are arranged to create a double curvature surface. All center lines meet and intersections between members have been resolved and modeled.
From a fabrication standpoint, the process we would like to follow is to laser cut/mark the scallops at the ends of straight CHS before feeding them to the rolling machine. In essence the fabrication process is the reverse of the modeling process.
I am trying to translate these single radius planar pipes with scalloped ends into straight pipes whose center line is the same length and where the scallops maintain the correct position. I have tried using bend but I am not sure how to achieve acceptable accuracy. I have found a way of doing it “manually” by extracting the trimmed ends and orienting them to a straight segment of the same length as the rolled pipe’s CL but its tedious and time consuming.
Any suggestions would be most welcome
Best
Gio

Tricky problem…if I understand it correctly.

Perhaps extrude the scallop border into a cylindrical shape and Unrollsrf that. Get an edge length of the pipe, shortest edge perhaps, and position the unrolled srf onto a planar srf of the appropriate length and width = diameter. DupEdge and combine all the bits back together…

Post an example file or picture to clarify the problem.

Wow:

http://www.abbreviations.com/CHS

Nick is a better man than I am… I haven’t yet visualized the problem…

-Pascal

something like this ?

…and wanting to know how to make the blue sections straight, while maintaining accuracy, so they can cut the scallops (the joint cut at the ends of the blue pipes which mate to the purple pipe ??) prior to bending the radius
?

Something like that is what I imagine… I guess maybe Flow from the curved centerlines to straight lines of the same length.

-pascal

Hey guys thanks for the replies. Now I am at home and i dont have images to show, apologies not sure how I forgot to add images.
Anyway. We solved the issue by creating a scalloped straight section at the intersections which is then joined to a rolled chs whose ends are simply cut straight. The radii are quite large so the loss of tangency would be negligible. A very interesting challenge nevertheless, will keep looking for a solution
cheers