I have a bit of a unique problem I'm hoping to be able to model a solution to. Without going into too much detail about the job, I essentially need to collapse a rolled plate.

Scenario:

Roll a piece of plate into a tube, say 24" diameter. 

After rolling, collapse the plate or "over roll" it into itself down to say 20" diameter. 

Now I have used a helix sketch to more or less represent the collapsed position with alright accuracy, but now I have sections that will be cut at an angle.

Now imagine that tube has a straight cut at one end and a 15 deg cut at the other end. Simply extruding the sketch of the coil up to the angle cut will be an inaccurate representation as the 15 deg end will have material sticking out with collapsed. In this attached image I drew in what you should expect from collapsing the tube vs what an extrude creates.

Is there some sort of manipulating feature that I can use to "squeeze" this rolled tube? It gets much more complicated with 2 angled cut ends actually being welded to create a tubing elbow THEN collapsing it down, but I figure if this can be solved I could adapt it to the elbow.

Thanks in advance, I hope this makes sense