Airport 1.3dm (2.0 MB)
The surface isn’t developable. You can’t make a flat pattern that would bend into that shape without stretching or compressing somewhere.
UnrollSrf reports that the flattened surface is bigger than the original.
What is it you’re trying to accomplish?
You’re right, theoretically it isn’t developable, but practically it is if you know what I mean.
We’re trying to make an Aluminum composite panel for one of the Florida Airports that’s twisted when installed. I need unrolled pattern not to grow in the middle, like it doesn’t everywhere else. Otherwise, it’s just a tedious manual labor of redrawing the sides removing that extra 3/16" in the middle. Our panel size tolerances are within 1/16".
I’d just draw a 3/16" perpendicular inside the surface from the midpoints of the long sides and draw an arc through it starting on one long side end and ending on another. I’d do it for both sides and remove the "bulging "curves.
We did a mock-up of aforementioned panel and the long sides turned out to be not straight which was caused by “improper” UnrollSrf.
Since its not developable, UnrollSrf isn’t going to give you what you want.
Sounds like laying it out by hand may be the only way.
I use Squish to unroll aluminium sheet. It is not a one shot process, there is still a lot of checking to do.