Hi Steve,
I’m currently working on a project in grasshopper that automates this process. In my case I need to take something between 1/3 and 1/2 for the neutral axis. Taking inner surface bends is only possible with thin sheet/small radii. What you can do is extract the inner surfaces in grasshopper, find the correct edges and move the surfaces to each other, join and unroll. That’s basically my process in short.
In my project it gets a bit more tricky as I have Z-bends, so I need to take both offsets and mix/match them together.
here is a simple example: (using lunchbox unroll)
unroll_forum.gh (15.0 KB)