Unfortunately there is no un-bend or flatten tool, only a bend tool. Also unfortunatly all features that you add to your part after bending it would be removed if you un-bent the part in the parts history.

Sheetmetal tools / a flatten tool has been discussed and asked for many many times over the years, but so far there has been no visible progress.

My work around is to extrude the sheetmetal sections I need, or create a solid block, add the outside radius, then use the core tool to remove all the sides that I want open leaving the material thickness that I want. I then use the extrude hole tool and trim tools to add features. This method allows me to easily change material thickness while maintaining overall outside dimensions.

The last big (sheetmetal) project I worked on used a hex perf pattern that was then bent around a large radius. To create that I made a simple block, extruded the hole pattern into the block, and then bent the part with the bend tool (which is very buggy, and would only bend the part in the wrong direction which meant that after the part was bent I then needed to mirror it to get it going in the right direction). I also find that beyond a certain number of bends on the same part the tool becomes completely unusable as it refuses to bend parts in the direction that you want, or to a radius that you want.

As far as unfolding, I don't. Instead I hand over a STEP file to my sheetmetal vendor who then unfolds in SolidWorks. That way I define what I want the finished part to look like, and the vendor is responsible for getting there. If needed I add a 2D drawing of the finished 3D part with call outs for critical dimensions, like edge to hole centers so that the vendor knows what items are critical. One other trick is to replace Sharks arbitrary part number with your part number, and similarly rename any standoffs / inserts with the appropriate PEM part number.

Thank you Martin, surfaces aren't my strong suit, I had no idea you could create iso lines let alone measure them.
-dale