Attached is a jpeg to show my concern cited in my question, the idea being to "be able to recover" the flattening of this pierced silt face... and send it to the plasma for cutting, quite simply, but it fails!!
Doing the repetition on the unfolded is surely easier to do than on the volume (since the normal of your repetition changes with each occurrence in the 3d)
It is quite possible to make holes that are square to the surface and this at any point on the surface where you made the first hole.
On the other hand, each hole is to be made by hand, no automatism possible. You have to make a sketch that allows you to make the plan of a hole + a sketch of the hole and a removal of material for this hole. Repeat the operation for each hole. On the other hand, I don't know what it will do when unfolding.
I'm in the 2019 version
Kind regards
PS: AMHA the non-unfolding has nothing to do with the holes since even without holes I didn't manage to use what you put for the flattening. You have to wait for my fortich colleagues to tell you how to flatten your bar and AMHA you have to remove everything that is not the bar since you gave us a PART and not an ASM. In addition, on occasion, someone can explain to me why your bar is not treated from the beginning as a sheet metal while Pierre 32 starts from mechanically welded.
I'm thinking here of the recent tutorial of @ac cobra presented at the challenge
If you want to keep the same modeling principle to get your holes, you can use a Boolean operation as said @gt22
Instead of doing a removal of matter you create a body according to the same parameters. Then during the snooze operation you select "Body" instead of "Function" And finally you do a Combined/Subtract from your Stringer minus the repeated bodies.