Lately I'm designing a number of parts that are made from flat cut blanks and then rolled and welded at the seam. Currently, my workflow for this sort of part is to:
* Loft a bend between two parallel circles of the same size with a small (~0.015") cutout at one point on the circumference, creating a rolled ring
* Unfold this bend to get a flat piece
* Add features (holes, slots, etc.,) to the flat piece in the unfolded state
* Fold back up and create a flat pattern
This seems to work fine until I need to use a circular pattern - when I do that, the circular pattern applies to the unrolled state, so the cutout doesn't properly map to the cylindrical surface. I can approximate a circular pattern by creating a driven "circumference" dimension on the unfolded part and using a sketch pattern with an equation dividing the circumference by the number of pattern instances I want, but this seems less than ideal.
How should I go about designing these sorts of features?