Mechatronics
Enclosures and frames in which components, cable looms and cooling all have to find their place, and where the fixing points have to be right to the millimetre.
The shape is rarely the problem here; the positions are. Holes, press-in fasteners and mating faces have to line up with each other, including after bending and welding. So during preparation we look at the order of operations: which hole before bending, which face after.