When the shapes you want/need are hard or tedious to express in say Fusion360 (or FreeCAD, which is same type of software). As a simple examples, I needed NN c

When the shapes you want/need are hard or tedious to express in say Fusion360 (or FreeCAD, which is same type of software). As a simple examples, I needed NN concentric circles (plus some details) with increasing radii. In FreeCAD one can easily create linear or radial arrays of NN objects, but not an array where radius increases per instance. I would have had to create all NN instances and position them individual. If N was 4 I'd probably just do that, but not for over 10 - especially because it may change. Note that other graphical CAD softwares might have this particular operation (rotoscale array), but there will always be something which is not available. But 99% of my designs (mostly mechanical parts) are done graphically in FreeCAD. This despite being a programmer, and quite familiar+fond of Python.