This may just be "news" to me, but I was struggling today with making a complex solid cutter, which I would use to cut the required shapes into a model I was working on.
Now this is one of those times where it is easy to make the entire surface that you
don't want but difficult to make its mate.
A flash of blinding insight shone all around my Dodge truck as I was motoring down a dark country road
A voice in my head said "Wherefore dost thou not use thy easy-to-make-surface to first form thy difficult cutter, and then turn about and then thou canst use thy newly formed cutter as was thine intent?"
Simple enough. I'm getting quite a kick out of learning solid modelling. It is a different way of thinking from what I was used to, but its fun trying something new.