I find when I imagine mechanical designs I can get a reasonable intuitive grasp of mechanism and kinetics. It might be the way my mind works but for me I "feel

I find when I imagine mechanical designs I can get a reasonable intuitive grasp of mechanism and kinetics. It might be the way my mind works but for me I "feel" the parts more then see them. But I can't visualise with accurate dimensions, and for me I find that matters a lot in terms of manufacturability. Even very simple designs I usually end up making several iterations on paper or in cad. It's only after dimensioning, doing some basic calculations (say, will this bit be strong enough), matching to available stock and parts, double checking the tooling I have to make sure I can actually make the things I've drawn, looking for interference and so on that I know what the design is really going to look like. People who are really good, I think, naturally design parts to minimise setup time and with the jigs and workholding they'll need to make them in mind. I'm not there yet... I still snooker myself on workholding or order of operations reasonably often.