i havnt properly read this thread so what im about to say might not tie in with whats been already said but, personally i could never build a robot on cad or anything in a million years, dont get my wrong i've used it before but for me its about doing loads of sketches on some paper and then making a cardboard mock up to scale- and then putting all the parts in the mock up and pretty much just building on from there.

depending on the way your building either box section chassis or the bulkhead way which ever, and how your cutting your materials by hand or by machine- personally cos i cut all my stuff by hand- don't get me wrong it takes alot of hard work lol but with loadsa cardboard templates to cut around -that i made from my mock up thats just the way i prefere doing things - near enough all i have is a cramped shed with a jigsaw, welder and just other basic tools nothing special so im happy enough doing most things my self but obviously theres certain things that i can't do so i get kenny or grant to do them for me.

so its really personal preference as to how you'd go about designing your robot