Depending on what you want to do, Bowler Studio is something you might want to play with.
It's a FOSS robotics software toolkit; you can model the entire robot and simulate nearly every aspect (including physics and servos and whatnot). Using it you can design, test, print, and assemble in a relatively nice fashion.
I mostly use BowlerStudio for 3D printing CAD stuff, but it does a lot, and since it's free I think it's worth playing with.
It's a FOSS robotics software toolkit; you can model the entire robot and simulate nearly every aspect (including physics and servos and whatnot). Using it you can design, test, print, and assemble in a relatively nice fashion.
I mostly use BowlerStudio for 3D printing CAD stuff, but it does a lot, and since it's free I think it's worth playing with.