So I've seen videos of parts like baring and "impossible prints" where they print their part and chip some supports away and it moves seemlessly. Just wondering if its a special printer like resin or fine dust and laser or just abs/pla? Or do they make it all fit with small gaps in their software like inventor?

any help or guidance would be great! videos are reccomended.

My printer: MakerBot Replicator 2x
Makerware
Inventor 2014 and 2015