They do. Inventor is a 3d parametric editor. You can make a simple gear, or you can make an engine and apply constrained motion as it would work in real life.

They do. Inventor is a 3d parametric editor. You can make a simple gear, or you can make an engine and apply constrained motion as it would work in real life. We call this an assembly. I have quite a few drawings that have over 100 parts in them. No big deal, so far? The problem is Autodesk Inventor wants to put a nag screen on everything you open, proclaiming "THIS IS EDUCATIONAL". That's fine for me so far... Until you realize that it opens up the "THIS IS EDUCATIONAL" for every part, and including the assembly file itself. 101 dialogs? No. It crashes after 70 or so. So, I went and downloaded a pirate copy. And l and behold, the pirate copy works better than the 'legit' one. (Solidworks is $175 for student, and Catia has no student option. Creo or ProE just stinks.)