Me and 3D design software really don't get on. Pay close attention to the top surface and bottom surface of the topmost bevel gear. It is a solid part, made out of one bit of metal. Supposedly.

https://www.dropbox.com/s/49um246rzj9s0yu/wtf%20gears.avi

Probably some sort of optical illusion.

Probably. :|

I like the way it simulates the heat generated by the gears grinding against each other.

It's not an illusion. And the heat, as you call it, is the software telling me there's a collision. It's supposed to be turning the second gear, but for some reason it's decided not to and just complains that they're trying to occupy the same space.

Looks fucked.

Have you completely constrained the bottom gear? Shouldn't the bottom gear have the rotational axis around the gear axis free? What 3D software are you using?

collision detection in my limited and rapidly fading experience of some vague readings a long time ago is that it is computationally expensive and probably in the case of something like meshing gears prohibitively so unless you have access to some kind of super-computer. That's why in 3d games (e.g.) you can not move through a wall, but you can stick your arm through it (and annoyingly, get protruding body parts shot or even stuck). You're probably better off manually timing out the gear meshings by trial and error/maths.

Nope, not constrained. It's Solid Edge. I ended up abandoning that assembly a few days ago. Still got loads to do for this thing and it's due in on Friday :-(