[EricH]

Originally Posted by Cory

Traditionally, a true omnidirectional drivetrain allows translation in the x and y axes as well as rotation about it's center point, at the same time. A swerve drive will not allow you to do this. I don't believe a mechanum drive will either, but to be honest I haven't paid an ounce of attention to them beyond that cool Airtrax video.

A mecanum can theoretically rotate while translating. It also drives like a four-wheel with all the wheels independently powered. (In fact, driving like a four-wheel and only using the mecanum for short distances is possibly the best way to use one.)