Perhaps you could import the inventor files into 3d studio, and then export using 3d studio in a format that Maya supports. 3ds Max has a few other export options, so one of them might be compatible. Also, there is a program called Milkshape 3d that will open a .3ds exported from 3d Studio (and will not open .MAX) and save to a
ton of formats, pretty much sure to work. free trial:
Milkshape
And I'm wondering, why Maya?