This project, which I derived from the tank tread example I got on Maxon's site, shows how you might rig up a tank tread to an actual vehicle. There are 2 "Axels" with two wheels a piece per tread. The wheel rotation is controlled by a null object and I just eyeballed it to animate with the treads. I positioned nulls at various points around the two wheels and included them under the axel - then I liked the points on the tank tread path spline to these nulls...so when the axel rotates and moves, it angles the nulls (which are lined up with the wheels), deforming the spline and the whole tank tread with it.
This animation (AVI file with MP4 encoding), shows the results - I had a null to move the whole "tank" across the plane, and then hand animated the 4 axels (moving them on the Y Axis and rotating manually, recording each frame) every 10 frames.
Here is the Zipped Cinema 4D File (Cinema4D R8.5)
update: Oh and here's another little animation of a tracked vehicle - with some camera mapping thrown in for good measure.
Quentin Preik2004/05/06