:p
thanks
fusion > your right BUT in the picture you've send the tank is jumping, that means that the tracks & wheels have the same speed ( gravitional ) so they won't come of.
The situation you talk about is quite different, the tank ( mine ) is hanging between the rocks ( or whatever

) and as in real life the tracks will come of, if you ever get the chance of viewing a tank crossing a trench, you'll see what i mean. ( these are the occasions where tanks can loose their tracks )
At the end of the movie the moment the tank is riding on the concrete block you'll see that the track @ the end loosing > that's where I need the Lscript for - the chain is really driven by the front sprocket ( I'm not joking ) but because of an error in the expression i've used the front sprocket slows down as soon 1 or more wheels are loosing ground & hence looses the tension on the tread - if you watch carefullly this happens a few times ( it's still a WIP )
also the first & last wheel can't stop turning when comming of ground because of the chain running over it
maybe good to know that I used only 1 motionpath ( the body ) all the rest are expressions & dynamics