Hello all. I have some critters that I move/steer using forces on either side of them parallel to their orientation, i.e. just a like a tank and it's tracks.

Given a steering force (i.e. a vector pointing from the vehicle centroid in the direction of ideal movement toward some goal), what would be the best way of decomposing that force into two forces, one for each 'track'?

The simplest option is a stop-turn-forward-stop-turn-forward-etc sequence, stopping whenever the orientation needs to be modified. Of course I would like smoother movement than this.

The main complication I can forsee is if smooth movement is dictated (i.e. left=0.5 right=1, a slow arcing turn toward the left), but that movement would cause a collision and it would actually be better to stop and re-orient. How on earth to handle that?

Perhaps rather than a steering force I should just pass a target location to the locomotion module, but then, same problem, how to decompose the distance vector to the target into two 'track' forces?

Any ideas or links to resources much appreciated.

Cheers,

Check out Accurately Simulating Movement of a Tracked Vehicle in 2D Space.

Also, if you can grab a copy of AI Game Programming Wisdom 4, Chris Jurney wrote a good article on how they did vehicle path planning in Company of Heroes. This doesn't help you with the force issue, but rather with the "can/should I do that here?" issue.