Vehicle Physics
(Here’s an e-mail I just sent that I thought might be of general interest.)
Well, I tried creating rigid bodies for wheels. They have nice traction and braking behavior but I ran into other problems. At high speeds (~60mph) the wheels would lose alignment. Perhaps this could be mitigated by using more iterations and/or smaller time steps. Another effect I didn’t anticipate is wheel tunneling. Now that can be reduced by ray casting, but this means the wheel won’t keep up with the chassis. I guess I could put in special logic to slow down the entire vehicle, but I didn’t try that.
I went back to my ray casting model and tuned it a bit more. I found a trick that really improves handling. Basically, I just offset all traction, braking, and friction forces up from the ground. The helps to diminish roll and pitch. This can’t easily achieved with rigid body wheels.
Anyhow, it was an interesting experiment and I’m glad I tried it.