[ODE] Contacts and multiple updates per frame

[Jon Watte]

> I have tried this too, and had good experience in my simulations, 
> however I repeatedly ran into problems with contact joints. The problem 
> seems to be that ODE behaves badly (sometimes) when a contact joint is 
> kept for more than one update (probably because thebodies are already 
> seperated again in the later updates ?).

You have to COLLIDE AND STEP for each time (and empty the joint group). 
Running more than one step with the same contact joint is not going to 
do the right thing (as you found), and it may also allow tunneling if 
you find you step many steps in a row without collision.

> however, this brings down the speed to a crawl, as collision takes a lot 
> of time.

You should profile your collisions and figure out why. For example, the 
collider bits help a lot in avoiding things like static trees colliding 
with the static ground. Also, make sure you use a HashSpace space, or 
better for your world space; the SimpleSpace is not very efficient.

Cheers,

			/ h+