[ODE] How terrain collisions are handled.

[Jon Watte (ODE)]

> I see that ODE uses a contact joint, and I see how this would work for a 
> collision between two free bodies, but what contact parameters are used 
> for collisions of a free body to fixed immovable terrain?

Attach the contact joint to the colliding body, and to NULL. 
Conveniently, the "body" field of a fixed geom is NULL.

Cheers,

			/ h+