[ODE] Can't seem to make parallel opposing planes

[Jon Watte]

>   dCreatePlane (space,-1,0,0,-1); 
>   dCreatePlane (space,1,0,0,1);

These planes are at the same location measured from the origin. 
The "d" part moves the plane away from the origin back along the 
surface normal; because the two normals point in different ways, 
and the "d" values are negative of each other, you move both planes 
in the same (world-space) direction.

Cheers,

			/ h+