[ODE] Surface normals per object when colliding

[Joost van Dongen]

I am writing my own code to resolve collisions and use ODE for collision 
detection. Now when I get a collision, the only data ODE gives me is a 
number of dContactGeoms. dContactGeom contains a vector normal to the 
contact surface, but I am really looking for the two surface normals at the 
two colliding objects. How can I get these?

Also, what exactly is the meaning of the normal in dContactGeom? In which 
direction does it point? Towards the first or the second colliding geom? How 
is it calculated?

Thanks in advance!
Joost van Dongen