[ODE] force feedback

[George Manolaros]

hello,

I'm trying to get force feedback from a contact joint..

it works fine, but to my surprise the f1 and f2 are always counterforces
(f1=-f2).

the manual says that f1 and f2 are the forces that the joint applies to 
body 1 & 2 respectively..

the question is: 
_where_ are these forces being applied? 
At the center of mass or at the contact point? 


i know that the obvious answer is at the contact point (since f1=-f2).
But such a force should generate torque. 

i seems more logical to me that ODE should decompose the total force 
applied by the joint to a central force (f1) applied to the center of 
mass and a tangential force generating torque (t1).



can someone please clear out the exact nature of the forces? 

thank you,
George