Simeon Nedelchev
Detection computes nearby geometry.
Response computes the resulting forces or impulses.
The two stages answer different questions.
Bounding volumes reject distant pairs.
Detailed geometry handles candidate pairs.
Gap alone does not determine contact force.
Point, frame, distance, and geometry pair.
A candidate within a margin can have positive distance.
ncon and contact describe contact geometry.
mj_contactForce returns a contact-frame wrench.
Compare gap, force, and motion.
Changing collision shape changes the physical experiment.