Contact Manifold question

[xissburg]

What would the contact manifold between a cylinder resting over a box(with its circle base over the top face of the box) look like? How would you represent this manifold? Discretize the circle in some contact points?

Thanks.

[colinvella]

In my own physics engine implementation I sample 8 points on the cylinder end circumference hoping to get a reasonably shaped manifold when placing a cylinder on a box. Seems to work ok in practice.