A manifold point is a contact point belonging to a contact manifold. It holds details related to the geometry and dynamics of the contact points. The local point usage depends on the manifold type: -ShapeType.Circles: the local center of circleB -SeparationFunction.FaceA: the local center of cirlceB or the clip point of polygonB -SeparationFunction.FaceB: the clip point of polygonA This structure is stored across time steps, so we keep it small. Note: the impulses are used for internal caching and may not provide reliable contact forces, especially for high speed collisions.