Planar motion is incorrect

[karenliu]

If your skeleton can only move in a plane (e.g. 2 translational + 1 rotational dof at the root link), the momentum doesn't seem to conserve in a passive simulation with zero external force. I believe that the problem has something to do with the joint type assumptions made in SkeletonDynamics. For now, please create skeletons with 3 rotational dofs at the root regardless it's planar or not.

[jslee02]

PlanarJoint is added at 8a4f429.

Momentum conservation test should be added for this joint type.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.