Revolute joint used in loops (1 rotational degree-of-freedom, no states)
Mechanics/Planar/LoopJoints
This is a joint where frame_b (right) rotates with respect to frame_a (left). The counterclockwise rotation is described by an angle phi. For phi=0 the two frames coincide.
Note, this is a special Revolute joint and it can be used in kinematic loops only. Exactly three joints of the palette LoopJoints have to be used in each kinematic loop.