Graphical Class Hierarchy Node0 Trk::VKConstraintBase Node1 Trk::VKMassConstraint Node0->Node1 Node2 Trk::VKPhiConstraint Node0->Node2 Node3 Trk::VKPlaneConstraint Node0->Node3 Node4 Trk::VKPointConstraint Node0->Node4 Node5 Trk::VKThetaConstraint Node0->Node5