A generalization of dynamic constraints

This paper presents a constraint method for physically based computer graphics models, based on the constraint stabilization method of Baumgarte and on the dynamic constraints of Barzel and Barr. These new constraints are called generalized dynamic constraints (GDCs). GDCs extend dynamic constraints to obey the principle of virtual work and to fulfill time-varying and inequality constraints. The constraint forces of GDCs are computed by a sparse linear system and are proportional to the Lagrange multipliers of the constraints. GDCs are used to assemble deformable computer graphics models and to simulate collisions between the models.