Nailing and Pinning: Adding Constraints to Inverse Kinematics

Greeff,M.; Haber,J.; Seidel,H.-P.

Inverse kinematics is commonly applied to compute the resulting movement of an avatar for a prescribed target pose. The motion path computed by inverse kinematics, however, often differs from the expected or desired result due to an underconstrained parameter space of the degrees-of-freedom of all joints. In such cases, it is necessary to introduce additional constraints, for instance by locking a joint's position and/or rotation.
We present a method to fix a joint in terms of position and/or rotation and explain how to incorporate these constraints into the inverse kinematics solution.