The IK Constraint Tag helps to get a more predictable behavior of the IK solver. Especially the 3D solver, since the angle limits constraint the set of possible solutions of the IK solver. It also prevents IK chains from making unnatural movements like over bending of elbow joints for example.

So it is always recommended to set up the IK Constraints for IK chains which use the 3D solver of the IK Handle Tag. It might make some extra work to set up the IK chain but it will pay back when you start animating or posing your character.

Properties

• constrain: Choose which rotation coordinates of the tags owner should be constrain. (only works for 3D solver)
• heading: Set the min./max. heading values the object can take.(only works for 3D solver)
• pitch: Set the min./max. pitch values the object can take. (only works for 3D solver)
• bank: Set the min./max. bank values the object can take. (only works for 3D solver)
• stiffness: Determines how much the joint bends. With a stiffness of one the joint doesn't bend at all.