Skeletons are the underlying joint and bone hierarchies that let you animate your characters. Every skeleton has several parent joints and child joints, and one root joint. Parent joints are joints that have joints below them in the skeleton’s hierarchy. For example, an elbow is the parent of the wrist and the child of the shoulder. The root joint is the first or top joint in a skeleton’s hierarchy. For more information on setting up skeletons, see Skeletons.
You can use the following methods to animate a skeleton: forward kinematics (FK).
With forward kinematics, you transform and key joints directly.
Forward kinematics are useful for creating detailed arcing movements, but not very intuitive for goal-directed movements. For example, you can easily use FK to animate the rotation of an arm at the shoulder joint, but not the arm reaching for a glass. For more information on FK, see Forward kinematics (FK).