Full body IK uses multiple levels of hierarchy. These levels of hierarchy are used to group your effectors, joints, and even animation keys according to the anatomical structures of your character’s body. When posing your characters with FBIK, you work with your character’s FBIK effectors and skeletons. When animating your characters with FBIK, you work with your character’s body parts and character sets.

When you add full body IK to your character, the following levels of hierarchy are created:

• A FK skeleton and a set of FBIK effectors are created for your character, and your character’s original skeleton becomes its input skeleton. See FBIK skeletons and effectors.
• Each of your character’s FBIK effectors and FK joints are made members of a body part. See FBIK Body Parts.
• A top-level character set is created for your character and a series of subcharacter sets are created for each of your character’s body parts; all to house your character’s animation keys. See Character and subcharacter sets.