library.creativecow.net/devis_andrew/AE_Inverse-Kinematic_2_300th Standard character animation in After Effects uses a process called 'Forward Kinematics' in that we animate down a linked chain - for example, upper arm linked to forearm linked to hand. To get animation we need to move the items down the chain one at a time. Inverse Kinematics creates a link back up the chain such that moving the hand would also move the forearm and the upper arm without breaking that link. This is a simpler and easier way to control animation and is often used in 3D programs such as C4D and 3ds max etc. and allows us to control the animation for the complete chain through a single controller.