Inverse kinematics

Inverse kinematics, or IK, is a technique that calculates the required or optimal motion of a connected system of objects to arrive at a certain destination. In robotics, IK can determine how a robotic arm should move so that an actuator at the end of the arm is correctly positioned. In 3-D animation, IK can be enabled in animation software, so that movement of a child joint in a hierarchical character rig naturally affects parent objects.

For example, when animating a 3-D human character with IK enabled, an animator can raise the ankle joint of a character, and the shin, thigh, and knee joint naturally moves and rotates.

The opposite of inverse kinematics is forward kinematics, where a hierarchy of objects must be manually animated from parent to child. Forward kinematics could animate a leg, rotating the thigh at the hip to raise the knee, and rotating the shin bone at the knee joint to position the ankle.

Actuator, Animation software, Computer acronyms, Hierarchy, Rigging, Software terms