The kinematics and dynamics of planar four-bar linkages are important topics in mechanical engineering. Humanoid movement is calculated through unity inverse kinematics. The study of motion can be divided into kinematics and dynamics. The Inverse Kinematics problem can also be approximated using heuristic methods. There are two main descriptions of motion&colon; dynamics and kinematics. The Earth frame is a convenient frame to express aircraft translational and rotational kinematics. No inverse kinematics or predictive calculations are required. There are many methods of modelling and solving inverse kinematics problems. The Jacobian inverse technique is a simple yet effective way of implementing inverse kinematics. Numerous different approaches have been used to model debris-flow properties, kinematics, and dynamics. Feinberg studied the kinematics of such particles according to special relativity. Character animation was made possible with motion editing for inverse and forward kinematics. However, it is a simple consequence of relativistic kinematics. He proceeded to kinematics of rigid body motion. Einstein originally framed special relativity in terms of kinematics (the study of moving bodies).