Kinematics (from Greek κινεῖν, kinein, to move) is the branch of classical mechanics that describes the motion of objects without consideration of the causes leading to the motion.^[1] Kinematics is the study of the geometry of an object in relative motion. A large majority of mechanisms exhibit motion such that all links move in parallel planes. This type of motion is called two-dimensional, plane, or planar motion. Planar rigid-body motion consists of rotation about axes perpendicular to the plane of motion and translation—where all points in the body move along parallel straight or curvilinear paths and all lines embedded in the body remain parallel to their original orientation. Spatial mechanisms, allow movement in three dimensions. Combinations of rotations around up to three nonparallel axes and translations in up to three dimensions are possible depending on the constraints imposed by the joints between links (spherical, helical, cylindrical, etc.) ^[2]