“Object norms” are measures of distance for rigid body displacement in the plane or space. These norms are independent of the coordinate systems or metrics used. Since their introduction in 1992, they have been effectively used in several applications including computational kinematics, precision design, and robotics. This paper deals with the formulation and study of the time differential form and properties of these norms. A local linearization based on the differential forms of object norms is also independant from coordinate systems or their metrics.