Developing the virtual prototypes of novel products using commercial software leads to a unitary modeling of all the component mechanism types (linkages, cams, gears, etc.). The paper presents the analytic modeling of the bodies (cam, follower), considering the geometrical restrictions from the joints of the planar cam mechanisms, using the Multibody System Theory.Based on this, a unitary analytic model for all the types of the planar cam-linkage mechanisms can be obtained.