The automated design process requires integration of structural analysis and synthesis in the commercial software for the kinematic and dynamic study. This needs computer algorithms for the automatic structural synthesis of the mechanisms, and requires a new description of the structural model. The paper presents a new approach of the structural model describing a mechanism as multibody system based on minimum number of bodies, kinematic and driving constraints. Generalized connections of 1RR and 2RR types are defined and a nine steps computer algorithm is introduced to obtain all the possible planar kinematic chains and to identify the distinct chains by eliminating the isomorphic variants and those containing rigid sub-chains. Based on the selected chains, by considering the fixed body and driving motions, all the generalized mechanisms are obtained. A particular case of three bodies and 2DOF in analysed. The method could further be extended for the general space.