In order to improve digital mock-up, a tolerancing phase should be integrated in the
geometric models. However, in CAD software, tolerances are represented by annotations,
which are neglected as well as the tolerance impact. Thus, the system malfunction is
generated. For these reasons, in this paper a tolerancing phase is integrated in the
numerical model to form a realistic model, where worst case configurations of assemblies
are determined from the tolerances assigned to the nominal model. The proposed model
incorporates tolerances on CAD models in the case of planar face, cylindrical face and
planar face with non quadratic loop. In addition, the model ability to respect the maximum
material condition (MMC) and the requirement of datum priority order in the CAD models is
shown. Finally, functional requirement of a linear guide mechanism is inspected by using
the proposed model.