Recognizing the construction methods of (piecewise) polynomial or rational curves and surfaces are of great importance, e.g., for geometrical data exchange between two different modeling systems. Paper aims to find conditions that would determine geometric shape of object from set of input curves and surfaces. These conditions should be able to detect: (1) whether a curve segment is a line, a circle, a circular arc, a ellipse, a elliptic arc or a planar curve; (2) whether a surface patch is a plane, a sphere, a cylinder or a cone; and (3) whether a surface is constructed as a surface of revolution, a extrusion, a ruled/developed surface or a generalized cylinder. The detected geometric features could be added to CAD system using their native CAD API. This would be achieved by choosing appropriate model parameters and creation method. Input is received in form of IGES files through comprehensive IGES Reader programs developed to process input geometric model.