By the methods of the geometric 3-D simulation and the projection drawing, an influence of geometric parameters of a deforming roller on an area of a contact surface and a billet in the process of rotary drawing with wall thinning has been studied. A comparison of projection areas of the contact surfaces, calculated by different methods was carried out. The results of the study are in good agreement with known experimental data and can be used in the design practice of process equipment and processes of rotary drawing with wall thinning.