A significant share of total manufactured workpieces, obtained in the metal forming processes, are workpieces with a developed «thin» blanket and the ribs. Mathematical model, describing the deformation of a thin layer of metal, based on «sand analogy». Due to a number of assumptions, this model gives an approximate picture of the metal flow. It is very convenient for constructing a visual picture of the flow of metal when it is necessary to obtain not quantitative and qualitative characteristics of the process. For the simulation of plastic forming of workpiece has developed a software complex PARSHTAMP, using «sand analogy». It allows to represent: the contour of forging, the dividing line of metal flow, the pattern of the metal flow, the profile of the ribs, the spatial diagram of contact stresses.