The urgency is the need to increase the level of automation at all stages of design. The aim of the study is to create a mathematical model and the creation of a program to automatically obtain information about the geometrical characteristics of the model details. Discusses a method of decoding information about 3d-model parts from the source file. The paper describes a mathematical model, algorithm and software solution to the problem of automatic analysis of the part geometry. As a result, created a program that receives information about the model, determines the possibility of reading the data, detects the surface and their characteristics, displays information about the surfaces of the model.