3D optical scanning method, is employed to digital shape and geometric dimension analysis of fuel tanks. The following paper presents the application possibilities of the optical 3D measurement method for measuring and archiving dimensions of geometrically complex parts, on the example of a passenger car fuel tank in local company. Based on the conducted measurements, for a specific type and size of the population of fuel tanks, proposed model that classifies the geometric accuracy of the tanks produced in the production line. For the analysis and data processing different informatics techniques have been used. The main objective of theirs was to identify the possibility of implementing the system for automation of the measurement to the production line. The measurements were implementation at local company - a manufacturer of polymer tanks in the automotive industry. For most of the measuring points, the mean value of the measuring deviations ranged from -1 mm to +1 mm. The mean values of the standard deviations are presented for a representative deviation of the X dimension of 0.1; 5; 10; 15 and 20 mm were respectively: 0.014; 0.150; 0.172; 0.289; 0.340 mm. The dimensional shape assessment of the manufactured tanks is extremely important from the point of view of the automation of this task in the production line. The optimization of the measurement of tanks carried out in laboratory conditions was implemented on the production line. The main task of optical scanning for the assessment of dimensional conformity has not been used so far in factory. This is due not only to the cost of such systems, but also to certain limitations that have been resolved thanks to laboratory tests. The obtained results of the metrological inspection make it possible to identify significant dimensional and shape deviations of automatically manufactured tanks. The proposed use of artificial neural networks allows the production with a high quality of tanks accuracy with the minimum the number of scanned tanks in the production line. The paper also presents the possibilities of the computer software to analyze the deviations of geometrically very complex parts.