Agriculture engineers face the task of developing projects of large-sized agricultural equipment (combines, tractors, etc.). This equipment should work in quite difficult conditions with high loads as well as providing the interaction of individual components and assemblies of this equipment. It is often not possible to create prototypes of the designed model in full size because the created machines have large sizes. Therefore, computer simulation is important for engineers. The process of simulation has the added value of optimizing the parameters of the equipment. The technique of optimization is using simulation calculation and optimization of parameters of agricultural equipment by converting the three-dimensional geometric models of computer equipment, developed in CAD-systems, specialized software package. The purpose of the research is to analyse the tools and methods of automatic construction of three-dimensional computer geometric models and optimization of the parameters of the simulated equipment.