Quality of 3d model in simple way translates into quality of final product, obtained from 3d printing. 3d CAx software give possibility to create enormous number of shapes – doesn’t matter solids or surfaces. The question is where is the frontier between quality of 3d model and a value for money of the completed print? Is it always necessary to create as good model as possible? This paper will focus on preparation of 3d models, based on primitives and will show connection between quality of mesh, its size and deviations and quality of obtained samples, in same manufacturing conditions.