I am mechanical engineer and I use parametric design programs since 2010. These programs allows the precise realization of 3D projects, both individual parts and assemblies, as well as the associative generation, based on the 3D models of the 2D execution and assembly drawings. These programs are made in modular form, including modules for 3D modeling of individual parts and assemblies, 2D drawing, modeling of sheet metal parts, import/export of various formats and photorealistic representation (rendering). Programs are used extensively in industry, in the design. The resulted files can be exported in different formats (.stl, .igs, .stp or other) that can be read by machine tools with numerical control and thus can be obtained physical parts. I also use dedicated software for FEA, which means that I can virtually test the 3D model, in order to find out if the real object will resists in exploitation.