Design of parts and assemblies is done in Pro/Engineer (Parametric Technology Corporation). This allows three dimensional modeling of parts, drawing generation from part files, automatic drawing and assembly updating when a part file is changed, tolerance and fit checking, and many other features to facilitate design. We normally follow standards in developing models and drawings (see below links). The Pro/Mechanica module can be used to mesh parts and perform thermal and structural analyses. The parts can be handed off to fabrication electronically, to facilitate direct NC machining of parts from the solid Pro/E part geometry.