It is basically AutoCAD 2002 with 2D mechanical add-ons. It contains things like standard fasteners, standard parts. Drawings that conform to standards (ie ISO, ANSI, DIN etc...). It has built in BOM and ballooning capabilities, dynamic block editing with auto-hide functions. Intelligent dimensioning and GDT. Better viewport creation and updating (lends itself to paper space layouts better than vanilla AutoCAD. We use it here and have used it since AutoCAD 13 when it was called Genius 13 (before Auodesk purchased it).
