I use AutoCAD 2005 (started on R12) to design/draw and reverse engineer big-rig truck exhaust systems and components (2.5" dia. - 7" dia. tubing) and to design machine replacement parts and add-ons to our existing production machines in the shop. Everything is 2D, I have only messed around twice with 3D..... so far. (I'm waiting for Autodesk to feel sorry for me and send me a free upgrade to Inventor!)