Today I got to see both the autodesk packages MDT and Inventor. Instantly I realized the confusion Autodesk is in , Since I am working on a project which requires studies of almost all of the available MCAD software , and studied proe, sw before. The MDT introduces the parametric concept and surely autodesk had to develop this package so as to compete with the then sprading Parametric design market revolutionized by PTC. So is the case with the Inventor.The motivation behind this software is clearly SW from Dassault which is rich in its user interface and one can learn it quickly as almost everything in SW becomes trivial and so easy.(extrusion,sweep and loft operation to name a few). The study of autocad,MDT and Inventor in the same order will give oneself the insight into the history of development of CAD and the logical explaination of why the other software came into being.(eg. autocad : - 2D drafting,No parametric no constraint based with little bit of 3d operations, MDT : -3D drafting but not solid modeling. Inventor : a solid modeler.) regards, Yogesh Joshi.