AutoCad and Catia are both "design" software but the similarities end there. AutoCad is primarily for 2-dimensional drawings / design (yes, I know it has 3D functionality). Even Autodesk's (the company that makes AutoCad) 3D-modeling software, Inventor, isn't anywhere near the same (high level) class of Catia. Unigraphics would be up there, then ProEngineer, and then finally Inventor and Solidworks.Ah yes, I have heard of Autocad. Thank you for the clarification.