http://www.autodesk.com/autocad-learningpath AutoCAD 2011 Tutorial: How to Convert 2D to 3D Objects
Learn how to convert 2D designs to 3D digital prototypes with AutoCAD’s state-of-the-art 3D modeling features. Many 3D models start out as 2D profiles that are extruded, lofted, revolved, or swept into 3D space. This video provides an overview of how to create 3D objects from 2D objects.
Source: Autodesk
