@Dark samurai
yes i think since AutoCad 2004(if im not wrong) you´re able to draw in 3d... in AutoCad 2006 and 2007 they´ve improved the 3d part
@Lawrence
AutoCad saves to .DWG and .DXF and some others. but they´re probably useless for our needs.
About exporting yes, it exports to 3DS and some others that I dont know what is for.
@ego
.DXF is the format that AutoCad 2004 and below uses to save.
In my opinion it would be great to have a plugin to export autocad stuff to 3dgs, in 3dgs (although its easier) I dont like very much the fact of Dragging and Dropping the blocks and stuff, typing the coordinates manually gives me more control of the stuff im creating.