Ahmad

Auto cad is a simple drafting tool any one with basic knowledge of computer & little aware of civil construction terminology. the programming consist of commands with single, double alphabets such as l for line, c for cirlcle,co for copy etc...where space bar also can be used instead of pressing enter.you can draft using only mouse, of only with keyboard with the help of x,y,z co-ordinates or you can use both for quick drafting.you will have usefull options such as orthognal mode, snaping to particular point options, tracking options for high accuracy. it is flexible with metric system and feets & inches system. export options help to further develop the project in other rendering & simulation softwares. 

AUTOCAD is a basic drafting tool which was earlier designed to draft fast & accurate drawings at the schematic stages. Later if you go indepth with the details such as  heights, structure, material calculation, quantities and automatic formation of schedule of openings with respect to the change in floor plans, these kind of advanced options are available in revit but for intial stages i prefer autocad as a good tool to present your ideas which can later exported to revit & develop the project accordingly.