You can sell your autocad .dwg . Dxf files. You can sell only your creations( please see terms for detail rules) your drawings, models can not contain things that you have not created and for example blocks created by others, parts of drawings, models created by someone else. Your drawings , models also can not contain any third party information for example company names, addresses , people names, reserved names and symbols, etc. You can not copy someone else drawing, models and ideas to which he has legal right ownership. Any voilolation of site terms and rules and copyrights can be prosecuted.