File Extension T4G File Format Tommy Software CAD Draw File T4G stands for Tommy Software CAD Draw File. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Compressing Old Files Stop bit problem: USB to Serial Converter attached to motion controller, unable to set for 7-E-2 create drawings???