Este mensaje ya estaba puesto en una consulta de dxf anterior. Espero te sea útil.
DXF TM group codes define all of the objects in an AutoCAD drawing. These codes are used programmatically by AutoLISP and ObjectARXTM applications to manipulate drawing objects, and by developers and users to import and export drawing data. The DXF Reference, previously part of this guide, is provided as a Help file, in HTML format, and as a PDF file for printing. These files are available from the AutoCAD Technical Publications Web site at