file is preceded by an integer number that is called a group code. A group code's value indicates what type of data element follows. This value also indicates the meaning of a data element for a given object (or record) type. Virtually all user-specified information in a drawing file can be represented in DXF format." See also Design Web Format (DWF) QCAD, an open source CAD application that uses the DXF file format internally and to save and import files LibreCAD, a version of QCAD Community Edition ported to Qt4 Open Design Alliance (originally called OpenDWG) ShareCAD, a free online CAD viewer that supports DXF, among other formats References External links AutoCAD DXF Reference (from Release 14, 1998) (PDF version from 2012) AutoCAD DXF File Format Summary. Annotated example DXF file AutoDesk Online DXF File Viewer. 1982 introductions DXF Autodesk products DXF