Drawing Interchange File Formats
ASCII DXF File Format
General File Structure
Essentially a DXF file is composed of pairs of codes and associated values. The codes, known as group codes, indicate the type of value that follows. Using these group code and value pairs, a DXF file is organized into sections, which are composed of records, which in turn are composed of a group code and a data item. Each group code and value are on their own line in the DXF file.
Each section starts with a group code 0 followed by the string, SECTION. This is followed by a group code 2 and a string indicating the name of the section (for example, HEADER). Each section is composed of group codes and values that define its elements. A section ends with a 0 followed by the string ENDSEC.
It may be helpful to produce a DXF file from a small drawing, print it out, and refer to it while reading the information presented next.