Output File Contents

This is an ASCII file, and is record structured. The records are organized in pairs and these are called groups. Each group contains a group code (an integer), and a group value that is in a format that depends on the group code.

A DXF file is made up of four sections:

• Header. This is preceded by a number of comment lines (as suggested in the NEDC recommendations). This includes the units employed in the drawing, and the date the file was formed. The Header section itself includes the $LIMMIN, $LIMMAX, $EXTMIN and $EXTMAX variables to specify the limits of the drawing and its extents.

• Tables. This section contains an LTYPE line types table defining the definition of the line patterns available to the Entities section. It also contains a LAYER and a style table.

• Blocks. This is empty.

• Entities. This contains all of the graphical elements of the drawing and their attributes. The entity types are LINE, CIRCLE, ARC, TEXT, POLYLINE and VERTEX.

  Note: Sometimes the first three sections are omitted, depending on the type of data and the purpose for which it is to be used.