ASCII versions of DXF can be read with a text editor. The basic organization of a DXF file is as follows.
Header Section – This section contains general information about the drawing. Each parameter has a variable name and associated value.
Classes Section – This section contains information about application-defined classes whose instances appear in the Blocks, Entities, and Objects sections of the database. Generally does not provide enough information to allow interoperability with other programs.
Tables Section – This section contains definitions of named objects.
Application ID (APPID) table
Block record (BLOCK_RECORD) table
Dimension style (DIMSTYPE) table
Layer (layer) table
Linetype (LTYPE) table
Text style (style) table
User Coordinate System (UCS) table
(VIEW) View table
Viewport configuration (VPORT) table
Blocks Section – This section contains block definition entities that define the entities that make up each block in the drawing.
ENTITIES Section – This section contains the drawing entities including any block references.
Objects Section – This section contains data that applies to non-graphical objects, used by AutoLISP and ObjectARX applications.
Thumbnail Section – This section contains the preview image for the DXF file.
End of file.
DXF’s data format is called a “tagged data” format, which means that each element of data in the file is preceded by a number called a group code. The group code value specifies the type of data element to follow. This value also indicates the meaning of the data element for a given object (or record) type. Virtually all user-specific information can be represented in a drawing file in DXF format.
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