If anybody want to learn the File Structure of DXF File read this
Talking about the dxf file AutoCAD DXF (Drawing Interchange Format, or Drawing Exchange Format) is a CAD data file format developed by Autodesk for enabling data interoperability between AutoCAD and other programs. DXF was originally introduced in December 1982 as part of AutoCAD 1.0
Structure of DXF File Format
A.) HEADER Section – General information about the drawing. Each parameter has a variable name and an associated value. Example of Header FIle is
Beginning of HEADER section
0 //Group code
2 //Group code
Repeats for each header variable
9 //Group code
$ //Name of Variable
//Group code for every Variable
//Value of Variable
End of HEADER section
0 //Group code
ENDSEC // End of header section
B.) Class Section- Holds the information for application-defined classes whose instances appear in the BLOCKS, ENTITIES, and OBJECTS sections of the database. Generally does not provide sufficient information to allow interoperability with other programs. Example of Header FIle is
Beginning of CLASSES section
0 // Group code and its Description is Identifies beginning of a CLASS record.
SECTION // Label
2 //Group code and its Description is Name of class
Repeats for each entry
1 //Class DXF record name. These should always be unique.
3 //Application name
90 //Proxy capabilities flag.
280 //proxy flag
281 //entity flag
End of CLASSES section
So in the class Section Flags are Used.
C.) TABLES section – This section contains definitions of named items like
Application ID (APPID) tableBlock Record (BLOCK_RECORD) tableDimension Style (DIMSTYPE) tableLayer (LAYER) tableLinetype (LTYPE) tableText style (STYLE) tableUser Coordinate System (UCS) tableView (VIEW) tableViewport configuration (VPORT) table
Beginning of TABLES section
0 // Starting
2 // Tab;e
Common table group codes,
repeats for each entry
Table entry data, repeats,
for each table record
End of table
End of TABLES section
D.) BLOCKS section – This section contains Block Definition entities describing the entities comprising each Block in the drawing.
E.) ENTITIES section – This section contains the drawing entities,
F.) OBJECTS section – Contains the data that apply to nongraphical objects,
G.) THUMBNAILIMAGE section – Contains the preview image for the DXF file.