File Structure of Object Map Section in DWG File? - Programmers Heaven

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File Structure of Object Map Section in DWG File?

ktruongktruong Posts: 3Member
Hi All,

In my assignment I need to analize the DWG file structure and I have difficulty understanding the Object Map section, how the list of handle/file loc pairs is arranged! I have read the manual of AUTOCAD R13/14 DWG File Structure from OpenDWG.org, but still have no clue about that section. The following is the hexdump of that Object Map section, which I figured it out from the 3rd record of the Section-Locator Records of the file header of the DWG file (created from AutoCAD LT 2000 and contains 2 circles only):

In hex format:

00 6F 01 AF A0 01 01 15
01 11 02 11 01 15 01 0E
01 0E 01 12 01 11 01 12
01 0E 01 F2 0C 01 89 4C
01 85 0D 01 CC 4A 01 1A
01 A5 08 02 D3 45 01 9B
02 01 C4 44 01 D3 09 01
D1 03 01 B0 43 01 D3 40
01 A1 4A 01 DF 0B 01 B6
4B 01 D7 0B 01 9B 4D 01
D9 0C 01 D2 4B 01 EA 0D
01 B0 4F 01 F5 0C 01 CC
4C 01 B4 0E 01 F0 43 19
83 4A 05 2E 01 A1 08 0A
0D 00 02 01 D0

In binary format:

0000 0000 0110 1111 0000 0001 1010 1111 1010 0000 0000 0001 0000 0001 0001 0101
0000 0001 0001 0001 0000 0010 0001 0001 0000 0001 0001 0101 0000 0001 0000 1110
0000 0001 0000 1110 0000 0001 0001 0010 0000 0001 0001 0001 0000 0001 0001 0010
0000 0001 0000 1110 0000 0001 1111 0010 0000 1100 0000 0001 1000 1001 0100 1100
0000 0001 1000 0101 0000 1101 0000 0001 1100 1100 0100 1010 0000 0001 0001 1010
0000 0001 1010 0101 0000 1000 0000 0010 1101 0011 0100 0101 0000 0001 1001 1011
0000 0010 0000 0001 1100 0100 0100 0100 0000 0001 1101 0011 0000 1001 0000 0001
1101 0001 0000 0011 0000 0001 1011 0000 0100 0011 0000 0001 1101 0011 0100 0000
0000 0001 1010 0001 0100 1010 0000 0001 1101 1111 0000 1011 0000 0001 1011 0110
0100 1011 0000 0001 1101 0111 0000 1011 0000 0001 1001 1011 0100 1101 0000 0001
1101 1001 0000 1100 0000 0001 1101 0010 0100 1011 0000 0001 1110 1010 0000 1101
0000 0001 1011 0000 0100 1111 0000 0001 1111 0101 0000 1100 0000 0001 1100 1100
0100 1100 0000 0001 1011 0100 0000 1110 0000 0001 1111 0000 0100 0011 0001 1001
1000 0011 0100 1010 0000 0101 0010 1110 0000 0001 1010 0001 0000 1000 0000 1010
0000 1101 0000 0000 0000 0010 0000 0001 1101 0000

I would greatly appreciate if anyone can give me some explaination or show me where I can get info about it. Please contact me via my email: rquan @ geologic.com (remove spaces) if possible. Thank you very much.

Best regards,
Raymond


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