UPDATE 2: Section 2 mapped! Still unknown what it does.
UPDATE 3: Check out my post regarding visibility of tunnels affected by section 4 flag 128.
UPDATE 4: Flag 64 completely described! Check it out below.
There seems to be almost no documentation on GTA III's CULLZONE.DAT anywhere other than at GTAModding.com. This topic will attempt to fully document the file format. The file is a binary file and is split into seven distinct sections. Section 4 is mostly documented, controlling a variety of behaviors for camera control, police, and map visibility. I have generated a table of all values for sections 1 to 4 here.
-- SECTION 1 -- 0x00000 - dword - number of entries in section 2 -- SECTION 2 -- 0x00004 - 52 bytes - structures 0x00 - float - center 0x0C - float - x bottom left/top right 0x14 - float - y bottom left/top right 0x1C - float - z bottom left/top right 0x24 - dword - ? 0x28 - word - ? 0x2C - word - ? 0x2E - word - ? 0x30 - word - ? 0x32 - word - ? 0x34 - word - ? -- SECTION 3 -- 0x06804 - dword - number of entries in section 4 -- SECTION 4 -- 0x06808 - 28 bytes - structures 0x00 - float - x bottom left/top right 0x08 - float - y bottom left/top right 0x10 - float - z bottom left/top right 0x18 - word - flag, see below for details 0x1A - word - flag, unknown details -- SECTION 5 -- 0x08788 - ? -- SECTION 6 -- 0x23538 - ? -- SECTION 7 -- 0x26030 - ?I am stumped at how the last three sections are formatted. It looks like they are just a bunch of 2-byte values with no structure at all.
Map of section 2:
Map of section 4:
Flags for section 4:
|1||00000001||Both on foot using classic controls and in car, when you are in the zone in third person camera modes, the camera is stuck to a close in view. Once you leave the zone, the camera returns to its former distance. If the camera is already in cinematic or GTA 2 camera mode when you enter the zone, nothing changes. The camera mode can be changed to first person, but then afterwards changing camera modes remains stuck in third person. Once you leave the zone, it will automatically switch to cinematic mode.|
|2||00000010||When on foot, the camera is stuck in place as it remotely follows the player. The position where the camera is stuck seems to depend on the zone geometry and point of entry. The player is best controlled when in classic controls; the zone was not designed for standard controls. If you are in GTA 2 camera mode, it will leave that mode until you leave the zone. The flag has no effect on cars.|
|4||00000100||When in a vehicle, GTA 2 camera mode is disabled and becomes first person. When on foot, GTA 2 camera mode is just disabled. Once you leave the zone, the camera returns to normal.|
|8||00001000||Rubbish is limited on the ground and there are no raindrops when it is raining. The weather can still be rainy though, like dark skies, reflective ground, etc.|
|16||00010000||Cops in vehicles will ignore you but you can still attain wanted level as usual. They will not chase you or use their siren. Police cars still spawn as usual when you are wanted. Cops on foot seem to be stuck in a spot when spawned but sometimes they can move to a limited extent. They will still shoot at you like normal. Once you leave the zone, they will resume chasing you down.|
|64||01000000||Resumes level transitions when traveling under z = -4.0 (level transitions are disabled below that level).|
|128||10000000||An interior system like Vice City and onwards was implemented for GTA III's subway system and tunnels. They are by default invisible. When you are in the zone, they will become visible.|
Vice City doesn't seem to read the Cullzone.dat and Cullzoneempty.dat files. Sections 1 and 3 for the former, and sections 1, 2, and 3 for the latter are completely blank.