The CULLZONE.DAT file consists of seven distinct sections. Many of the zones closely mimic the cull.ipl file, which does not seem to be used by the game. Ignoring rounding errors, all but one section 4 zone matches all zones with nonzero flags in the cull.ipl file. The only zone that differs is at the Shoreside Vale subway station.
Offset
Type
Description
Section 1: Number of cull zones
0x00000
dword
number of entries in section 2
Section 2: Zones
0x00004
52 bytes[512]
structures (see below)
Offset
Type
Description
0x00
float
x center
0x04
float
y center
0x08
float
z center
0x0C
float
x bottom left
0x10
float
x top right
0x14
float
y bottom left
0x18
float
y top right
0x1C
float
z bottom left
0x20
float
z top right
0x24
dword
?
0x28
word
?
0x2C
word
?
0x2E
word
?
0x30
word
?
0x32
word
?
0x34
word
?
Section 3: Number of attribute zones
0x06804
dword
number of entries in section 4
Section 4: Attribute zones
0x06808
28 bytes[288]
variety of behaviors for camera control, police, and map visibility (see below for structure)
Section 6: Pointers to big buildings for buildings
0x26030
?
Section 7: Pointers to big buildings for treadables
Attributes
Flag
Binary
Description
1
0000 0001
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
0000 0010
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
0000 0100
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
0000 1000
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
0001 0000
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.
32
0010 0000
64
0100 0000
When traveling under z = -4.0, by default all level transitions are disabled. Entering the zone resumes any level transitions. This flag is redundant on zones above that height as level transitions are also resumed when you travel above that height.
128
1000 0000
An interior system like GTA 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.
GTA Vice City
In addition to Cullzone.dat, GTA Vice City has a file called Cullzoneempty.dat. Both of these files are not used by the game at all. The game uses the cull.ipl file instead.