OCCL (IPL section)| Short description: | Creates occlusion culling zones |
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| Supported games: |    |
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| IPL Sections:
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OCCL is a section in the item placement file in Vice City, San Andreas, and GTA IV. It is used to create occlusion culling zones that helps make the game run smoother in certain parts of the world. Since it is wasteful to render models behind opaque models, these zones can disable the rendering of any models that are directly behind the zones.
Format
Vice City
A map of Vice City's
occlu.ipl areas
occl
MidX, MidY, BottomZ, WidthX, WidthY, Height, Rotation
end
The section is used in the occlu.ipl file but it can be used in any IPL files.
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|
Identifier
|
Type
|
Description
|
| A,B |
MidX, MidY |
float[2] |
The X and Y coordinates of the center of the occlusion zone.
|
| C |
BottomZ |
float |
The bottom Z coordinate of the occlusion zone.
|
| D,E |
WidthX, WidthY |
float[2] |
The width of the occlusion zone in units.
|
| F |
Height |
float |
The height of the zone — the difference between the top and the bottom of the zone.
|
| G |
Rotation |
float |
The rotation of the occlusion zone in degrees.
|
San Andreas
The section is used in occluint.ipl, occluLA.ipl, occlusf.ipl, and occluveg.ipl files.
occl
MidX, MidY, BottomZ, WidthX, WidthY, Height, Rotation, , ,
end
|
|
Identifier
|
Type
|
Description
|
| A,B |
MidX, MidY |
float[2] |
The X and Y coordinates of the center of the occlusion zone.
|
| C |
BottomZ |
float |
The bottom Z coordinate of the occlusion zone.
|
| D,E |
WidthX, WidthY |
float[2] |
The width of the occlusion zone in units.
|
| F |
Height |
float |
The height of the zone — the difference between the top and the bottom of the zone.
|
| G |
Rotation |
float |
The rotation of the occlusion zone in degrees.
|
| H,I |
|
float |
|
| J |
|
int |
|
Issues
When removing buildings from the world, you may see unexpected pop ups caused by existing occlusion zones. Deleting all the occlusion zones is the easiest solution. An example of this issue is the Liberty City project. Before this section was researched, the team experienced unexpected pop ups with models loading and unloading behind areas where Vice City's buildings used to be. Someone realized that the occlu.ipl was the problem and deleted every line in that file. The pop ups disappeared and the issue was resolved.
Statistics
Total number of OCCL entries in:
- Vice City: 344 (max 350)
Tools and scripts
GTAForums: Script pack for 3ds Max – by Deniska
