LOD

LOD models are the low level of detail versions of the original models. This is what you see loaded far away. As you get closer to the LOD model, it should change to the original model if it has one.

How to

To create an LOD version of the original model, create a model that has a lower level of detail than the original model, i.e. less polygons and smaller textures.

In the IDE file, the draw distance of the LOD object should be 301-3000 units. The draw distance of the original object should be 300 units or less.

Vice City

The LOD models should have the same name as the original model, except the first three letters of the LOD model are replaced by the letters "LOD." Create an LOD version of the collision model of the original model. The LOD collision should be the same size as the original model's but with nothing in it.

San Andreas & GTA IV

In San Andreas and GTA IV LODs are linked within an indexing system. Basicly each line (or entry for binary file formats like binary IPLs or WPL/XPL) gets an index starting with 0 which represents the first line and increasing by one with each entry. The LOD index value for an non-LOD object defines the instance entry/line of an object which should be used as LOD object. To prevent display glitches make sure that the objects or at least their pivots of both (LOD and normal model) are placed near to each other.(example for GTA-IV: 69 would indicate that the lod model is placed on the map at line 69)

External Link

•  GTAForums: Explanation of GTA SA LOD System - Post by steve-m explaining the LOD system for IPL files in GTA SA.