In case you need an explanation;
Level of Detail (LOD) models are displayed at varying distances; each LOd has decreasing polycounts and map sizes; i.e. lod0 may have 1000 polys and a 1024*1024 map, and LOD1 500 and a 256*256 map, etc.
What this means, is that as the model gets further away from the player, the LOD - the model displayed - is changed. This is to improve performance; the game thus doesn't need to store and draw all the details of the top LOD when the model is too far away to see them.
(A secondary thing is that moving down the gfx sliders will decrease the LOD distace / LODs drawn).
