Trees LOD - images of trees in the distance, contained in files FNVLODGen generates objects LOD files from separate small lod meshes for each static object in game that have them, they have the same name and location as the full detail model with _lod.nif suffix. Objects LOD - any static object: houses, shacks, rocks, cliffs, etc contained in filesīoth terrain and objects LOD files are actually large nif macromeshes that can be opened with NifScope. Terrain LOD files are generated by GECK, FNVLODGen doesn't create them. Those files are rarely updated since mods almost never change terrain shape or changes are minimal and would be hardly noticable when far away. Terrain (landscape) LOD - the shape of landscape in the distance, contained in files FNVLODGen tries to address this issue by providing a simple one-click automated LOD files generation for the current load order of user, taking in account all mods that have content visible from distance.
Those LOD files are generated with GECK which is quite complex procedure unaccessible by majority of users. Some mods include updated LOD files to address this issue, but they are rare and usually incompatible with each other and require compatibility patches of their own. Fallout uses static LOD which means that LOD information is prebuilt and doesn't change when mods modify objects in game. LOD in general is what you see in the distance, beyond the uGridsToLoad setting value.
LOD mods highly recommended to install before generation which fix, improve and add new LOD models and textures
Once LOD generation has completed copy/move files from the dedicated output directory to the game data directory or into a custom mod (recommended for load order management) in MO. Add a dedicated output directory by adding -o:"C:\FNVLODGenOutput" to the "Arguments" field. Add FNVLODGen.exe to MO executable list by clicking the gears button and then browse for FNVLODGen.exe to fill the "Binary" field. Mod organizer users: Install FNVLODGen in a directory of your choice. When finished, close the program manually. Wait for it to complete, you can watch progress and check possible errors in messages list. Run FNVLODGen.exe, wait for it to load your plugins, then select worldspaces to generate LOD (by default only WastelandNV worldspace is selected, right click in the list to select all/none), and click Generate. Install FNVLODGen resource pack using your mod manager. Make sure to install FNVLODGen outside of Program files folder, somewhere with write access rights, or run as Administrator. Trees LOD generation is also available, though not recommended to use (read technical description down below) This tool allows to generate Objects LOD for worldspace(s) by scanning all mods in load order that add visible from distant objects.
Objects LOD generator for Fallout: New Vegas