Skyrim has a dedicated tree LOD system, which uses a tree LOD texture atlas (build from tree LOD billboards) and specific data files (not true NIF meshes like terrain LOD or object LOD) to show tree LOD in the game.
While this is commonly referred to as tree LOD, it might also be referred to as standard tree LOD or traditional tree LOD when trying to distinguish between similar tree LOD with tree LOD billboards done in object LOD, e.g. ultra tree LOD.
Each tree has one tree LOD billboard texture, typically the front view of the model.
The tree LOD billboard texture is shown on 2 double sided planes intersecting each other at a 90 degree angle.
The tree LOD system does not use normal map textures and thus has limited lighting.
The tree LOD system can only show straight up-right trees.
Tree LOD is generated if a tree LOD billboard is found for a tree in the load order. In this context trees are references that use base records of the types 'TREE' and 'STAT' with the 'Has Tree LOD' flag set.
fTreeLoadDistance=distance for tree LOD in game units
Tree LOD data files:
Tree LOD atlas textures:
- No normal map textures resulting in limited lighting.
- No x or y rotation angles, always pointing straight up.
- Fixed billboard center, so there can be a lot of transparency overdraw because diffuse textures can not be trimmed.
- One billboard side per tree.
- One tree LOD atlas texture per worldspace.
- Maximum of 256 billboards per tree LOD atlas texture/worldspace.
- Tree LOD only unloads correctly if the load order of plugins adding tree references does not change after tree LOD generation.
- Tree LOD in parent worldspace used for LOD does not unload in child worldspaces.
- Tree LOD does not unload for references added by ESL flagged plugins.
- FPS problems in Skyrim when 3rd person camera crosses cell borders.
- FPS problems in Skyrim Special Edition or Skyrim Anniversary Edition when many plugins are installed - can be fixed by SSE Engine Fixes.