LOD billboards are diffuse *.DDS textures that show the rendered 3D model from a front view and a *.TXT file with additional information about the width, height etc.
The LOD billboards are typically used for a simple 2 plane model crossing like an X if viewed from top.
LOD billboards work the same for any game version and can be interchanged as desired.
All LOD billboards files are in ..\Textures\Terrain\LODGen\*.*.
Automatically Create LOD Billboards
See the TexGen Configuration for more information, including how to force generation of LOD billboards that were not generated automatically.
3rd Party LOD Billboards
Do not install 3rd party LOD billboards. Use TexGen to generate them.
Generating all LOD billboards guaranties that they match the currently installed full models and textures.
While 3rd party LOD Billboards will still generally still work, they are visually inferior and in some cases cause warning messages.