According to this https://docs.unity3d.com/Manual/LevelOfDetail.html, if I name the mesh containing filename to be suffixed with _LOD0, _LOD1, etc it will auto create the LOD Group for them, however I'm not seeing this behaviour when I do. When the documentation says mesh file, does it actually mean the mesh and so all LODs have to be within a single fbx? Or can the LODs be in separate fbx files?