Here is solution for exporting multiple LOD objects in one FBX for Unreal Engine 4. It requires some fbx script modification which you can see at the end of the video.
Source
![UPBGE – [ C13/30] Creating planetary space exploration (Alien Creation / @joyack3d )](https://i.ytimg.com/vi/b-SjkfNZE3g/hqdefault.jpg)
![UPBGE – [ C12/30] Creating planetary space exploration (Alien Creation / @joyack3d )](https://i.ytimg.com/vi/3NFBNIPNiiM/hqdefault.jpg)
Blender UE4 LOD Export in One FBX File