Thanks for the reply Omnicypher! I Tried to unwrap UVs as you said, it would be great if you can inspect my blend file and tell if the light map is correct or not. And how can I make sure that my lightmapCoordinateIndex is one, Is that a setting in UE4 or blender? How can I set which UV Channel to Use for lightmap information? Also, Is blender the right program to UV unwrap things, or I should use some other program like 3ds max or C4D?? Here is the file.