Thx murphy, I read that awhile ago
but I think you misunderstood me of the problem I have, my map is simply pitch black dark. It has lantern (with dynamic light) you could pick it up and wonder around with it in this map.
Here is example of what I'm talking about:
BSP vs Staticmesh - YouTube
These are 2 boxes one of them is BSP and other is static, you can notice the lighting on them from my lantern.
The BSP one's lighting is simple, lighting up all around but it's smooth with floor as you can see. The Staticmesh has dark sides and doesn't match with the floor, It's not big deal with box staticmesh but some other ones with complicated shapes is.