I have recently been working on a new game. I want to add a free roam mode to the game where the player moves about a city. However, when I import my (quite large) city model, I have major problems with lighting. Despite adding various types of lights and moving them around the city, the model remains quite dark.
You would probably be better off lighting your model in the 3D package that you created it with and then baking light maps. Since the buildings will never move and the lighting is going to stay the same throughout the level, I presume?