Well, on a model I made of the restaurant fo my University, I placed the lights on the same place that the restaurant have it and looks good, placing the lights is a kind of a manual thing so, I was thinking on placing objects on the 3d desing of the map with certain names, so when loading the 3ds file if I found that object3D then just keeping the position to place a light there and dont add that object to the world, like identifiers.