Problem: Lighmapping a complex model


I am fairly new to blender and just learning light mapping. I have made a model(fairly complex) where some meshes have more than one texture and multiple meshes share one texture… Some have textures which have been scaled to look tiled… I made this for unity game engine. So when I made each object I didnt assign it a material. I just unwrapped it around textures. It worked well. But obviously this doesnt work for making light maps… So according to some tutorials, I selected each object or faces which belong together and assigned it new materials and assigned new texture to them. this itself is driving me crazy cause like I said some meshes have more than one texture. But made materials for each of them and textured them… and created a new UV channel and made a new UV map, joined all the meshes and unwrapped them… and baked the light map and saved it. This method worked well with small scale models but for some reason doesnt work well/look good on my model when i load it in Unity and assign the lightmaps(which has to spheres each with 2 textures and and a bridge, which has multiple textures between them)… I am so tired of trying out different things… Please give me some advice… Thank you!

This is how it looks like it Unity. I have only done the lightmapping to the bridge… and each part of the bridge has its own material… but some of these materials share the same texture, like the rail and the bottom have two diff materials but share the same texture(same image)… I have two bright lights to see if its working… But I can tell its not cause I do not see proper shadows…

And this is how it looks like in blender…

Plus also some parts do this

…when it should look like this: