Here I am, back again. Again thanks for all the nice comments.
I was thinking of doing some bird view of the city and the swamp sea, but that would take some time… right now I have multiple sets but I don’t have a complete environment. We’ll see.
Yes zemmuonne I use groups. I know it sucks, I know I should use layers instead (and in other projects I use them a lot) but this one simply grew with goups by basically inheriting them from older scenes. There is one little trick tough, since the scene is divided in levels as said before, I completed the set pieces coming from the background till the foreground (which needed more details and more specific modeling). Once every set piece was done, I launched the rendering onto a second PC and continued working on the next level. In the end, when I finished modeling the foreground, all the previous layers where already rendered and therefore I had to wait restless only for the foreground to render before beginning compositing on photoshop.
Of course most of the objects were already done from previous scenes, (example)
and since I basically maintained the same conventions across the board (names, materials, dimensions) integrating alltogether was rather simple. As I said, lighting was a little more complicated, but it just required some planning.