As we mentioned before, the first floor of most buildings is most of the time different, so today you learn how to manipulate a specific floor, merge primitives and a few other tricks to customize how to place our modules.
This techniques can be applied to any part of the building, for example to add different areas that have different windows or doors and manipulate that area specifically.
This is a very important chapter cause it gives you a lot of tools to customize any area of your procedural models.