How can I now, get back to the "normal" (3d of the whole model) mode?
Because even though I removed my marquee tool from the floor plan, I am still getting the same 3d as it was when the marquee tool was active.
you can also just go with F5 (standard to "show selection/marquee in 3d window"), and since you no longer have a marquee, it'll show you everything again.