Working in 3D can be e real challenge at times when you are used to only worrying about 2 dimensions. One tool I have found to be very handy is the ability to orient a 3D view of a multiple story building to show just one floor at a time.
To do this go to the View menu and select Orient and then To Other View.This will bring up a dialog that allows you to select the floor you want to view.
After you pick the floor, it will look like you have a plan view. Orbit your model to reveal your single 3D floor for coordination.