The storey a room or space belongs to is determined by the vertical location of the base of the room in Massing, or base of the flooring in BIM.
Typically rooms/ spaces that belong to a storey have their bases located on the base level of the storey.
Mezzanines, in multi-leveled layouts, have a vertical displacement from the storey base: They can be either above or below the storey base.
In any 3D view, simply Move a room up or down vertically to create a mezzanine.
You can also simply Move the bottom face of a mass up or down to create the mezzanine.
Mezzanines belong to the storey their bases are closest to vertically.
Up to a height equal to half the storey height, rooms belong in the same storey, i.e., If the storey height is 3000 mm, mezzanines that are upto 1500 mm above or below it belong to the same storey. Beyond this distance, the mezzanine belongs to the next storey, above or below.
On replicating, mezzanines and split level rooms are copied up exactly on top of themselves, like typical rooms.Did this answer your question?