Unable to Create Rooms

[Anonymous]

Situation:

Several spaces have been created with a floor at 1000mm above LEVEL 2 (4000mm).  The walls for these spaces have the same base offset 1000mm above LEVEL 2).  When LEVEL 2 floor plan is open, Revit will not allow me to create those rooms.  If I make a new level at 6000mm, I have no issues creating the rooms.  Is there a way I can create those rooms without adding a new level for constraint?

[L.Maas]

Yes, it is possible. In a section or elevation view. Select the level and adjust the computational height accordingly (default at 0).

Note that this is a setting for the whole level. So it might impact other rooms on the level (imagine rooms with slanted walls)