With the necessary files now installed, open Revit.
In the Room & Area section select the drop-down box.
Click “Area and Volume Computations”.
In this window tick the “Areas and Volumes” option.
Click “Ok”.
Note: Elements will only be assigned to a room when the room boundary meets the surface of Walls, Floors, and Ceilings i.e. it will not assign Elements that the Room Boundary protrudes through.