If you notice that your rooms don’t contain volume data and don’t respect the vertical boundaries when encountering “Room bounding elements”, make sure your Revit project is calculating volumes.

To activate this, go to Analyze > Space and Zones > Areas and Volume Computations

Ensure “Areas and Volumes” is selected.

You are now ready to audit your room volume boundaries in Revit and re-export the VIM file with the correct room volumes