In addition to the section regarding ‘Rooms and Spaces’, the volumes of ceiling voids also need to be considered. It is common these volumes are missed when exporting from the main Revit design model resulting in large gaps between floor levels within the energy models. This in turn will result in incorrect results when simulating your building.
A design team agreement should be reached at the outset of the project noting the responsibility of who will account for these and when they will be taken into account. For early stage analysis these could be omitted exporting the room volumes tied to floor to floor heights (NB: any ceiling elements should have room bounding unticked to achieve a clean gbXML in this manner – See Section 9 Utilising Floor Levels for more information).
For a more detailed stage analysis there are two options.
1.Export the ceiling voids included within the Revit gbXML model creating levels for the ceiling voids and tie the rooms or spaces to the correct levels.
Image from Autodesk Revit: using levels to set up room/space volumes for export – elevation view.
Or
2.The same floor to floor volumes are exported as at concept stage with the ceiling voids being added into the geometry to create them within the VE using the ‘ceiling voids’ tool, or other modelling tools within the ‘ModelIT’ applications.
If these volumes are to be exported from the Revit model, then a room/space must be placed for these like any other volume within your Revit model.
