It is best practice when creating a BIM model for export via gbXML/IFC (See section 12: File Types for more information) to develop the model geometry in a particular order.
1.Start with the external shell boundary wall
2.Add in the floor Levels/Ceiling Voids/Roofs
3.Then add in core areas
4.From there add in all other internal partitions
5.Finally incorporate any openings as required
At each stage test the model to check that the boundaries are fully enclosed by placing a room or space volume into the model (see rooms & spaces section for further information). You can even export the model to test it at this point as shown in the images below. When developing the model it is best practice to have only a single external boundary wall type, a single internal type partition if possible and a single floor slab/ceiling/roof type set with ‘Room Bounding’ ticked on. Please refer to section ‘Element properties’ for more information.
