5 Core data schemas
The core data schemas establish the most general layer within the IFC schema architecture as shown highlighted in blue. Entities defined in this layer can be referenced and specialized by all entities above in the hierarchy. The core layer provides the basic structure, the fundamental relationships and the common concepts for all further specializations in aspect specific models.
All entities defined in the core layer and above derive from IfcRoot, having unique identification, name, description, and change control information.