IFC Attributes are the main identifiers of IFC Entities. The names of IFC Attributes are fixed, having been defined by buildingSMART as part of the IFC 2x3 scheme.
In the case of ArchiCAD, most of these IFC Attribute names are derived from the project. For example, the IFC Attributes of an IfcWall building element:
•GlobalId: the Globally Unique Identifier of the IfcWall in the IFC model.
•OwnerHistory: the assignment of the information about the current ownership of the IfcWall.
•Name: its derived value is the same as IfcWall’s ArchiCAD ID.
•Description: an optional textual description with a unique value.
•ObjectType: an optional label-type ID with custom value.
•Tag: a label identifier with value derived by default from and equal to the IfcWall’s ArchiCAD GUID (not equal to IFC GlobalId), but can be edited manually with custom text.
Note: In order to provide fast access, OwnerHistory is directly attached to all independent objects, relationships and properties. Its components and values are derived from project data and hidden in the ArchiCAD user interface. It includes for example the owning actor (OwningUser) of which multiple values are derived from the Person and Organization data.
See IFC Options.