IFC Entity Hierarchy

The IFC schema is a deep single-inheritance tree. Every meaningful object, relationship, and property definition descends from one abstract root, IfcRoot. This skill covers the identity backbone, the object inheritance chain down to concrete construction elements, the type versus occurrence model, and the IFC GUID. Verified against the IFC 4.3.2 specification (ISO 16739-1:2024) with IFC4 and IFC2x3 deltas noted inline.

Applies to IFC2x3, IFC4, IFC4.3. Read the version annotations: one hard file-breaking rename (IfcBuildingElement to IfcBuiltElement) sits inside this hierarchy.

Quick Reference

IfcRoot: the identity backbone