IFC Syntax : Units

An IFC model declares its units once, at the project level, and every measure value rides on that declaration. This skill covers the unit entities, how they are assembled, and how a property value resolves to a concrete unit.

Applies to IFC2x3, IFC4, and IFC4.3. One entity changed type across versions : see the Version Differences section.

Quick Reference

The project unit assignment

IfcUnitAssignment is the project-global unit set. Verified verbatim (IFC4.3) :