IFC Property Set Mistakes

Diagnose and fix the six recurring mistakes in IFC property sets, quantity sets and material associations : a reserved-prefix name collision, a property set attached to a type through the wrong relationship, a material-usage entity on a type, a hand-written derived attribute, a quantity carrying the wrong unit type, and the legacy IfcMaterialList in a modern file.

Two of these are schema-valid but wrong (a "smell") ; three break a WHERE rule (a hard error) ; one is a derived-attribute violation. ALWAYS classify the mistake before fixing it.

For the property and quantity entity model see ifc-syntax-property-sets. For the material entity model see ifc-syntax-materials. For units see ifc-syntax-units. For schema-validation mechanics see ifc-errors-schema-validation.

Quick Reference