The IfcConstraintResource schema in the resource layer defines basic concepts for defining constraints related to any object in the IFC model derived from IfcObject.
Example:
If there is a building regulation requiring that the area of a certain type of rooms shall be at least 15
square meters, this constraint can be expressed by instance of IfcObjetive capturing qualitative
information (i.e. that the room shall be big enough), ObjectiveQualifier being set to CodeCompliance and
ConstraintGrade set to Hard (and the name of the building code can be given in ConstraintSource).
Quantitative information is captured by instance of IfcMetricBenchmark, (referenced by
IfcObjetive), where Benchmark is set to GreaterThanOrEqualTo and where the Values has one instance of
IfcMetricValue, with DataType Scalar and DataValue capturing the actual required area (15 square
meter).
HISTORY This is new schema in IFC 2x, containing
IfcConstraint and its subtypes, previously in IfcControlExtension.
