IfcPropertyBoundedValue

Definition from IAI: A property with a bounded value (IfcPropertyBoundedValue) defines a property object which has a maximum of two (numeric or descriptive) values assigned, the first value specifying the upper bound and the second value specifying the lower bound. It defines a property - value bound (min-max) combination for which the property name, the upper bound value with measure type, the lower bound value with measure type (and optional the unit) is given.

The unit is handled by the Unit attribute:

If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext).
If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit.

The IfcPropertyBoundedValue allows for the specification of an interval for the value component of the property description. If either the LowerBoundValue or the UpperBoundValue is not given, then it indicates an open bound (either a minimum value or a maximum value). The interval is by definition inclusive, i.e. the value given for the LowerBoundValue or the UpperBoundValue is included in the interval.

Examples of a property with bounded value are:

Name	UpperBoundValue	LowerBoundValue	Type (through IfcValue, WR1 ensures same type for both values)	Unit
OverallHeight	1930	2300	IfcPositiveLengthMeasure	-
OverallWidth	0.9	1.25	IfcPositiveLengthMeasure	m
MaxHeight	20.0	<nil>	IfcPositiveLengthMeasure	-
MinWeight	<nil>	20	IfcMassMeasure	kg

HISTORY: New entity in IFC Release 2x.

IFC2x PLATFORM CHANGE: The attribute type of the attribute UpperBoundValue and LowerBoundValue has been changed from mandatory to optional with upward compatibility for file based exchange.

Informal proposition:

If the measure type for the upper and lover bound value is a numeric measure, then the following shall be true: UpperBoundValue > LowerBoundValue.

EXPRESS specification:

ENTITY IfcPropertyBoundedValue

SUBTYPE OF (

IfcSimpleProperty);

UpperBoundValue

OPTIONAL IfcValue;

LowerBoundValue

OPTIONAL IfcValue;

Unit

OPTIONAL IfcUnit;

WHERE

WR21	:	NOT(EXISTS(UpperBoundValue)) OR NOT(EXISTS(LowerBoundValue)) OR (TYPEOF(UpperBoundValue) = TYPEOF(LowerBoundValue));
WR22	:	EXISTS(UpperBoundValue) OR EXISTS(LowerBoundValue);

END_ENTITY;

Attribute definitions:

UpperBoundValue	:	Upper bound value for the interval defining the property value. If the value is not given, it indicates an open bound (all values to be greater than or equal to LowerBoundValue).
LowerBoundValue	:	Lower bound value for the interval defining the property value. If the value is not given, it indicates an open bound (all values to be lower than or equal to UpperBoundValue).
Unit	:	Unit for the upper and lower bound values, if not given, the default value for the measure type (given by the TYPE of the upper and lower bound values) is used as defined by the global unit assignment at IfcProject.

Formal Propositions:

WR21	:	The measure type of the upper bound value shall be the same as the measure type of the lower bound value, if both (upper and lower bound) are given.
WR22	:	Either the upper bound, or the lower bound, or both bounds shall be given.

Inheritance graph

ENTITY IfcPropertyBoundedValue;

ENTITY IfcProperty;

Name

IfcIdentifier;

Description

OPTIONAL IfcText;

INVERSE

PropertyForDependance

SET OF IfcPropertyDependencyRelationship FOR DependingProperty;

PropertyDependsOn

SET OF IfcPropertyDependencyRelationship FOR DependantProperty;

PartOfComplex

SET [0:1] OF IfcComplexProperty FOR HasProperties;

ENTITY IfcSimpleProperty;

ENTITY IfcPropertyBoundedValue;

UpperBoundValue

OPTIONAL IfcValue;

LowerBoundValue

OPTIONAL IfcValue;

Unit

OPTIONAL IfcUnit;

END_ENTITY;