#### IfcPropertyBoundedValue

Natural language names

##### Semantic definitions at the entity

Entity definition

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:

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

Attribute definitions

# | Attribute | Type | Cardinality | Description
--- | --- | --- | --- | ---
3 | UpperBoundValue | - |  | This attribute is out of scope for this model view definition and shall not be set.
4 | LowerBoundValue | - |  | This attribute is out of scope for this model view definition and shall not be set.
5 | Unit | - |  | This attribute is out of scope for this model view definition and shall not be set.

Formal Propositions

Rule | Description
--- | ---
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.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description
--- | --- | --- | --- | ---
IfcProperty
1 | Name | IfcIdentifier | [1:1] | Name for this property. This label is the significant name string that defines the semantic meaning for the property.
2 | Description | - |  | This attribute is out of scope for this model view definition and shall not be set.
IfcSimpleProperty
IfcPropertyBoundedValue
3 | UpperBoundValue | - |  | This attribute is out of scope for this model view definition and shall not be set.
4 | LowerBoundValue | - |  | This attribute is out of scope for this model view definition and shall not be set.
5 | Unit | - |  | This attribute is out of scope for this model view definition and shall not be set.

##### Formal representations

XSD Specification
`<xs:element name="IfcPropertyBoundedValue" type="ifc:IfcPropertyBoundedValue" substitutionGroup="ifc:IfcSimpleProperty" nillable="true"/>
<xs:complexType name="IfcPropertyBoundedValue">
<xs:complexContent>
<xs:extension base="ifc:IfcSimpleProperty"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`*)
ENTITY IfcPropertyBoundedValue
SUBTYPE OF (IfcSimpleProperty);
UpperBoundValue : OPTIONAL IfcStrippedOptional;
LowerBoundValue : OPTIONAL IfcStrippedOptional;
Unit : OPTIONAL IfcStrippedOptional;
WHERE
WR21 : NOT(EXISTS(UpperBoundValue)) OR NOT(EXISTS(LowerBoundValue)) OR (TYPEOF(UpperBoundValue) = TYPEOF(LowerBoundValue));
WR22 : EXISTS(UpperBoundValue) OR EXISTS(LowerBoundValue);
END_ENTITY;
(*

EXPRESS-G diagram

`

Inheritance Graph:

ENTITY IfcPropertyBoundedValue
ENTITY IfcProperty
Name : IfcIdentifier;
Description : OPTIONAL IfcStrippedOptional;
INVERSE
ENTITY IfcSimpleProperty
ENTITY IfcPropertyBoundedValue
UpperBoundValue : OPTIONAL IfcStrippedOptional;
LowerBoundValue : OPTIONAL IfcStrippedOptional;
Unit : OPTIONAL IfcStrippedOptional;
END_ENTITY;

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