IfcQuantityWeight

BACnet MVD

#### IfcQuantityWeight

Natural language names

| Mengenangabe - Gewicht
| Quantity Weight
| Quantité de poids

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcQuantityWeight |  |  |  |
Formula |  |  | ADDED |

##### Semantic definitions at the entity

Entity definition

IfcQuantityWeight is a physical element quantity that defines a derived weight measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.

> EXAMPLE The amount of reinforcement used within a building element may be measured according to its weight. The actual size of the weight depends on the method of measurement used.

> HISTORY New entity in IFC2x. It replaces the calcXxx attributes used in previous IFC Releases.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
4 | WeightValue | IfcMassMeasure |  | Mass measure value of this quantity. |  | X

5

Formula

IfcLabel

?

A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.

> IFC4 CHANGE Attribute added to the end of the attribute list.

X

Formal Propositions

Rule | Description
--- | ---
WR21 | If a unit is given, the unit type shall be mass unit. NOTE There is no distinction between the concept of "Mass" and "Weight" in the current IFC Release.
WR22 | A valid weight quantity shall be greater than or equal to zero.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcPhysicalQuantity
1 | Name | IfcLabel |  | Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements. |  | X
2 | Description | IfcText | ? | Further explanation that might be given to the quantity. |  | X

HasExternalReferences

IfcExternalReferenceRelationship
@RelatedResourceObjects

S[0:?]

Reference to an external reference, e.g. library, classification, or document information, that is associated to the quantity.

> IFC4 CHANGE New inverse attribute.

X

| PartOfComplex | IfcPhysicalComplexQuantity @HasQuantities | S[0:1] | Reference to a physical complex quantity in which the physical quantity may be contained. |  | X
IfcPhysicalSimpleQuantity
3 | Unit | IfcNamedUnit | ? | Optional assignment of a unit. If no unit is given, then the global unit assignment, as established at the IfcProject, applies to the quantity measures. |  | X
IfcQuantityWeight
4 | WeightValue | IfcMassMeasure |  | Mass measure value of this quantity. |  | X

5

Formula

IfcLabel

?

A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.

> IFC4 CHANGE Attribute added to the end of the attribute list.

X

##### Formal representations

XML Specification
`<xs:element name="IfcQuantityWeight" type="ifc:IfcQuantityWeight" substitutionGroup="ifc:IfcPhysicalSimpleQuantity" nillable="true"/>
<xs:complexType name="IfcQuantityWeight">
<xs:complexContent>
<xs:extension base="ifc:IfcPhysicalSimpleQuantity">
<xs:attribute name="WeightValue" type="ifc:IfcMassMeasure" use="optional"/>
<xs:attribute name="Formula" type="ifc:IfcLabel" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcQuantityWeight
SUBTYPE OF (IfcPhysicalSimpleQuantity);
WeightValue : IfcMassMeasure;
Formula : OPTIONAL IfcLabel;
WHERE
WR21 : NOT(EXISTS(SELF\IfcPhysicalSimpleQuantity.Unit)) OR
(SELF\IfcPhysicalSimpleQuantity.Unit.UnitType = IfcUnitEnum.MASSUNIT);
WR22 : WeightValue >= 0.;
END_ENTITY;

EXPRESS-G diagram

`

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