IfcConversionBasedUnitWithOffset

Item	SPF	XML	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcConversionBasedUnitWithOffset			ADDED

Semantic definitions at the entity

Entity definition

IfcConversionBasedUnitWithOffset is a unit which is converted from another unit by applying a conversion factor and an offset.

HISTORY New entity in IFC4.

Example: The temperature unit Fahrenheit is based on the temperature unit Kelvin as follows:

f = k · 1.8 – 459.67

wherein k is an absolute temperature expressed in Kelvin and f is the same temperature in Fahrenheit. The following entity instances provide Fahrenheit as a unit:

IfcConversionBasedUnitWithOffset(

    IfcDimensionalExponents(0, 0, 0, 0, 1, 0, 0),
    THERMODYNAMICTEMPERATUREUNIT,
    'Fahrenheit',
    IfcMeasureWithUnit(
        IfcThermodynamicTemperatureMeasure(1.8),
        IfcSIUnit(THERMODYNAMICTEMPERATUREUNIT, ?, KELVIN)),
    -459.67);

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
5	ConversionOffset	IfcReal		A positive or negative offset to add after the inherited ConversionFactor was applied.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcNamedUnit
1	Dimensions	IfcDimensionalExponents		The dimensional exponents of the SI base units by which the named unit is defined.	X
2	UnitType	IfcUnitEnum		The type of the unit.	X
IfcConversionBasedUnit
3	Name	IfcLabel		The word, or group of words, by which the conversion based unit is referred to.	X
4	ConversionFactor	IfcMeasureWithUnit		The physical quantity from which the converted unit is derived.	X
	HasExternalReference	IfcExternalReferenceRelationship @RelatedResourceObjects	S[0:?]	Reference to external information, e.g. library, classification, or document information, which is associated with the conversion-based unit. IFC4 CHANGE New inverse attribute.	X
IfcConversionBasedUnitWithOffset
5	ConversionOffset	IfcReal		A positive or negative offset to add after the inherited ConversionFactor was applied.	X

Formal representations

XML Specification

 <xs:element name="IfcConversionBasedUnitWithOffset" type="ifc:IfcConversionBasedUnitWithOffset" substitutionGroup="ifc:IfcConversionBasedUnit" nillable="true"/>

 <xs:complexType name="IfcConversionBasedUnitWithOffset">

  <xs:complexContent>

   <xs:extension base="ifc:IfcConversionBasedUnit">

    <xs:attribute name="ConversionOffset" type="ifc:IfcReal" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcConversionBasedUnitWithOffset

 SUBTYPE OF (IfcConversionBasedUnit);

  ConversionOffset : IfcReal;

END_ENTITY;

 EXPRESS-G diagram

	Auf Umrechnung basierte Einheit mit Abzug
	Conversion Based Unit With Offset
	Unité basée sur une mesure avec unité et avec décalage