IFC 4.3.x development IfcConversionBasedUnitWithOffset

Change log


added Semantic definitions at the entity

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:


    IfcDimensionalExponents(0, 0, 0, 0, 1, 0, 0),

``` Attributes

# Attribute Type Description
1 Dimensions IfcDimensionalExponents The dimensional exponents of the SI base units by which the named unit is defined.
2 UnitType IfcUnitEnum The type of the unit.
3 Name IfcLabel The word, or group of words, by which the conversion based unit is referred to.
4 ConversionFactor IfcMeasureWithUnit The physical quantity from which the converted unit is derived.
HasExternalReferenceSET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjectsReference to external information, e.g. library, classification, or document information, which is associated with the conversion-based unit.

> IFC4 CHANGE New inverse attribute.
5 ConversionOffset IfcReal A positive or negative offset to add after the inherited ConversionFactor was applied. Entity inheritance

dot_inheritance IfcConversionBasedUnitWithOffset IfcConversionBasedUnitWithOffset IfcConversionBasedUnit IfcConversionBasedUnit IfcConversionBasedUnitWithOffset->IfcConversionBasedUnit IfcNamedUnit IfcNamedUnit IfcConversionBasedUnit->IfcNamedUnit IfcContextDependentUnit IfcContextDependentUnit IfcContextDependentUnit->IfcNamedUnit IfcSIUnit IfcSIUnit IfcSIUnit->IfcNamedUnit Formal representations

ENTITY IfcConversionBasedUnitWithOffset
 SUBTYPE OF (IfcConversionBasedUnit);
	ConversionOffset : IfcReal;