Agreement on the minimum set of default units to be defined within the project context

Based on          IFC2x3

Initiator            Official buildinSMART IFC2x3 CV2.0 certification programme

Effects              Coordination View 2.0

Date                    2010 09


The following units need to be defined as a minimum at IfcProject.UnitsInContext.

    * length unit,

    * plane angle unit,

    * area unit,

    * volume unit.

Units can either be provided as SI units using IfcSIUnit, or as derived (imperial) units using IfcComversionBasedUnit. For IfcSiUnit's the Name attribute and Prefix attribute shall agree to the units shown below. For IfcConversionBasedUnit's the Name attribute shall only have one of the string values shown below.

The following units are supported:

    * length unit:

        - for metric units: m, mm, cm;

        - for imperial units: 'inch', 'foot'

    * area unit:

        - for metric units: m2, mm2, cm3;

        - for imperial units: 'square inch', 'square foot'

    * volume unit:

        - for metric units: m3, cm3, mm3;

        - for imperial units: 'cubic inch', 'cubic foot'

    * plane angle unit:

        - for metric units: radian; 'degree';

        - for imperial units: radian; 'degree'

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