Figure 107 — Reference Geometry
A specific form of geometry representation is the 'Reference' geometry. It is used to provide a geometry used for various forms of assessments (like for quantities, etc.) but not for display and also not for implicit Boolean operations in a voiding relationship.
EXAMPLE An example is the use of 'Reference' representation is for opening elements that shall not be used to create a void using the IfcRelVoidsElement relationship, since the voids are already part of the 'Body' representation of the voided element. The representation identifier of the representation is:
- IfcShapeRepresentation.RepresentationIdentifier = 'Reference'
Figure 107 illustrates an instance diagram.
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Figure 107 — Reference Geometry |
<?xml version="1.0"?>
<ConceptTemplate xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="d68f9f1b-223a-4a8a-912b-b83f032a74f2" name="Reference Geometry" applicableSchema="IFC4" applicableEntity="IfcProduct">
<Rules>
<AttributeRule AttributeName="Representation">
<EntityRules>
<EntityRule EntityName="IfcProductDefinitionShape">
<AttributeRules>
<AttributeRule AttributeName="Name" />
<AttributeRule AttributeName="Description" />
<AttributeRule AttributeName="Representations">
<EntityRules>
<EntityRule EntityName="IfcShapeRepresentation">
<AttributeRules>
<AttributeRule AttributeName="ContextOfItems">
<EntityRules>
<EntityRule EntityName="IfcGeometricRepresentationContext" />
</EntityRules>
</AttributeRule>
<AttributeRule RuleID="Identifier" AttributeName="RepresentationIdentifier">
<EntityRules>
<EntityRule EntityName="IfcLabel">
<Constraints>
<Constraint Expression="Identifier[Value] = 'Reference'" />
</Constraints>
</EntityRule>
</EntityRules>
</AttributeRule>
<AttributeRule RuleID="Type" AttributeName="RepresentationType">
<EntityRules>
<EntityRule EntityName="IfcLabel" />
</EntityRules>
</AttributeRule>
</AttributeRules>
</EntityRule>
</EntityRules>
</AttributeRule>
</AttributeRules>
</EntityRule>
</EntityRules>
</AttributeRule>
</Rules>
</ConceptTemplate>
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