Elements may have a simplified 'Box' representation describing the dimensions of the smallest box bounding the object. Such representation may be used for more efficient spatial indexing or hit-testing.
The representation identifier and type and the only allowed single representation item of the 'Box' representation are:
NOTE The specification does not determine the method by which the bounding box has to be created. If such a method need to be prescribed the definition has to be established by model view definitions or implementer agreements.
Figure 66 illustrates an instance diagram.
Figure 66 — Box Geometry |
<?xml version="1.0"?>
<ConceptTemplate xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="b942ceb1-b818-4683-871b-9c979fa34dd5" name="Box Geometry" status="sample" applicableSchema="IFC4" applicableEntity="IfcProduct">
<Rules>
<AttributeRule AttributeName="Representation">
<EntityRules>
<EntityRule EntityName="IfcProductDefinitionShape">
<AttributeRules>
<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] = 'Box'" />
</Constraints>
</EntityRule>
</EntityRules>
</AttributeRule>
<AttributeRule RuleID="Type" AttributeName="RepresentationType">
<EntityRules>
<EntityRule EntityName="IfcLabel">
<Constraints>
<Constraint Expression="Type[Value] = 'BoundingBox'" />
</Constraints>
</EntityRule>
</EntityRules>
</AttributeRule>
<AttributeRule AttributeName="Items">
<EntityRules>
<EntityRule EntityName="IfcBoundingBox" />
</EntityRules>
</AttributeRule>
</AttributeRules>
</EntityRule>
</EntityRules>
</AttributeRule>
<AttributeRule AttributeName="Name" />
<AttributeRule AttributeName="Description" />
</AttributeRules>
</EntityRule>
</EntityRules>
</AttributeRule>
</Rules>
</ConceptTemplate>