IfcRelProjectsElement

Item	XML	Change	Description
IFC2x3 to IFC4
IfcRelProjectsElement
OwnerHistory		MODIFIED	Instantiation changed to OPTIONAL.
IFC4 Addendum 2
IfcRelProjectsElement
RelatingElement	X	MODIFIED	Xsdformat changed from Attribute to Hidden.

Semantic definitions at the entity

Entity definition

The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. The relationship is defined to be a 1:1 relationship, if an element has more than one projection, several relationship objects have to be used, each pointing to a different projection element. The IfcRelProjectsElement establishes an aggregation relationship between the main element and a sub ordinary addition feature.

NOTE In contrary the IfcRelAggregates relationship established an aggregation of equal parts to a whole.

The IfcRelProjectsElement implies a Boolean operation of addition for the geometric bodies of the element and the feature element. As with all decomposition relationships it determines:

existence dependency - the RelatedFeatureElement cannot exist without the RelatingElement
hierarchical and non-cyclical relationship - the IfcRelProjectsElement can only alter a single IfcElement
no spatial containment - the IfcFeatureElementAddition as related element never participates in the hiearchical spatial containment relationship IfcRelContainedInSpatialStructure

HISTORY New entity in IFC2x2.

IFC4 CHANGE Supertype changed to IfcRelDecomposes.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
5	RelatingElement	IfcElement		Element at which a projection is created by the associated IfcProjectionElement.	X
6	RelatedFeatureElement	IfcFeatureElementAddition		Reference to the IfcFeatureElementAddition that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRoot
1	GlobalId	IfcGloballyUniqueId		Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	?	Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE only the last modification in stored - either as addition, deletion or modification. IFC4 CHANGE The attribute has been changed to be OPTIONAL.	X
3	Name	IfcLabel	?	Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.	X
4	Description	IfcText	?	Optional description, provided for exchanging informative comments.	X
IfcRelationship
IfcRelDecomposes
IfcRelProjectsElement
5	RelatingElement	IfcElement		Element at which a projection is created by the associated IfcProjectionElement.	X
6	RelatedFeatureElement	IfcFeatureElementAddition		Reference to the IfcFeatureElementAddition that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element.	X

#	Concept	Template	Model View
IfcRoot
	Identity	Software Identity	General Usage
	Revision Control	Revision Control	General Usage

Formal representations

XML Specification

 <xs:element name="IfcRelProjectsElement" type="ifc:IfcRelProjectsElement" substitutionGroup="ifc:IfcRelDecomposes" nillable="true"/>

 <xs:complexType name="IfcRelProjectsElement">

  <xs:complexContent>

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

    <xs:sequence>

     <xs:element name="RelatedFeatureElement" type="ifc:IfcFeatureElementAddition" nillable="true"/>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcRelProjectsElement

 SUBTYPE OF (IfcRelDecomposes);

  RelatingElement : IfcElement;

  RelatedFeatureElement : IfcFeatureElementAddition;

END_ENTITY;

 EXPRESS-G diagram

	Hinzufügen / Addition von Teil zu Element - Relation
	Rel Projects Element

IfcRelProjectsElement

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to General Usage

Formal representations