IfcRelConnectsElements

BACnet MVD

#### IfcRelConnectsElements

Natural language names

| Verbindet Elemente - Relation
| Rel Connects Elements
| Connection d'éléments

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcRelConnectsElements |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.

##### Semantic definitions at the entity

Entity definition

The IfcRelConnectsElements objectified relationship provides the generalization of the connectivity between elements. It is a 1 to 1 relationship. The concept of two elements being physically or logically connected is described independently from the connecting elements. The connectivity may be related to the shape representation of the connected entities by providing a connection geometry.

- In this case the geometrical constraints of the connection are provided by the optional relationship to the IfcConnectionGeometry. The connection geometry is provided as a point, curve or surface within the local placement coordinate systems of the connecting elements.
- If the connection geometry is omitted then the connection is provided as a logical connection. Under this circumstance, the connection point, curve or surface has to be recalculated by the receiving application.

> HISTORY New entity in IFC1.0.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
5 | ConnectionGeometry | IfcConnectionGeometry | ? | The geometric shape representation of the connection geometry that is provided in the object coordinate system of the RelatingElement (mandatory) and in the object coordinate system of the RelatedElement (optionally). | X | X
6 | RelatingElement | IfcElement |  | Reference to a subtype of IfcElement that is connected by the connection relationship in the role of RelatingElement. | X | X
7 | RelatedElement | IfcElement |  | Reference to a subtype of IfcElement that is connected by the connection relationship in the role of RelatedElement. | X | X

Formal Propositions

Rule | Description
--- | ---
NoSelfReference | The instance of the RelatingElement shall not be the same instance as the RelatedElement.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId |  | Assignment of a globally unique identifier within the entire software world. | X | 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

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 | X
4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. |  | X
IfcRelationship
IfcRelConnects
IfcRelConnectsElements
5 | ConnectionGeometry | IfcConnectionGeometry | ? | The geometric shape representation of the connection geometry that is provided in the object coordinate system of the RelatingElement (mandatory) and in the object coordinate system of the RelatedElement (optionally). | X | X
6 | RelatingElement | IfcElement |  | Reference to a subtype of IfcElement that is connected by the connection relationship in the role of RelatingElement. | X | X
7 | RelatedElement | IfcElement |  | Reference to a subtype of IfcElement that is connected by the connection relationship in the role of RelatedElement. | X | X

##### Definitions applying to Design Transfer View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Definitions applying to BACnet View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Formal representations

XML Specification
`<xs:element name="IfcRelConnectsElements" type="ifc:IfcRelConnectsElements" substitutionGroup="ifc:IfcRelConnects" nillable="true"/>
<xs:complexType name="IfcRelConnectsElements">
<xs:complexContent>
<xs:extension base="ifc:IfcRelConnects">
<xs:sequence>
<xs:element name="ConnectionGeometry" type="ifc:IfcConnectionGeometry" nillable="true" minOccurs="0"/>
<xs:element name="RelatingElement" type="ifc:IfcElement" nillable="true"/>
<xs:element name="RelatedElement" type="ifc:IfcElement" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcRelConnectsElements
SUPERTYPE OF(ONEOF(IfcRelConnectsPathElements, IfcRelConnectsWithRealizingElements))
SUBTYPE OF (IfcRelConnects);
ConnectionGeometry : OPTIONAL IfcConnectionGeometry;
RelatingElement : IfcElement;
RelatedElement : IfcElement;
WHERE
NoSelfReference : RelatingElement :<>: RelatedElement;
END_ENTITY;

EXPRESS-G diagram

`

References: IfcElement

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