IfcVertexLoop

BACnet MVD

#### IfcVertexLoop

Natural language names

| Vertexschleife - Topologie
| Vertex Loop
| Boucle de points

##### Semantic definitions at the entity

Entity definition

> NOTE Definition according to ISO/CD 10303-42:1992
> A vertex_loop is a loop of zero genus consisting of a single vertex. A vertex can exist independently of a vertex loop. The topological data shall satisfy the following constraint:

> NOTE Entity adapted from vertex_loop defined in ISO 10303-42.

> HISTORY New entity in IFC2x2.

Informal Propositions:

1. A vertex loop has zero extent and dimensionality.
2. The vertex loop has genus 0.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | LoopVertex | IfcVertex |  | The vertex which defines the entire loop. |  | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRepresentationItem

LayerAssignment

IfcPresentationLayerAssignment
@AssignedItems

S[0:1]

Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

> IFC2x3 CHANGE The inverse attribute LayerAssignments has been added.

> IFC4 CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.

X

StyledByItem

IfcStyledItem
@Item

S[0:1]

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.

> IFC2x3 CHANGE The inverse attribute StyledByItem has been added.

X

X

IfcTopologicalRepresentationItem
IfcLoop
IfcVertexLoop
1 | LoopVertex | IfcVertex |  | The vertex which defines the entire loop. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcVertexLoop" type="ifc:IfcVertexLoop" substitutionGroup="ifc:IfcLoop" nillable="true"/>
<xs:complexType name="IfcVertexLoop">
<xs:complexContent>
<xs:extension base="ifc:IfcLoop">
<xs:sequence>
<xs:element name="LoopVertex" type="ifc:IfcVertex" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcVertexLoop
SUBTYPE OF (IfcLoop);
LoopVertex : IfcVertex;
END_ENTITY;

EXPRESS-G diagram

`

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