IfcPath

BACnet MVD

#### IfcPath

Natural language names

| Pfad - Topologie
| Path
| Chemin

##### Semantic definitions at the entity

Entity definition

> NOTE Definition according to ISO/CD 10303-42:1992
> A path is a topological entity consisting of an ordered collection of oriented edges, such that the edge start vertex of each edge coincides with the edge end of its predecessor. The path is ordered from the edge start of the first oriented edge to the edge end of the last edge. The BOOLEAN value sense in the oriented edge indicates whether the edge direction agrees with the direction of the path (TRUE) or is the opposite direction (FALSE).
> An individual edge can only be referenced once by an individual path. An edge can be referenced by multiple paths. An edge can exist independently of a path.

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

> HISTORY New entity in IFC2.0

Informal Propositions:

1. A path has dimensionality 1.
2. A path is arcwise connected.
3. The edges of the path do not intersect except at common vertices.
4. A path has a finite, non-zero extent.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | EdgeList | IfcOrientedEdge | L[1:?] | The list of oriented edges which are concatenated together to form this path. |  | X

Formal Propositions

Rule | Description
--- | ---
IsContinuous | The end vertex of each edge shall be the same as the start vertex of its successor.

##### 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
IfcPath
1 | EdgeList | IfcOrientedEdge | L[1:?] | The list of oriented edges which are concatenated together to form this path. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcPath" type="ifc:IfcPath" substitutionGroup="ifc:IfcTopologicalRepresentationItem" nillable="true"/>
<xs:complexType name="IfcPath">
<xs:complexContent>
<xs:extension base="ifc:IfcTopologicalRepresentationItem">
<xs:sequence>
<xs:element name="EdgeList">
<xs:complexType>
<xs:sequence>
<xs:element ref="ifc:IfcOrientedEdge" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcOrientedEdge"/>
<xs:attribute ref="ifc:cType" fixed="list-unique"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPath
SUBTYPE OF (IfcTopologicalRepresentationItem);
EdgeList : LIST [1:?] OF UNIQUE IfcOrientedEdge;
WHERE
IsContinuous : IfcPathHeadToTail(SELF);
END_ENTITY;

EXPRESS-G diagram

`

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