IFC 4.3.x development

8.20.3.14 IfcPath

Change log

IFC4

additionswhere_rulesIsContinuous
deletionswhere_rulesWR1

IFC4X2

modificationsattributes EdgeList definitionChanged from list[1:?] of unique IfcOrientedEdge to list[1:?] of IfcOrientedEdge

IFC4X3_RC3

modificationsattributes EdgeList definitionChanged from list[1:?] of IfcOrientedEdge to list[1:?] of unique IfcOrientedEdge

8.20.3.14.1 Semantic definitions at the entity

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.

8.20.3.14.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item 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.
IfcTopologicalRepresentationItem
IfcPath
1 EdgeList LIST [1:?] OF UNIQUE IfcOrientedEdge The list of oriented edges which are concatenated together to form this path.

8.20.3.14.2 Entity inheritance

dot_inheritance IfcPath IfcPath IfcTopologicalRepresentationItem IfcTopologicalRepresentationItem IfcPath->IfcTopologicalRepresentationItem IfcTopologicalRepresentationItem_children 6 more... IfcTopologicalRepresentationItem_children->IfcTopologicalRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcTopologicalRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.20.3.14.3 Formal representations

ENTITY IfcPath
 SUBTYPE OF (IfcTopologicalRepresentationItem);
	EdgeList : LIST [1:?] OF UNIQUE IfcOrientedEdge;
 WHERE
	IsContinuous : IfcPathHeadToTail(SELF);
END_ENTITY;