IFC 4.3.x development

8.20.3.19 IfcVertexLoop

8.20.3.19.1 Semantic definitions at the entity

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:

Image

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.

8.20.3.19.1 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
IfcLoop
IfcVertexLoop
1 LoopVertex IfcVertex The vertex which defines the entire loop.

8.20.3.19.2 Entity inheritance

dot_inheritance IfcVertexLoop IfcVertexLoop IfcLoop IfcLoop IfcVertexLoop->IfcLoop IfcEdgeLoop IfcEdgeLoop IfcEdgeLoop->IfcLoop IfcTopologicalRepresentationItem IfcTopologicalRepresentationItem IfcLoop->IfcTopologicalRepresentationItem IfcPolyLoop IfcPolyLoop IfcPolyLoop->IfcLoop IfcTopologicalRepresentationItem_children 6 more... IfcTopologicalRepresentationItem_children->IfcTopologicalRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcTopologicalRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.20.3.19.3 Formal representations

ENTITY IfcVertexLoop
 SUBTYPE OF (IfcLoop);
	LoopVertex : IfcVertex;
END_ENTITY;