IFC (IFC4X3_TC1) IfcEdge Semantic definition

An IfcEdge defines two vertices being connected topologically. The geometric representation of the connection between the two vertices defaults to a straight line if no curve geometry is assigned using the subtype IfcEdgeCurve. The IfcEdge can therefore be used to exchange straight edges without an associated geometry provided by IfcLine or IfcPolyline thought IfcEdgeCurve.EdgeGeometry.

edge representation
Figure — Edge representation
Image where V = 1 or 2, and G^e^ = 1 or 0. Specifically, the topological edge defining data shall satisfy: > * an edge has two vertices Image * the vertices need not be distinct Image * Equation shall hold Image

Informal Propositions:

  1. The edge has dimensionality 1.
  2. The extent of an edge shall be finite and nonzero. Entity inheritance Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

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.

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.

Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes
IfcEdge (2)
1 EdgeStart IfcVertex

Start point (vertex) of the edge.

2 EdgeEnd IfcVertex

End point (vertex) of the edge. The same vertex can be used for both EdgeStart and EdgeEnd.

Table Formal representation

 SUBTYPE OF (IfcTopologicalRepresentationItem);
	EdgeStart : IfcVertex;
	EdgeEnd : IfcVertex;
END_ENTITY; References