IFC 4.3.0.1 (IFC4X3_TC1)

# 8.20.3.4 IfcEdge

## 8.20.3.4.1 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.

Informal Propositions:

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

## 8.20.3.4.4 Formal representation

ENTITY IfcEdge
SUPERTYPE OF (ONEOF
(IfcEdgeCurve
,IfcOrientedEdge
,IfcSubedge))
SUBTYPE OF (IfcTopologicalRepresentationItem);
EdgeStart : IfcVertex;
EdgeEnd : IfcVertex;
END_ENTITY;