IFC 4.3.x development

8.7.3.5 IfcConnectionCurveGeometry

8.7.3.5.1 Semantic definitions at the entity

IfcConnectionCurveGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a curve or at an edge with curve geometry associated. It is envisioned as a control that applies to the element connection relationships.

The IfcCurve (or the IfcEdgeCurve with an associated IfcCurve) at the CurveOnRelatingElement attribute defines the curve where the basic geometry items of the connected elements connects. The curve geometry and coordinates are provided within the local coordinate system of the RelatingElement, as specified at the IfcRelConnects subtype that utilizes the IfcConnectionCurveGeometry. Optionally, the same curve geometry and coordinates can also be provided within the local coordinate system of the RelatedElement by using the CurveOnRelatedElement attribute.

EXAMPLE  The connection relationship between two walls has a geometric constraint which describes the end caps (or cut-off of the wall ends) by a CurveOnRelatingElement for the first wall and a CurveOnRelatedElement for the second wall. The exact usage of the IfcConnectionCurveGeometry is further defined in the geometry use sections of the elements that use it.

The available geometry for the connection constraint may be further restricted to only allow straight segments by applying IfcPolyline only. Such an usage constraint is provided at the object definition of the IfcElement subtype, utilizing the element connection by referring to the subtype of IfcRelConnects with the associated IfcConnectionCurveGeometry.

HISTORY  New entity in IFC1.5.

IFC2x CHANGE  Renamed from IfcLineConnectionGeometry.

IFC2x3 CHANGE  The provision of topology with associated geometry, IfcEdgeCurve, is enabled by using the IfcCurveOrEdgeCurve.

8.7.3.5.1 Attributes

#Attribute Type Description
IfcConnectionGeometry
IfcConnectionCurveGeometry
1CurveOnRelatingElementIfcCurveOrEdgeCurve The bounded curve at which the connected objects are aligned at the relating element, given in the LCS of the relating element.
2CurveOnRelatedElement OPTIONAL IfcCurveOrEdgeCurveThe bounded curve at which the connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.

8.7.3.5.2 Entity inheritance

dot_inheritance IfcConnectionCurveGeometry IfcConnectionCurveGeometry IfcConnectionGeometry IfcConnectionGeometry IfcConnectionCurveGeometry->IfcConnectionGeometry IfcConnectionGeometry_children 3 more... IfcConnectionGeometry_children->IfcConnectionGeometry

8.7.3.5.3 Formal representations

ENTITY IfcConnectionCurveGeometry
 SUBTYPE OF (IfcConnectionGeometry);
	CurveOnRelatingElement : IfcCurveOrEdgeCurve;
	CurveOnRelatedElement : OPTIONAL IfcCurveOrEdgeCurve;
END_ENTITY;