8.9.3.9 IfcBoundaryCurve

8.9.3.9.1 Semantic definition

An IfcBoundaryCurve defines a curve acting as the boundary of a surface.

8.9.3.9.2 Entity inheritance

8.9.3.9.3 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. 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.
IfcCurve (1)
*	Dim	IfcDimensionCount	This attribute is formally derived. `IfcCurveDim(SELF)` The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.
IfcCompositeCurve (4)
1	Segments	LIST [1:?] OF IfcSegment	The component bounded curves, their transitions and senses. The transition attribute for the last segment defines the transition between the end of the last segment and the start of the first; this transition attribute may take the value discontinuous, which indicates an open curve. NOTE : For IfcGradientCurve and IfcSegmentedReferenceCurve the segments define the interpolation between segment start and and segment end.
2	SelfIntersect	IfcLogical	Indication of whether the curve intersects itself or not; this is for information only.
*	NSegments	IfcInteger	This attribute is formally derived. `SIZEOF(Segments)` The number of component curves.
*	ClosedCurve	IfcLogical	This attribute is formally derived. `Segments[NSegments].Transition <> Discontinuous` Indication whether the curve is closed or not; this is derived from the transition code of the last segment.
Click to show 7 hidden inherited attributes
IfcCompositeCurveOnSurface (1)
*	BasisSurface	SET [0:1] OF IfcSurface	This attribute is formally derived. `IfcGetBasisSurface(SELF)` The surface on which the composite curve is defined.

Table 8.9.3.9.A

8.9.3.9.4 Formal propositions

Name	Description
IsClosed	The derived ClosedCurve attribute of IfcCompositeCurve supertype shall be TRUE.
`SELF\IfcCompositeCurve.ClosedCurve`

Table 8.9.3.9.B

8.9.3.9.5 Formal representation

 ENTITY IfcBoundaryCurve
 SUPERTYPE OF (ONEOF
	(IfcOuterBoundaryCurve))
 SUBTYPE OF (IfcCompositeCurveOnSurface);
 WHERE
	IsClosed : SELF\IfcCompositeCurve.ClosedCurve;
END_ENTITY;

8.9.3.9 IfcBoundaryCurve

8.9.3.9.1 Semantic definition

8.9.3.9.2 Entity inheritance

8.9.3.9.3 Attributes

8.9.3.9.4 Formal propositions

8.9.3.9.5 Formal representation

8.9.3.9.6 References

8.9.3.9.7 Changelog

8.9.3.9.7.1 IFC4

	ENTITY IfcBoundaryCurve
	SUPERTYPE OF (ONEOF
	(IfcOuterBoundaryCurve))
	SUBTYPE OF (IfcCompositeCurveOnSurface);
	WHERE
	IsClosed : SELF\IfcCompositeCurve.ClosedCurve;
	END_ENTITY;