IFC 4.3.0.0 (IFC4X3) final

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.
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.
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.
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.
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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;

8.9.3.9.6 References

8.9.3.9.7 Changelog

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