IfcBoundaryCurve

IfcBoundaryCurve定义充当曲面边界的曲线。

注：定义根据ISO/CD 10303-42:1992

边界曲线是一种适合定义曲面边界的有界曲线。

注：实体改编自ISO10303-42中定义的边界曲线。

IFC4中增加的新实体

Formal Propositions

Rule	Description
IsClosed	The derived ClosedCurve attribute of IfcCompositeCurve supertype shall be TRUE.

 

#	Attribute	Type	Cardinality	Description	C
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @AssignedItems	S[0:1]	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.	X
	StyledByItem	IfcStyledItem @Item	S[0:1]	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.	X
IfcGeometricRepresentationItem
IfcCurve
	Dim :=IfcCurveDim(SELF)	IfcDimensionCount	[1:1]	The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.	X
IfcBoundedCurve
IfcCompositeCurve
1	Segments	IfcCompositeCurveSegment	L[1:?]	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.	X
2	SelfIntersect	IfcLogical	[1:1]	Indication of whether the curve intersects itself or not; this is for information only.	X
	NSegments :=SIZEOF(Segments)	IfcInteger	[1:1]	The number of component curves.	X
	ClosedCurve :=Segments[NSegments].Transition <> Discontinuous	IfcLogical	[1:1]	Indication whether the curve is closed or not; this is derived from the transition code of the last segment.	X
IfcCompositeCurveOnSurface
	BasisSurface :=IfcGetBasisSurface(SELF)	IfcSurface	S[0:1]	The surface on which the composite curve is defined.	X
IfcBoundaryCurve