IfcCompositeCurveSegment

IfcCompositeCurve segment是一条有界曲线，其唯一目的是成为IfcCompositeCurve中的一段。

注释定义符合ISO/CD 10303-42:1992

复合曲线段是一条有界曲线，它与过渡信息一起用于构造复合曲线。

注：实体改编自ISO 10303-42中定义的复合曲线段。

在IFC1.0中增加的新实体

Formal Propositions

Rule	Description
ParentIsBoundedCurve	The parent curve shall be a bounded curve.

 

#	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
IfcCompositeCurveSegment
1	Transition	IfcTransitionCode	[1:1]	The state of transition (i.e., geometric continuity from the last point of this segment to the first point of the next segment) in a composite curve.	X
2	SameSense	IfcBoolean	[1:1]	An indicator of whether or not the sense of the segment agrees with, or opposes, that of the parent curve. If SameSense is false, the point with highest parameter value is taken as the first point of the segment. NOTE  If the datatype of ParentCurve is IfcTrimmedCurve, the value of SameSense overrides the value of IfcTrimmedCurve.SenseAgreement	X
3	ParentCurve	IfcCurve	[1:1]	The bounded curve which defines the geometry of the segment.	X
	UsingCurves	IfcCompositeCurve @Segments	S[1:?]	The set of composite curves which use this composite curve segment as a segment. This set shall not be empty.	X
	Dim :=ParentCurve.Dim	IfcDimensionCount	[1:1]	The space dimensionality of this class, defined by the dimensionality of the first ParentCurve.	X

 

EXPRESS Specification

ENTITY IfcCompositeCurveSegment
 SUPERTYPE OF(IfcReparametrisedCompositeCurveSegment)
 SUBTYPE OF (IfcGeometricRepresentationItem);
  Transition : IfcTransitionCode;
  SameSense : IfcBoolean;
  ParentCurve : IfcCurve;
 INVERSE
  UsingCurves : SET [1:?] OF IfcCompositeCurve FOR Segments;
 DERIVE
  Dim : IfcDimensionCount := ParentCurve.Dim;
 WHERE
  ParentIsBoundedCurve : ('IFCGEOMETRYRESOURCE.IFCBOUNDEDCURVE' IN TYPEOF(ParentCurve));
END_ENTITY;