IfcCompositeCurveSegment

Semantic definitions at the entity

Entity definition

An IfcCompositeCurveSegment is a bounded curve constructed for the sole purpose to be a segment within an IfcCompositeCurve.

NOTE Definition according to ISO/CD 10303-42:1992
A composite curve segment is a bounded curve together with transition information which is used to construct a composite curve.

NOTE Entity adapted from composite_curve_segment defined in ISO 10303-42.

HISTORY New entity in IFC1.0

Attribute definitions

#	Attribute	Type	Cardinality	Description	B
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.
	Dim :=ParentCurve.Dim	IfcDimensionCount	[1:1]	The space dimensionality of this class, defined by the dimensionality of the first ParentCurve.	X

Formal Propositions

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

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	B
IfcRepresentationItem
	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.
	Dim :=ParentCurve.Dim	IfcDimensionCount	[1:1]	The space dimensionality of this class, defined by the dimensionality of the first ParentCurve.	X

Formal representations

XSD Specification

 <xs:element name="IfcCompositeCurveSegment" type="ifc:IfcCompositeCurveSegment" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>

 <xs:complexType name="IfcCompositeCurveSegment">

  <xs:complexContent>

   <xs:extension base="ifc:IfcGeometricRepresentationItem">

    <xs:sequence>

     <xs:element name="ParentCurve" type="ifc:IfcCurve" nillable="true"/>

    </xs:sequence>

    <xs:attribute name="Transition" type="ifc:IfcTransitionCode" use="optional"/>

    <xs:attribute name="SameSense" type="ifc:IfcBoolean" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcCompositeCurveSegment

 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;

 EXPRESS-G diagram

Item	Change	Description
IFC4 to IFC4 ADD1
IfcCompositeCurveSegment
SameSense	MODIFIED	Type changed from BOOLEAN to IfcBoolean.

	Segment einer zusammengesetzten Kurve
	Composite Curve Segment
	Segment de courbe composite