IfcCurveSegment

Item	SPF	XML	Change	Description
IFC4x3_RC1 to IFC4x3_RC2
IfcCurveSegment			ADDED
IFC4x3_RC2 to IFC4x3_RC3
IfcCurveSegment
UsingCurves			ADDED
IFC4x3_RC2 Update
IfcCurveSegment
Placement		X	MODIFIED	Name changed from StartPlacement to Placement.
SegmentStart		X	MODIFIED	Name changed from SegmentLength to SegmentStart.
SegmentLength	X	X	MODIFIED	Name changed from ParentCurve to SegmentLength. Type changed from IfcCurve to IfcCurveMeasureSelect.
ParentCurve			ADDED

Semantic definitions at the entity

Entity definition

A type of segment positioned along a curve cutting a segment from the parent curve. The positioning curve (StartPlacement.PlacementMeasuredAlong) does not neccessarly correspond with the ParentCurve.

Attribute definitions

#	Attribute	Type	Description	G
2	Placement	IfcPlacement	Placement in the context of the curve using this segment. As insertion point SegmentStart is the reference point of Placement. RefDirection of Placement also specifies the sense of the trimmed segment of ParentCurve. RefDirection is bound to the paramettrization sense of the segment.	X
3	SegmentStart	IfcCurveMeasureSelect	First trimming point of the curve segment on the ParentCurve. This point is used as the insertion point into the segmented, gradient or composite curve using this segment.	X
4	SegmentLength	IfcCurveMeasureSelect	Length of segment measured as length or parameter value from SegmentStart. The sign of this value defines the sense agreement.	X
5	ParentCurve	IfcCurve	Curve to be used as base for the segment definition.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
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. 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.	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. IFC2x3 CHANGE The inverse attribute StyledByItem has been added.	X
IfcGeometricRepresentationItem
IfcSegment
1	Transition	IfcTransitionCode		Connectivity between the continuous segments is not enforced per se to be tangential. Setting "TangentialContinuity" to True means that the current segment shall continue with tangential continuity to the previous one.	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 :=IfcSegmentDim(SELF)	IfcDimensionCount		The space dimensionality of this class, defined by the dimensionality of the first ParentCurve.	X
IfcCurveSegment
2	Placement	IfcPlacement		Placement in the context of the curve using this segment. As insertion point SegmentStart is the reference point of Placement. RefDirection of Placement also specifies the sense of the trimmed segment of ParentCurve. RefDirection is bound to the paramettrization sense of the segment.	X
3	SegmentStart	IfcCurveMeasureSelect		First trimming point of the curve segment on the ParentCurve. This point is used as the insertion point into the segmented, gradient or composite curve using this segment.	X
4	SegmentLength	IfcCurveMeasureSelect		Length of segment measured as length or parameter value from SegmentStart. The sign of this value defines the sense agreement.	X
5	ParentCurve	IfcCurve		Curve to be used as base for the segment definition.	X

Formal representations

XML Specification

 <xs:element name="IfcCurveSegment" type="ifc:IfcCurveSegment" substitutionGroup="ifc:IfcSegment" nillable="true"/>

 <xs:complexType name="IfcCurveSegment">

  <xs:complexContent>

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

    <xs:sequence>

     <xs:element name="Placement" type="ifc:IfcPlacement" nillable="true"/>

     <xs:element name="SegmentStart">

      <xs:complexType>

       <xs:group ref="ifc:IfcCurveMeasureSelect"/>

      </xs:complexType>

     </xs:element>

     <xs:element name="SegmentLength">

      <xs:complexType>

       <xs:group ref="ifc:IfcCurveMeasureSelect"/>

      </xs:complexType>

     </xs:element>

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

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcCurveSegment

 SUBTYPE OF (IfcSegment);

  Placement : IfcPlacement;

  SegmentStart : IfcCurveMeasureSelect;

  SegmentLength : IfcCurveMeasureSelect;

  ParentCurve : IfcCurve;

END_ENTITY;

 EXPRESS-G diagram