IfcTransitionCurveSegment2D

Item	Change	Description
IFC4x1 Release Candidate 3
IfcTransitionCurveSegment2D	ADDED
IFC4x1 Final
IfcTransitionCurveSegment2D
StartRadius	MODIFIED	Type changed from IfcLengthMeasure to IfcPositiveLengthMeasure.
EndRadius	MODIFIED	Type changed from IfcLengthMeasure to IfcPositiveLengthMeasure.

Semantic definitions at the entity

Entity definition

An IfcTransitionCurveSegment2D is a curve that transitions between a straight line and a circular arc (or the reverse).

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
4	StartRadius	IfcPositiveLengthMeasure	?	The radius of the curve at the start point. If the radius is not provided by a value, i.e. being “NIL” it is interpreted as INFINITE – the StartPoint is at the point, where it does not have a curvature.	X
5	EndRadius	IfcPositiveLengthMeasure	?	The radius of the curve at the end point. If the radius is not provided by a value, i.e. being “NIL” it is interpreted as INFINITE – the end point is at the point, where it does not have a curvature.	X
6	IsStartRadiusCCW	IfcBoolean		Indication of the curve starting counter-clockwise or clockwise. The orientation of the curve is IsCcw=”true”, if the spiral arc goes counter-clockwise as seen from the start point and start direction, or “to the left", and with IsCcw=”false” if the spiral arc goes clockwise, or “to the right”.	X
7	IsEndRadiusCCW	IfcBoolean		Indication of the curve ending counter-clockwise or clockwise. The orientation of the clothoidal arc is IsCcw=”true”, if the spiral arc goes counter-clockwise as seen towards the end point and end direction, or “to the left", and with IsCcw=”false” if the spiral arc goes clockwise, or “to the right”.	X
8	TransitionCurveType	IfcTransitionCurveType		Indicates the specific type of transition curve.	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
IfcCurve
	Dim :=IfcCurveDim(SELF)	IfcDimensionCount		The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.	X
IfcBoundedCurve
IfcCurveSegment2D
1	StartPoint	IfcCartesianPoint		The start point of the 2D curve as x/y coordinates defined by a 2D Cartesian point.	X
2	StartDirection	IfcPlaneAngleMeasure		The direction of the tangent at the start point. Direction value 0. indicates a curve with a start tangent along the positive x-axis. Values increases counter-clockwise, and decreases clockwise. Depending on the plane angle unit, either degree or radians, the sensible range is -360° ≤ n ≤ 360° (or -2π ≤ n ≤ 2π). Values larger then a full circle (>\|360°\| or >\|2 π\| shall not be used.	X
3	SegmentLength	IfcPositiveLengthMeasure		The length along the curve	X
IfcTransitionCurveSegment2D
4	StartRadius	IfcPositiveLengthMeasure	?	The radius of the curve at the start point. If the radius is not provided by a value, i.e. being “NIL” it is interpreted as INFINITE – the StartPoint is at the point, where it does not have a curvature.	X
5	EndRadius	IfcPositiveLengthMeasure	?	The radius of the curve at the end point. If the radius is not provided by a value, i.e. being “NIL” it is interpreted as INFINITE – the end point is at the point, where it does not have a curvature.	X
6	IsStartRadiusCCW	IfcBoolean		Indication of the curve starting counter-clockwise or clockwise. The orientation of the curve is IsCcw=”true”, if the spiral arc goes counter-clockwise as seen from the start point and start direction, or “to the left", and with IsCcw=”false” if the spiral arc goes clockwise, or “to the right”.	X
7	IsEndRadiusCCW	IfcBoolean		Indication of the curve ending counter-clockwise or clockwise. The orientation of the clothoidal arc is IsCcw=”true”, if the spiral arc goes counter-clockwise as seen towards the end point and end direction, or “to the left", and with IsCcw=”false” if the spiral arc goes clockwise, or “to the right”.	X
8	TransitionCurveType	IfcTransitionCurveType		Indicates the specific type of transition curve.	X

Formal representations

XML Specification

 <xs:element name="IfcTransitionCurveSegment2D" type="ifc:IfcTransitionCurveSegment2D" substitutionGroup="ifc:IfcCurveSegment2D" nillable="true"/>

 <xs:complexType name="IfcTransitionCurveSegment2D">

  <xs:complexContent>

   <xs:extension base="ifc:IfcCurveSegment2D">

    <xs:attribute name="StartRadius" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

    <xs:attribute name="EndRadius" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

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

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

    <xs:attribute name="TransitionCurveType" type="ifc:IfcTransitionCurveType" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcTransitionCurveSegment2D

 SUBTYPE OF (IfcCurveSegment2D);

  StartRadius : OPTIONAL IfcPositiveLengthMeasure;

  EndRadius : OPTIONAL IfcPositiveLengthMeasure;

  IsStartRadiusCCW : IfcBoolean;

  IsEndRadiusCCW : IfcBoolean;

  TransitionCurveType : IfcTransitionCurveType;

END_ENTITY;

 EXPRESS-G diagram

IfcTransitionCurveSegment2D

Semantic definitions at the entity

Inherited definitions from supertypes

Examples

Formal representations