IfcCircularArcSegment2D

Item	SPF	XML	Change	Description
IFC4x1 Release Candidate 1
IfcCircularArcSegment2D			ADDED

Semantic definitions at the entity

Entity definition

The circular arc segment uses the inherited attributes StartPoint as the start of the circular arc, StartDirection as the tangent at the start point and SegmentLength as the arc length.


Figure 367 — Circular arc segment 2D	Figure 368 — Circular arc segment 2D CCW

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
4	Radius	IfcPositiveLengthMeasure		The radius of the circular arc	X
5	IsCCW	IfcBoolean		(counter-clockwise or clockwise) as the orientation of the circular arc with Boolean=”true” being counter-clockwise, or “to the left", and Boolean=”false” being clockwise, or “to the right”.	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
IfcCircularArcSegment2D
4	Radius	IfcPositiveLengthMeasure		The radius of the circular arc	X
5	IsCCW	IfcBoolean		(counter-clockwise or clockwise) as the orientation of the circular arc with Boolean=”true” being counter-clockwise, or “to the left", and Boolean=”false” being clockwise, or “to the right”.	X

Formal representations

XML Specification

 <xs:element name="IfcCircularArcSegment2D" type="ifc:IfcCircularArcSegment2D" substitutionGroup="ifc:IfcCurveSegment2D" nillable="true"/>

 <xs:complexType name="IfcCircularArcSegment2D">

  <xs:complexContent>

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

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

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

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcCircularArcSegment2D

 SUBTYPE OF (IfcCurveSegment2D);

  Radius : IfcPositiveLengthMeasure;

  IsCCW : IfcBoolean;

END_ENTITY;

 EXPRESS-G diagram