Transition Curve Segment 2D |

Item | SPF | XML | Change | Description |
---|---|---|---|---|

IFC4x1 Release Candidate 3 |
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IfcTransitionCurveSegment2D | ADDED | |||

IFC4x1 Final |
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IfcTransitionCurveSegment2D | ||||

StartRadius | MODIFIED | Type changed from IfcLengthMeasure to IfcPositiveLengthMeasure. | ||

EndRadius | MODIFIED | Type changed from IfcLengthMeasure to IfcPositiveLengthMeasure. | ||

IFC4x2 FINAL |
||||

IfcTransitionCurveSegment2D | ||||

PositioningElement | ADDED |

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

# | 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 |

# | 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 IFC4 CHANGE The inverse attribute | 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 | 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 | |||||

PositioningElement | IfcLinearPositioningElement @Axis | ? | X | ||

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 |

` <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>

```
ENTITY IfcTransitionCurveSegment2D
```

SUBTYPE OF (IfcCurveSegment2D)**;**

StartRadius : OPTIONAL IfcPositiveLengthMeasure;

EndRadius : OPTIONAL IfcPositiveLengthMeasure;

IsStartRadiusCCW : IfcBoolean;

IsEndRadiusCCW : IfcBoolean;

TransitionCurveType : IfcTransitionCurveType;

END_ENTITY;