IFC 4.3.0.1 (IFC4X3) development

4.7.1.2.11 Viennese Bend Transition Segment

The Viennese Bend (R) transition segment is a kinematic high performance transition. The horizontal curvature is assembled by the baseformula and a term depending on the height of the gravity center line relative to the track plane and by the applied cant values at the start and the end of the segment.

The x/y coordinates can be calculated using a 7th order polynominal spiral.

The following diagram shows the generic classes and relationships used when applying this concept.

G IfcCurveSegment IfcCurveSegment      LayerAssignment [0:1]      StyledByItem [0:1] 1. Transition [1:1]      UsingCurves [1:?] 2. Placement [1:1] 3. SegmentStart [1:1] 4. SegmentLength [1:1] 5. ParentCurve [1:1] IfcSeventhOrderPolynomialSpiral IfcSeventhOrderPolynomialSpiral      LayerAssignment [0:1]      StyledByItem [0:1] 1. Position [0:1] 2. SepticTerm [1:1] 3. SexticTerm [0:1] 4. QuinticTerm [0:1] 5. QuarticTerm [0:1] 6. CubicTerm [0:1] 7. QuadraticTerm [0:1] 8. LinearTerm [0:1] 9. ConstantTerm [0:1] IfcCurveSegment:ParentCurve1->IfcSeventhOrderPolynomialSpiral:IfcSeventhOrderPolynomialSpiral0 IfcParameterValue_0 IfcParameterValue IfcCurveSegment:SegmentStart1->IfcParameterValue_0:IfcParameterValue0 IfcParameterValue_1 IfcParameterValue IfcCurveSegment:SegmentLength1->IfcParameterValue_1:IfcParameterValue0 IfcReal IfcReal IfcSeventhOrderPolynomialSpiral:ConstantTerm1->IfcReal:IfcReal0 IfcLengthMeasure_0 IfcLengthMeasure IfcSeventhOrderPolynomialSpiral:QuadraticTerm1->IfcLengthMeasure_0:IfcLengthMeasure0 IfcLengthMeasure_1 IfcLengthMeasure IfcSeventhOrderPolynomialSpiral:CubicTerm1->IfcLengthMeasure_1:IfcLengthMeasure0 IfcLengthMeasure_2 IfcLengthMeasure IfcSeventhOrderPolynomialSpiral:QuarticTerm1->IfcLengthMeasure_2:IfcLengthMeasure0 IfcLengthMeasure_3 IfcLengthMeasure IfcSeventhOrderPolynomialSpiral:QuinticTerm1->IfcLengthMeasure_3:IfcLengthMeasure0 IfcLengthMeasure_4 IfcLengthMeasure IfcSeventhOrderPolynomialSpiral:SexticTerm1->IfcLengthMeasure_4:IfcLengthMeasure0 IfcLengthMeasure_5 IfcLengthMeasure IfcSeventhOrderPolynomialSpiral:SepticTerm1->IfcLengthMeasure_5:IfcLengthMeasure0
Figure 4.7.1.2.11.A

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