IFC (IFC4X3_ADD2) under development Sine Spiral Transition Segment

The sine spiral transition segment is a special case of a spiral where the curvature rate of change is a sine function and the terms are dependent on the length L measured from the inflection point. The parameter value is defined as the deflection i.e. bearing angle &Theta.

The values of its individual terms are identical and equal to the length of the segment L: SineTerm = L LinearTerm = L

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] IfcSineSpiral IfcSineSpiral      LayerAssignment [0:1]      StyledByItem [0:1] 1. Position [1:1] 2. SineTerm [1:1] 3. LinearTerm [0:1] 4. ConstantTerm [0:1] IfcCurveSegment:ParentCurve1->IfcSineSpiral:IfcSineSpiral0 IfcLengthMeasure_0 IfcLengthMeasure IfcCurveSegment:SegmentStart1->IfcLengthMeasure_0:IfcLengthMeasure0 IfcLengthMeasure_1 IfcLengthMeasure IfcCurveSegment:SegmentLength1->IfcLengthMeasure_1:IfcLengthMeasure0 IfcSineSpiral:SineTerm1->IfcLengthMeasure_0:IfcLengthMeasure0 IfcSineSpiral:LinearTerm1->IfcLengthMeasure_1:IfcLengthMeasure0

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