IFC (IFC4X3_ADD1) development Cosine Spiral Transition Segment

The cosine spiral transition segment is a special case of a spiral where the curvature rate of change is a cosine 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 dependent on segment length L: CosineTerm = L Constant = 1

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] IfcCosineSpiral IfcCosineSpiral      LayerAssignment [0:1]      StyledByItem [0:1] 1. Position [0:1] 2. CosineTerm [1:1] 3. ConstantTerm [0:1] IfcCurveSegment:ParentCurve1->IfcCosineSpiral:IfcCosineSpiral0 IfcParameterValue_0 IfcParameterValue IfcCurveSegment:SegmentStart1->IfcParameterValue_0:IfcParameterValue0 IfcParameterValue_1 IfcParameterValue IfcCurveSegment:SegmentLength1->IfcParameterValue_1:IfcParameterValue0 IfcLengthMeasure IfcLengthMeasure IfcCosineSpiral:CosineTerm1->IfcLengthMeasure:IfcLengthMeasure0 IfcReal IfcReal IfcCosineSpiral:ConstantTerm1->IfcReal:IfcReal0

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