IFC 4.3.0.0 (IFC4X3) final

4.7.1.2.4 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] Transition [1:1] UsingCurves [1:?] Placement [1:1] SegmentStart [1:1] SegmentLength [1:1] ParentCurve [1:1] IfcCosineSpiral IfcCosineSpiral LayerAssignment [0:1] StyledByItem [0:1] Position [0:1] CosineTerm [1:1] 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
Figure 4.7.1.2.4.A