IFC 4.3.0.0 (IFC4X3) final

4.7.1.2.2 Bloss Transition Segment

The Bloss transition segment is a special case of a fifht order spiral where the curvature rate of change is a cubic 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.

Only the cubic and quadratic terms are populated with the following values: QubicTerm = L/³√2 QuadraticTerm = L/√3

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] IfcThirdOrderPolynomialSpiral IfcThirdOrderPolynomialSpiral LayerAssignment [0:1] StyledByItem [0:1] Position [0:1] CubicTerm [1:1] QuadraticTerm [0:1] LinearTerm [0:1] ConstantTerm [0:1] IfcCurveSegment:ParentCurve1->IfcThirdOrderPolynomialSpiral:IfcThirdOrderPolynomialSpiral0 IfcLengthMeasure_0 IfcLengthMeasure IfcThirdOrderPolynomialSpiral:QubicTerm1->IfcLengthMeasure_0:IfcLengthMeasure0 IfcLengthMeasure_1 IfcLengthMeasure IfcThirdOrderPolynomialSpiral:QuadraticTerm1->IfcLengthMeasure_1:IfcLengthMeasure0
Figure 4.7.1.2.2.A