IFC 4.3.2.20250327 (IFC4X3_ADD2) under development

8.9.3.72 IfcThirdOrderPolynomialSpiral

AbV ⓘ

8.9.3.72.1 Semantic definition

The IfcThirdOrderPolynomialSpiral is a specialization of IfcSpiral. The curvature κ and radius of the curvature ρ, at any point of the curve, are related to the arc length s by the third order formulae:

formula
Figure 8.9.3.72.A

Interpretation of the parameters:

C = SELF\IfcSpiral.Position.Location x = SELF\IfcSpiral.Position.P[1] y = SELF\IfcSpiral.Position.P[2] A3 = CubicTerm A2 = QuadraticTerm A1 = LinearTerm A0 = ContantTerm

and the third order polynomial spiral is parameterized as:

formula
Figure 8.9.3.72.B

where:

formula
Figure 8.9.3.72.C

and the parametric range is: -∞ < u < ∞.

8.9.3.72.2 Entity inheritance

8.9.3.72.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
IfcCurve (1)
IfcSpiral (1)
Click to show 4 hidden inherited attributes
IfcThirdOrderPolynomialSpiral (4)
2 CubicTerm IfcLengthMeasure

The constant that defines the cubic term in the equation which defines the relation between curvature and arc length for the curve.

3 QuadraticTerm OPTIONAL IfcLengthMeasure

The constant that defines the quadratic term in the equation which defines the relation between curvature and arc length for the curve.

4 LinearTerm OPTIONAL IfcLengthMeasure

The constant that defines the linear term in the equation which defines the relation between curvature and arc length for the curve.

5 ConstantTerm OPTIONAL IfcLengthMeasure

The constant that defines the constant term in the equation which defines the relation between curvature and arc length for the curve.

Table 8.9.3.72.D

8.9.3.72.4 Formal representation

ENTITY IfcThirdOrderPolynomialSpiral
SUBTYPE OF (IfcSpiral);
CubicTerm : IfcLengthMeasure;
QuadraticTerm : OPTIONAL IfcLengthMeasure;
LinearTerm : OPTIONAL IfcLengthMeasure;
ConstantTerm : OPTIONAL IfcLengthMeasure;
END_ENTITY;

8.9.3.72.5 References

Edit on Github


Is this page difficult to understand? Let us know!

8.9.3.72.6 Changelog

8.9.3.72.6.1 IFC4.3_DEV_738df036

  • New resource