IFC 4.3.0.1 (IFC4X3) development

8.9.3.64 IfcSeventhOrderPolynomialSpiral

8.9.3.64.1 Semantic definition

The IfcSeventhOrderPolynomialSpiral 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 seventh order formulae:

formula
Figure 8.9.3.64.A

Interpretation of the parameters:

C = SELF\IfcSpiral.Position.Location x = SELF\IfcSpiral.Position.P[1] y = SELF\IfcSpiral.Position.P[2] A7 = SepticTerm A6 = SexticTerm A5 = QuinticTerm A4 = QuarticTerm A3 = CubicTerm A2 = QuadraticTerm A1 = LinearTerm A0 = ContantTerm

and the seventh order polynomial spiral is parameterized as:

formula
Figure 8.9.3.64.B

where:

formula
Figure 8.9.3.64.C

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

8.9.3.64.2 Entity inheritance

8.9.3.64.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

StyledByItem SET [0:1] OF IfcStyledItem FOR Item

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.

IfcCurve (1)
* Dim IfcDimensionCount

This attribute is formally derived.

IfcCurveDim(SELF)

The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.

IfcSpiral (1)
1 Position OPTIONAL IfcAxis2Placement

No description available.

Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes
IfcSeventhOrderPolynomialSpiral (8)
2 SepticTerm IfcLengthMeasure

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

3 SexticTerm OPTIONAL IfcLengthMeasure

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

4 QuinticTerm OPTIONAL IfcLengthMeasure

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

5 QuarticTerm OPTIONAL IfcLengthMeasure

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

6 CubicTerm OPTIONAL IfcLengthMeasure

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

7 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.

8 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.

9 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 8.9.3.64.D

8.9.3.64.4 Formal representation

ENTITY IfcSeventhOrderPolynomialSpiral
 SUBTYPE OF (IfcSpiral);
	SepticTerm : IfcLengthMeasure;
	SexticTerm : OPTIONAL IfcLengthMeasure;
	QuinticTerm : OPTIONAL IfcLengthMeasure;
	QuarticTerm : OPTIONAL IfcLengthMeasure;
	CubicTerm : OPTIONAL IfcLengthMeasure;
	QuadraticTerm : OPTIONAL IfcLengthMeasure;
	LinearTerm : OPTIONAL IfcLengthMeasure;
	ConstantTerm : OPTIONAL IfcLengthMeasure;
END_ENTITY;

8.9.3.64.5 References

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8.9.3.64.6 Changelog

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