IFC 4.3.0.1 (IFC4X3) development

8.9.3.67 IfcSpiral

ABSTRACT This definition may not be instantiated

8.9.3.67.1 Semantic definition

Spirals are curves that revolve around a point while increasing its length. In general, these curves are parameterized in the following way: x = r(φ) cosφ y = r(φ) sinφ

In the case of the clothoid and higher order transition spirals, the parametrization is: x = ∫cos &Theta dl y = ∫sin &Theta dl

where &Theta is the deflection or bearing angle and dl the differential of the spiral length.

8.9.3.67.2 Entity inheritance

8.9.3.67.3 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.

Click to show 3 hidden inherited attributes Click to hide 3 inherited attributes
IfcSpiral (1)
1 Position OPTIONAL IfcAxis2Placement

No description available.

Table 8.9.3.67.A

8.9.3.67.4 Formal representation

ENTITY IfcSpiral
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcClothoid
	,IfcCosineSpiral
	,IfcSecondOrderPolynomialSpiral
	,IfcSeventhOrderPolynomialSpiral
	,IfcSineSpiral
	,IfcThirdOrderPolynomialSpiral))
 SUBTYPE OF (IfcCurve);
	Position : OPTIONAL IfcAxis2Placement;
END_ENTITY;

8.9.3.67.5 References

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8.9.3.67.6 Changelog

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