IFC 4.3.x development IfcSpiral

Change log


added Semantic definitions at the entity

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. Attributes

# Attribute Type Description
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.

> IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.

> IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
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.

> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
Dim INVALID The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.
1 Position OPTIONAL IfcAxis2Placement Entity inheritance

dot_inheritance IfcSpiral_children 5 more... IfcSpiral IfcSpiral IfcSpiral_children->IfcSpiral IfcCurve IfcCurve IfcSpiral->IfcCurve IfcCurve_children 7 more... IfcCurve_children->IfcCurve IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcCurve->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem Formal representations

ENTITY IfcSpiral
 SUBTYPE OF (IfcCurve);
	Position : OPTIONAL IfcAxis2Placement;