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8.9.3.25 IfcCurve

RV ⓘ
AbV ⓘ

ABSTRACT This definition may not be instantiated

8.9.3.25.1 Semantic definition

An IfcCurve is a curve in two-dimensional or three-dimensional space. It includes definitions for bounded and unbounded curves.

Definition according to ISO 10303-42: A curve can be envisioned as the path of a point moving in its coordinate space. Entity adapted from curve defined in ISO 10303-42 New entity in IFC1.0

Informal Propositions

  1. A curve shall be arcwise connected
  2. A curve shall have an arc length greater than zero.

8.9.3.25.2 Entity inheritance

8.9.3.25.3 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.

The inverse attribute LayerAssignments has been added. 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.

The inverse attribute StyledByItem has been added.
Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes
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.
Table 8.9.3.25.A

8.9.3.25.4 Formal representation 

ENTITY IfcCurve
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcBoundedCurve
	,IfcConic
	,IfcLine
	,IfcOffsetCurve
	,IfcPcurve
	,IfcPolynomialCurve
	,IfcSpiral
	,IfcSurfaceCurve))
 SUBTYPE OF (IfcGeometricRepresentationItem);
 DERIVE
	 Dim : IfcDimensionCount := IfcCurveDim(SELF);
END_ENTITY;

8.9.3.25.5 References

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