IFC 4.3.0.1 (IFC4X3_TC1)

8.9.3.38 IfcLine

8.9.3.38.1 Semantic definition

The IfcLine is an unbounded line parameterized by an IfcCartesianPoint and an IfcVector. The magnitude of the IfcVector affects the parameterization of the line, but it does not bound the line.

line examples
Figure 8.9.3.38.A — Unbounded _IfcLine_ and bounded _IfcTrimmedCurve_

P = Pnt V = Dir λ(u) = P + uV and the parametric range is: -∞ < u < ∞

8.9.3.38.2 Entity inheritance

8.9.3.38.3 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
IfcLine (2)
1 Pnt IfcCartesianPoint

The location of the IfcLine.

2 Dir IfcVector

The direction of the IfcLine, the magnitude and units of Dir affect the parameterization of the line.

Table 8.9.3.38.C

8.9.3.38.4 Formal propositions

Name Description
SameDim

The dimensionality of the Pnt, provided by IfcCartesianPoint, shall be the same as the dimensionality of the Dir, provided by IfcVector.

Dir.Dim = Pnt.Dim
Table 8.9.3.38.D

8.9.3.38.5 Examples

8.9.3.38.6 Formal representation

ENTITY IfcLine
 SUBTYPE OF (IfcCurve);
	Pnt : IfcCartesianPoint;
	Dir : IfcVector;
 WHERE
	SameDim : Dir.Dim = Pnt.Dim;
END_ENTITY;

8.9.3.38.7 References

8.9.3.38.8 Changelog

8.9.3.38.8.1 IFC4

  • where rule, SameDim
  • where rule, WR1