8.9.3.37 IfcLine

AbV ⓘ

8.9.3.37.1 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 A — Unbounded _IfcLine_ and bounded _IfcTrimmedCurve_

{ .extDef}

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

{ .extDef}

8.9.3.37.2 Entity inheritance

8.9.3.37.3 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. 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.
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 B

8.9.3.37.4 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 C

8.9.3.37.5 Formal representation

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