additions | where_rules | SameDim |

deletions | where_rules | WR1 |

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.

NOTE A line segment is defined using either the

IfcPolylinewith twoPoints, or theIfcTrimmedCurvewithBasisCurvebeing anIfcLine.EXAMPLE Figure 1 illustrates an unbounded

IfcLineand a boundedIfcTrimmedCurve. A bounded line starting at 0.,0. and ending at 0.,2. can be defined by:

IfcLinewithIfcVector.Magnitude: 2.0 ANDIfcTrimmedCurvewithTrim1: 0. andTrim2: 1. (and trimming preference being parameter);IfcLinewithIfcVector.Magnitude: 1.0 ANDIfcTrimmedCurvewithTrim1: 0. andTrim2: 2. (and trimming preference being parameter);IfcLineANDIfcTrimmedCurvewithTrim1::IfcCartesianPoint[0.,0.] andTrim2::IfcCartesianPoint[0.,2.] (and trimming preference being Cartesian) - theIfcVector.Magnitudehas no effect;IfcPolylinewithPoints[1]being 0.,0. andPoints[2]being 0.,2.IfcIndexedPolyCurvewith two indices, pointing into a point list providing the coordinates (0.,0.) and (0.,2.).

NOTE Definition according to ISO/CD 10303-42:1992

A line is an unbounded curve with constant tangent direction. A line is defined by a point and a direction. The positive direction of the line is in the direction of the dir vector. The curve is parameterized as follows:

P= Pnt

V= Dir

λ(u) =P+uVand the parametric range is: -∞ <u< ∞NOTE Entity adapted from

linedefined in ISO 10303-42HISTORY New entity in IFC1.0

# | Attribute | Type | Description |
---|---|---|---|

IfcRepresentationItem | |||

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. | |

IfcGeometricRepresentationItem | |||

IfcCurve | |||

Dim | INVALID | The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. | |

IfcLine | |||

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. |

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