8.9.3.37 IfcLine
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.
A line segment is defined using either the IfcPolyline with two Points, or the IfcTrimmedCurve with BasisCurve being an IfcLine. Figure 8.9.3.37.A illustrates an unbounded IfcLine and a bounded IfcTrimmedCurve. A bounded line starting at 0.,0. and ending at 0.,2. can be defined by:
P = Pnt V = Dir λ(u) = P + uV and the parametric range is: -∞ < u < ∞
8.9.3.37.2 Entity inheritance
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- IfcCurve
- IfcAnnotationFillArea
- IfcBooleanResult
- IfcBoundingBox
- IfcCartesianPointList
- IfcCartesianTransformationOperator
- IfcCsgPrimitive3D
- IfcDirection
- IfcFaceBasedSurfaceModel
- IfcFillAreaStyleHatching
- IfcFillAreaStyleTiles
- IfcGeometricSet
- IfcHalfSpaceSolid
- IfcLightSource
- IfcPlacement
- IfcPlanarExtent
- IfcPoint
- IfcSectionedSpine
- IfcSegment
- IfcShellBasedSurfaceModel
- IfcSolidModel
- IfcSurface
- IfcTessellatedItem
- IfcTextLiteral
- IfcVector
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. 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. |
|
| IfcCurve (1) | |||
| * | Dim | IfcDimensionCount |
This attribute is formally derived. 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. |
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. |
|
|
8.9.3.37.5 Examples
8.9.3.37.6 Formal representation
ENTITY IfcLine
SUBTYPE OF (IfcCurve);
Pnt : IfcCartesianPoint;
Dir : IfcVector;
WHERE
SameDim : Dir.Dim = Pnt.Dim;
END_ENTITY;