8.9.3.40 IfcOffsetCurve2D
8.9.3.40.1 Semantic definition
An IfcOffsetCurve2D is a curve defined by an offset in 2D space from its BasisCurve.
where T is the unit tangent vector to the basis curve C(u) at parameter value u, and d is distance. The underlying curve shall be two-dimensional.8.9.3.40.2 Entity inheritance
-
- 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
8.9.3.40.3 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. The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. |
| IfcOffsetCurve (1) | |||
| 1 | BasisCurve | IfcCurve |
The curve that is being offset. |
| Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes | |||
| IfcOffsetCurve2D (2) | |||
| 2 | Distance | IfcLengthMeasure |
The distance of the offset curve from the basis curve. distance may be positive, negative or zero. A positive value of distance defines an offset in the direction which is normal to the curve in the sense of an anti-clockwise rotation through 90 degrees from the tangent vector T at the given point. (This is in the direction of orthogonal complement(T).) |
| 3 | SelfIntersect | IfcLogical |
An indication of whether the offset curve self-intersects; this is for information only. |
8.9.3.40.4 Formal propositions
| Name | Description |
|---|---|
| DimIs2D |
The underlying curve shall be defined in two-dimensional space. |
|
|
8.9.3.40.5 Formal representation
ENTITY IfcOffsetCurve2D
SUBTYPE OF (IfcOffsetCurve);
Distance : IfcLengthMeasure;
SelfIntersect : IfcLogical;
WHERE
DimIs2D : BasisCurve.Dim = 2;
END_ENTITY;