8.9.3.41 IfcOffsetCurve3D
8.9.3.41.1 Semantic definition
An IfcOffsetCurve3D is a curve defined by an offset in 3D space from its BasisCurve.
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 three-dimensional.Informal Propositions
- At no point on the curve shall ref direction be parallel, or opposite to, the direction of the tangent vector.
8.9.3.41.2 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
8.9.3.41.3 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 | |||
| IfcOffsetCurve3D (3) | |||
| 2 | Distance | IfcLengthMeasure |
The distance of the offset curve from the basis curve. The distance may be positive, negative or zero. |
| 3 | SelfIntersect | IfcLogical |
An indication of whether the offset curve self-intersects, this is for information only. |
| 4 | RefDirection | IfcDirection |
The direction used to define the direction of the offset curve 3d from the basis curve. |
8.9.3.41.4 Formal propositions
| Name | Description |
|---|---|
| DimIs2D |
The underlying curve shall be defined in three-dimensional space. |
|
|
8.9.3.41.5 Formal representation
ENTITY IfcOffsetCurve3D
SUBTYPE OF (IfcOffsetCurve);
Distance : IfcLengthMeasure;
SelfIntersect : IfcLogical;
RefDirection : IfcDirection;
WHERE
DimIs2D : BasisCurve.Dim = 3;
END_ENTITY;