8.9.3.44 IfcPcurve
8.9.3.44.1 Semantic definition
The IfcPcurve is a curve defined within the parameter space of its reference surface.
Definition according to ISO/CD 10303-42:1992 A pcurve is a curve which lies on the basis of a surface and is defined in the parameter space of that surface. The basis curve is a curve defined in the two-dimensional parametric space of a reference basis surface. Although it is defined by a curve in two dimensional space, the variables involved are u and v, which occur in the parametric representation of the referenced surface, rather than the x, y, Cartesian coordinates. The basis curve is only defined within the parametric range of the surface. Entity adapted from pcurve in ISO 10303-42. New entity in IFC4.8.9.3.44.2 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
8.9.3.44.3 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 | |||
| IfcPcurve (2) | |||
| 1 | BasisSurface | IfcSurface |
No description available. |
| 2 | ReferenceCurve | IfcCurve |
No description available. |
8.9.3.44.4 Formal propositions
| Name | Description |
|---|---|
| DimIs2D |
The dimensionality of the parameter space curve shall be 2. |
|
|
8.9.3.44.5 Formal representation
ENTITY IfcPcurve
SUBTYPE OF (IfcCurve);
BasisSurface : IfcSurface;
ReferenceCurve : IfcCurve;
WHERE
DimIs2D : ReferenceCurve.Dim = 2;
END_ENTITY;