The *IfcCurveBoundedPlane* is a parametric planar surface with curved boundaries defined by one or more boundary curves. The bounded plane is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected.

The *BasisSurface* is an *IfcPlane* that establishes the position coordinate system by *SELF\IfcElementarySurface.Position*. The *OuterBoundary* and the *InnerBoundaries* (if provided) shall lie on the surface of *IfcPlane*. The outer and inner boundary curves shall be defined using the *u*, and *v* values provided by parameterization of the *BasisSurface* as their *x*, and *y* coordinate values.

NOTE Entity defined in analogy to

curve_bounded_surfacedefined in ISO 10303-42.HISTORY New entity in IFC1.5

IFC2x CHANGE The data type of the attribute

OuterBoundaryandInnerBoundarieshas been changed fromIfc2DCompositeCurveto supertypeIfcCurve.

# | 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 | |||

IfcSurface | |||

Dim | INVALID | The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item. > IFC4 CHANGE Derived attribute promoted from subtypes. | |

IfcBoundedSurface | |||

IfcCurveBoundedPlane | |||

1 | BasisSurface | IfcPlane | The surface to be bound. |

2 | OuterBoundary | IfcCurve | The outer boundary of the surface. |

3 | InnerBoundaries | SET [0:?] OF IfcCurve | An optional set of inner boundaries. They shall not intersect each other or the outer boundary. |

ENTITY IfcCurveBoundedPlane SUBTYPE OF (IfcBoundedSurface); BasisSurface : IfcPlane; OuterBoundary : IfcCurve; InnerBoundaries : SET [0:?] OF IfcCurve; END_ENTITY;