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IfcCurveBoundedPlane

Definition from ISO/CD 10303-42:1992: The curve bounded surface is a parametric surface with curved boundaries defined by one or more boundary curves. The bounded surface 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.

Definition from IAI: The IfcCurveBoundedPlane is a specialized bounded surface class that deals only with bounding basis plane surfaces. The definition varies from STEP as outer and inner boundaries are separated attributes and reference the special IFC type Ifc2DCompositeCurve. Only basis surfaces of type IfcPlane are allowed, and the implicit_outer attribute has not been incorporated, since only unbounded surfaces are used as basis surface.

NOTE After the enhancement of the profile definition capacities in IFC Release 2.x this entity is not needed anymore for the definition of boundaries on a plane for the purpose of swept area solids. Therefore this entity is marked as depreciated - that means it will not be supported in future versions of IFC.

NOTE Corresponding STEP entity curve_bounded_surface has been changed to meet the specific requirements of an easy representation of curve bounded planes.

HISTORY New class in IFC Release 1.5
ISSUE: See issue log for changes made in IFC Release 1.5.1


EXPRESS specification:

ENTITY IfcCurveBoundedPlane
SUBTYPE OF ( IfcBoundedSurface);
BasisSurface  :  IfcPlane;
OuterBoundary  :  Ifc2DCompositeCurve;
InnerBoundaries  :  SET OF Ifc2DCompositeCurve;
DERIVE
Dim  :  IfcDimensionCount :=  BasisSurface.Dim;
END_ENTITY;

Attribute definitions:

BasisSurface  :  The surface to be bound.
OuterBoundary  :  The outer boundary of the surface.
InnerBoundaries  :  An optional set of inner boundaries. They shall not intersect each other or the outer boundary.
Dim  :  The space dimensionality of this class, defined by the dimensionality of the basis surface.

References (1):

Name Type Referred through Express-G
IfcBoundedSurface Entity
Subtype
Diagram 7

Inheritance graph

ENTITY IfcCurveBoundedPlane;
ENTITY IfcRepresentationItem;
ENTITY IfcGeometricRepresentationItem;
ENTITY IfcSurface;
ENTITY IfcBoundedSurface;
ENTITY IfcCurveBoundedPlane;
BasisSurface  :  IfcPlane;
OuterBoundary  :  Ifc2DCompositeCurve;
InnerBoundaries  :  SET OF Ifc2DCompositeCurve;
DERIVE
Dim  :  IfcDimensionCount :=  BasisSurface.Dim;
END_ENTITY;