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Ifc2DCompositeCurve

Definition from IAI: An Ifc2DCompositeCurve is an IfcCompositeCurve that is defined within the coordinate space of an IfcPlane. Therefore the dimensionality of the Ifc2DCompositeCurve has to be 2.

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. Therefore this entity is marked as depreciated - that means it will not be supported in future versions of IFC.

NOTE This entity has been introduced to get a more straight forward definition of surface boundaries than by its counterpart in STEP: composite_curve_on_surface and boundary_curve. Since the only basis elementary surface in IFC is the plane surface, a two dimensional composite curve provides enough capability to define the boundary.

HISTORY New class in IFC Release 1.5


EXPRESS specification:

ENTITY Ifc2DCompositeCurve
SUBTYPE OF ( IfcCompositeCurve);
WHERE
WR1  :  SELF\IfcCompositeCurve.ClosedCurve;
WR2  :  SELF\IfcCurve.Dim = 2;
END_ENTITY;

Formal Propositions:

WR1  :  The composite curve shall be closed.
WR2  :  The dimensionality of the composite curve shall be 2

References (3):

Name Type Referred through Express-G
IfcCompositeCurve Entity
Subtype
Diagram 6
IfcCurveBoundedPlane Entity
Attribute 'OuterBoundary'
Attribute 'InnerBoundaries'
Diagram 7

Inheritance graph

ENTITY Ifc2DCompositeCurve;
ENTITY IfcCurve;
DERIVE
Dim  :  IfcDimensionCount :=  IfcCurveDim(SELF);
ENTITY IfcCompositeCurve;
Segments  :  LIST [1:?] OF IfcCompositeCurveSegment;
SelfIntersect  :  LOGICAL;
DERIVE
NSegments  :  INTEGER :=  SIZEOF(Segments);
ClosedCurve  :  LOGICAL :=  Segments[NSegments].Transition <> Discontinuous;
END_ENTITY;