IfcBoundaryCurve

Natural language names
Begrenzungskurve
Boundary Curve
Courbe limite
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcBoundaryCurveADDED
IFC4 Addendum 1
    IfcBoundaryCurve
      SelfIntersectMODIFIEDType changed from LOGICAL to IfcLogical.
Semantic definitions at the entity
Entity definition

An IfcBoundaryCurve defines a curve acting as the boundary of a surface.

NOTE  Definition according to ISO/CD 10303-42:1992
A boundary curve is a type of bounded curve suitable for the definition of a surface boundary.
NOTE  Entity adapted from boundary_curve defined in ISO10303-42.
HISTORY  New entity in IFC4.
Formal Propositions
RuleDescription
IsClosedThe derived ClosedCurve attribute of IfcCompositeCurve supertype shall be TRUE.
Inherited definitions from supertypes
Entity inheritance IfcOuterBoundaryCurve IfcCompositeCurveOnSurface IfcCompositeCurve IfcBoundedCurve IfcCurve IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@AssignedItems
S[0:1]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.
X
StyledByItemIfcStyledItem
@Item
S[0:1]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.
X
IfcGeometricRepresentationItem
IfcCurve
Dim
:=IfcCurveDim(SELF)
IfcDimensionCountThe space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. X
IfcBoundedCurve
IfcCompositeCurve
1SegmentsIfcCompositeCurveSegmentL[1:?] The component bounded curves, their transitions and senses. The transition attribute for the last segment defines the transition between the end of the last segment and the start of the first; this transition attribute may take the value discontinuous, which indicates an open curve. X
2SelfIntersectIfcLogical Indication of whether the curve intersects itself or not; this is for information only. X
NSegments
:=SIZEOF(Segments)
IfcIntegerThe number of component curves. X
ClosedCurve
:=Segments[NSegments].Transition <> Discontinuous
IfcLogicalIndication whether the curve is closed or not; this is derived from the transition code of the last segment. X
IfcCompositeCurveOnSurface
BasisSurface
:=IfcGetBasisSurface(SELF)
IfcSurfaceS[0:1]The surface on which the composite curve is defined. X
IfcBoundaryCurve
Formal representations
XML Specification
 <xs:element name="IfcBoundaryCurve" type="ifc:IfcBoundaryCurve" substitutionGroup="ifc:IfcCompositeCurveOnSurface" nillable="true"/>
 <xs:complexType name="IfcBoundaryCurve">
  <xs:complexContent>
   <xs:extension base="ifc:IfcCompositeCurveOnSurface"/>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcBoundaryCurve
 SUPERTYPE OF(IfcOuterBoundaryCurve)
 SUBTYPE OF (IfcCompositeCurveOnSurface);
 WHERE
  IsClosed : SELF\IfcCompositeCurve.ClosedCurve;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcCurveBoundedSurface

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