IfcCurve

Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-42:1992: A curve can be envisioned as the path of a point moving in its coordinate space.

NOTE: Corresponding STEP entity: curve, only the following subtypes have been incorporated into IFC: line as IfcLine, conic as IfcConic, bounded_curve as IfcBoundedCurve. Please refer to ISO/IS 10303-42:1994, p.37 for the final definition of the formal standard. The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem).

HISTORY: New entity in IFC Release 1.0

Informal proposition:

A curve shall be arcwise connected
A curve shall have an arc length greater than zero.

Attribute definitions

#	Attribute	Type	Cardinality	Description	A
	Dim :=IfcCurveDim(SELF)	IfcDimensionCount	[1:1]	The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	A
IfcRepresentationItem
IfcGeometricRepresentationItem
IfcCurve
	Dim :=IfcCurveDim(SELF)	IfcDimensionCount	[1:1]	The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.	X

Formal representations

XSD Specification

 <xs:element name="IfcCurve" type="ifc:IfcCurve" abstract="true" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>

 <xs:complexType name="IfcCurve" abstract="true">

  <xs:complexContent>

   <xs:extension base="ifc:IfcGeometricRepresentationItem"/>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcCurve

 ABSTRACT SUPERTYPE OF(ONEOF(IfcBoundedCurve, IfcConic, IfcLine))

 SUBTYPE OF (IfcGeometricRepresentationItem);

 DERIVE

  Dim : IfcDimensionCount := IfcCurveDim(SELF);

END_ENTITY;

 EXPRESS-G diagram