IfcCurve

Semantic definitions at the entity

Entity definition

An IfcCurve is a curve in two-dimensional or three-dimensional space. It includes definitions for bounded and unbounded curves.

NOTE Definition according to ISO 10303-42:
A curve can be envisioned as the path of a point moving in its coordinate space.

NOTE Entity adapted from curve defined in ISO 10303-42

HISTORY New entity in IFC1.0

Informal Propositions:

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

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
	Dim :=IfcCurveDim(SELF)	IfcDimensionCount		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	G
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @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
	StyledByItem	IfcStyledItem @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)	IfcDimensionCount		The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.	X

Formal representations

XML 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, IfcOffsetCurve, IfcPcurve, IfcPolynomialCurve, IfcSpiral, IfcSurfaceCurve))

 SUBTYPE OF (IfcGeometricRepresentationItem);

 DERIVE

  Dim : IfcDimensionCount := IfcCurveDim(SELF);

END_ENTITY;

 EXPRESS-G diagram

	Kurve
	Curve
	Courbe