#### IfcCurve

Natural language names

##### 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:

1. A curve shall be arcwise connected
2. 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

`

Link to this page