Navigation

IfcCurve

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 class in IFC Release 1.0

Informal proposition:

  1. A curve shall be arwise connected
  2. A curve shall have an arc length greater than zero.

EXPRESS specification:

ENTITY IfcCurve
ABSTRACT SUPERTYPE OF (ONEOF(IfcBoundedCurve, IfcConic, IfcLine, IfcOffsetCurve2D, IfcOffsetCurve3D))
SUBTYPE OF ( IfcGeometricRepresentationItem);
DERIVE
Dim  :  IfcDimensionCount :=  IfcCurveDim(SELF);
END_ENTITY;

Attribute definitions:

Dim  :  The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.

References (10):

Name Type Referred through Express-G
IfcBoundedCurve Entity
Supertype
Diagram 5
IfcCompositeCurveSegment Entity
Attribute 'ParentCurve'
Diagram 6
IfcConic Entity
Supertype
Diagram 5
IfcGeometricRepresentationItem Entity
Subtype
Diagram 1
IfcLine Entity
Supertype
Diagram 5
IfcOffsetCurve2D Entity
Supertype
Attribute 'BasisCurve'
Diagram 5
IfcOffsetCurve3D Entity
Supertype
Attribute 'BasisCurve'
Diagram 5
IfcTrimmedCurve Entity
Attribute 'BasisCurve'
Diagram 6

Inheritance graph

ENTITY IfcCurve;
ENTITY IfcCurve;
DERIVE
Dim  :  IfcDimensionCount :=  IfcCurveDim(SELF);
END_ENTITY;