IFC 4.3.x development

8.9.3.57 IfcReparametrisedCompositeCurveSegment

Change log

IFC4

added

8.9.3.57.1 Semantic definitions at the entity

The IfcReparametrisedCompositeCurveSegment is geometrically identical to a IfcCompositeCurveSegment but with the additional capability of reparametrization.

NOTE  Definition according to ISO/CD 10303-42:1992
The reparametrised composite curve segment is a special type of composite curve segment which provides the capability to re-define its parametric length without changing its geometry.

If t~0~ ≤ t ≤ t~1~ is the parameter range of ParentCurve, the new parameter . for the reparametrised composite curve segment is given by the equation:

Image if SameSense = TRUE; or by the equation:

Image if SameSense = FALSE;

NOTE  Entity adapted from reparametrised_composite_curve_segment in ISO 10303-42.

HISTORY  New entity in IFC4

8.9.3.57.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item 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.
IfcGeometricRepresentationItem
IfcSegment
1 Transition IfcTransitionCode Connectivity between the continuous segments is not enforced per se to be tangential. Setting "TangentialContinuity" to True means that the current segment shall continue with tangential continuity to the previous one.
UsingCurves SET [1:?] OF IfcCompositeCurve FOR Segments The set of composite curves which use this composite curve segment as a segment. This set shall not be empty.
IfcCompositeCurveSegment
2 SameSense IfcBoolean An indicator of whether or not the sense of the segment agrees with, or opposes, that of the parent curve. If SameSense is false, the point with highest parameter value is taken as the first point of the segment.

> NOTE  If the datatype of ParentCurve is IfcTrimmedCurve, the value of SameSense overrides the value of _IfcTrimmedCurve.SenseAgreement_
3 ParentCurve IfcCurve The bounded curve which defines the geometry of the segment.
Dim INVALID The space dimensionality of this class, defined by the dimensionality of the first ParentCurve.
IfcReparametrisedCompositeCurveSegment
4 ParamLength IfcParameterValue

8.9.3.57.2 Entity inheritance

dot_inheritance IfcReparametrisedCompositeCurveSegment IfcReparametrisedCompositeCurveSegment IfcCompositeCurveSegment IfcCompositeCurveSegment IfcReparametrisedCompositeCurveSegment->IfcCompositeCurveSegment IfcSegment IfcSegment IfcCompositeCurveSegment->IfcSegment IfcCurveSegment IfcCurveSegment IfcCurveSegment->IfcSegment IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcSegment->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.57.3 Formal representations

ENTITY IfcReparametrisedCompositeCurveSegment
 SUBTYPE OF (IfcCompositeCurveSegment);
	ParamLength : IfcParameterValue;
 WHERE
	PositiveLengthParameter : ParamLength > 0.0;
END_ENTITY;