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8.9.3.28 IfcCurveSegment

AbV ⓘ

8.9.3.28.1 Semantic definition

A type of segment positioned along a curve cutting a segment from the parent curve. If the segment is placed through IfcAxis2PlacementLinear, the positioning curve (Placement.Location.BasisCurve) does not necessarily correspond with the ParentCurve.

Informal Propositions

  1. For the foreseeable future, until implementer agreements have resulted in a defined parametric space for all possible types in attribute ParentCurve, the values for attributes SegmentStart and SegmentStart shall be of type IfcLengthMeasure.

8.9.3.28.2 Entity inheritance

8.9.3.28.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
IfcSegment (3)
Click to show 5 hidden inherited attributes
IfcCurveSegment (4)
2 Placement IfcPlacement

Placement in the context of the curve using this segment. As insertion point SegmentStart is the reference point of Placement. RefDirection of Placement also specifies the sense of the trimmed segment of ParentCurve. RefDirection is bound to the parametrization sense of the segment.

3 SegmentStart IfcCurveMeasureSelect

First trimming point of the curve segment on the ParentCurve. This point is used as the insertion point into the segmented, gradient or composite curve using this segment.

4 SegmentLength IfcCurveMeasureSelect

Length of segment measured as length or parameter value from SegmentStart. The sign of this value defines the sense agreement.

5 ParentCurve IfcCurve

Curve to be used as base for the segment definition.

Table 8.9.3.28.D

8.9.3.28.4 Examples

8.9.3.28.5 Formal representation

ENTITY IfcCurveSegment
SUBTYPE OF (IfcSegment);
Placement : IfcPlacement;
SegmentStart : IfcCurveMeasureSelect;
SegmentLength : IfcCurveMeasureSelect;
ParentCurve : IfcCurve;
END_ENTITY;

8.9.3.28.6 References

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8.9.3.28.7 Changelog

8.9.3.28.7.1 IFC4.3_DEV_738df036

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