8.9.3.42 IfcOffsetCurveByDistances

8.9.3.42.1 Semantic definition

An IfcOffsetCurveByDistances is a curve defined by a list of offsets along its BasisCurve. If only one offset is provided, it indicates a constant offset along the extents of the basis curve.

Figure 8.9.3.42.A illustrates eight instances of IfcOffsetCurveByDistances (in green) defined relative to an IfcGradientCurve (in blue).

spatial structure — Figure 8.9.3.42.A — Offset curve by distances

8.9.3.42.2 Entity inheritance

8.9.3.42.3 Attributes

#	Attribute	Type	Description
IfcRepresentationItem (2)
	LayerAssignment	SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems	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.
	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.
IfcCurve (1)
*	Dim	IfcDimensionCount	This attribute is formally derived. `IfcCurveDim(SELF)` The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.
IfcOffsetCurve (1)
1	BasisCurve	IfcCurve	The curve that is being offset.
Click to show 4 hidden inherited attributes
IfcOffsetCurveByDistances (2)
2	OffsetValues	LIST [1:?] OF IfcPointByDistanceExpression	List of sequential points described relative to the basis curve. If the offsets do not span the full extent of the basis curve (e.g. if the list contains only one item), then the lateral and vertical offsets implicitly continue with the same value towards the head and tail of the basis curve.
3	Tag	OPTIONAL IfcLabel	Optional identifier of the curve, which may be used to correlate points from a variable cross-section.

Table 8.9.3.42.C

8.9.3.42.4 Formal representation

 ENTITY IfcOffsetCurveByDistances
 SUBTYPE OF (IfcOffsetCurve);
	OffsetValues : LIST [1:?] OF IfcPointByDistanceExpression;
	Tag : OPTIONAL IfcLabel;
END_ENTITY;

8.9.3.42.5 References

IfcOffsetCurve