 | Offset Curve By Distances |
| Item | SPF | XML | Change | Description | IFC4x1 Release Candidate 3 |
|---|---|---|---|---|
| IfcOffsetCurveByDistances | ADDED |
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 374 illustrates eight instances of IfcOffsetCurveByDistances (in green) defined relative to an IfcAlignmentCurve (in blue).
 |
Figure 374 — Offset curve by distances |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| 2 | OffsetValues | IfcDistanceExpression | L[1:?] | 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. | X |
| 3 | Tag | IfcLabel | ? | Optional identifier of the curve, which may be used to correlate points from a variable cross-section. | X |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcRepresentationItem | |||||
| LayerAssignment | IfcPresentationLayerAssignment @AssignedItems | S[0:1] | 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. | X | |
| StyledByItem | IfcStyledItem @Item | S[0:1] | 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. | X | |
| IfcGeometricRepresentationItem | |||||
| IfcCurve | |||||
| Dim :=IfcCurveDim(SELF) | IfcDimensionCount | The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. | X | ||
| IfcOffsetCurve | |||||
| 1 | BasisCurve | IfcCurve | The curve that is being offset. | X | |
| IfcOffsetCurveByDistances | |||||
| 2 | OffsetValues | IfcDistanceExpression | L[1:?] | 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. | X |
| 3 | Tag | IfcLabel | ? | Optional identifier of the curve, which may be used to correlate points from a variable cross-section. | X |
<xs:element name="IfcOffsetCurveByDistances" type="ifc:IfcOffsetCurveByDistances" substitutionGroup="ifc:IfcOffsetCurve" nillable="true"/>
<xs:complexType name="IfcOffsetCurveByDistances">
<xs:complexContent>
<xs:extension base="ifc:IfcOffsetCurve">
<xs:sequence>
<xs:element name="OffsetValues">
<xs:complexType>
<xs:sequence>
<xs:element ref="ifc:IfcDistanceExpression" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcDistanceExpression"/>
<xs:attribute ref="ifc:cType" fixed="list"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attribute name="Tag" type="ifc:IfcLabel" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
ENTITY IfcOffsetCurveByDistances
SUBTYPE OF (IfcOffsetCurve);
OffsetValues : LIST [1:?] OF IfcDistanceExpression;
Tag : OPTIONAL IfcLabel;
END_ENTITY;
EXPRESS-G diagram
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