 | Linear Placement |
| Item | SPF | XML | Change | Description | IFC4x1 Final 4.1.0.0 |
|---|---|---|---|---|
| IfcLinearPlacement | ADDED | IFC4x2 Candidate 4.2.0.0 | ||
| IfcLinearPlacement | ||||
| PlacementRelTo | X | X | MODIFIED | Type changed from IfcCurve to IfcObjectPlacement. Instantiation changed to OPTIONAL. |
| PlacementMeasuredAlong | X | X | MODIFIED | Name changed from Distance to PlacementMeasuredAlong. Type changed from IfcDistanceExpression to IfcCurve. |
| Distance | X | X | MODIFIED | Name changed from Orientation to Distance. Type changed from IfcOrientationExpression to IfcDistanceExpression. Instantiation changed from OPTIONAL. |
| Orientation | X | X | MODIFIED | Name changed from CartesianPosition to Orientation. Type changed from IfcAxis2Placement3D to IfcOrientationExpression. |
| CartesianPosition | ADDED | |||
| ReferencedByPlacements | DELETED | IFC4x3_RC1 to IFC4x3_RC2 | ||
| IfcLinearPlacement | ||||
| PlacementMeasuredAlong | MODIFIED | Status changed to Deprecated. | ||
| Distance | X | X | MODIFIED | Status changed to Deprecated. Type changed from IfcDistanceExpression to IfcPointByDistanceExpression. |
| RelativePlacement | X | X | MODIFIED | Name changed from Orientation to RelativePlacement. Type changed from IfcOrientationExpression to IfcAxis2PlacementLinear. Instantiation changed from OPTIONAL. | IFC4x3_RC2 to IFC4x3_RC3 |
| IfcLinearPlacement | ||||
| RelativePlacement | X | X | MODIFIED | Name changed from PlacementMeasuredAlong to RelativePlacement. Status changed from Deprecated. Type changed from IfcCurve to IfcAxis2PlacementLinear. |
| CartesianPosition | X | X | MODIFIED | Name changed from Distance to CartesianPosition. Status changed from Deprecated. Type changed from IfcPointByDistanceExpression to IfcAxis2Placement3D. Instantiation changed to OPTIONAL. |
| RelativePlacement | X | DELETED | ||
| CartesianPosition | X | DELETED |
IfcLinearPlacement provides a specialization of IfcObjectPlacement in which the placement and axis direction of the object coordinate system is defined by a reference to a curve. RelativePlacement is therefore restricted to IfcAxis2PlacementLinear.
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| 2 | RelativePlacement | IfcAxis2PlacementLinear | X | ||
| 3 | CartesianPosition | IfcAxis2Placement3D | ? | X |
| Rule | Description |
|---|---|
| CorrectLinearPlacement | A linear placement is always relative to a local placement which sets the georeferencing context i. e. provide the indirect reference to IfcProject with assigned Project Global Positioning.
HISTORY: New in IFC4.4. |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcObjectPlacement | |||||
| 1 | PlacementRelTo | IfcObjectPlacement | ? | Reference to object placement that provides the relative placement with its placement in a grid, local coordinate system or linear referenced placement. If it is omitted, then in the case of linear placement it is established by the origin of horizontal alignment of the referenced IfcAlignment Axis. In the case of local placement it is established by the geometric representation context. | X |
| PlacesObject | IfcProduct @ObjectPlacement | S[0:?] | The IfcObjectPlacement shall be used to provide a placement and
an object coordinate system for instances of IfcProduct.
If an IfcObjectPlacement is shared by many instances of IfcProduct it does not apply a semantic meaning of being a shared placement that needs to be maintained. The same instance of IfcObjectPlacement could simply be used to reduce exchange file size. IFC2x3 CHANGE New inverse attribute. IFC4 CHANGE The cardinality has changed to 0..n to allow reuse of instances of IfcObjectPlacement as placement object in one to many products. It takes also into account that it can act as a placement for IfcStructuralAnalysisModel. | X | |
| ReferencedByPlacements | IfcObjectPlacement @PlacementRelTo | S[0:?] | Placements that are given relative to this placement of an object. | X | |
| IfcLinearPlacement | |||||
| 2 | RelativePlacement | IfcAxis2PlacementLinear | X | ||
| 3 | CartesianPosition | IfcAxis2Placement3D | ? | X | |
<xs:element name="IfcLinearPlacement" type="ifc:IfcLinearPlacement" substitutionGroup="ifc:IfcObjectPlacement" nillable="true"/>
<xs:complexType name="IfcLinearPlacement">
<xs:complexContent>
<xs:extension base="ifc:IfcObjectPlacement">
<xs:sequence>
<xs:element name="RelativePlacement" type="ifc:IfcAxis2PlacementLinear" nillable="true"/>
<xs:element name="CartesianPosition" type="ifc:IfcAxis2Placement3D" nillable="true" minOccurs="0"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
ENTITY IfcLinearPlacement
SUBTYPE OF (IfcObjectPlacement);
RelativePlacement : IfcAxis2PlacementLinear;
CartesianPosition : OPTIONAL IfcAxis2Placement3D;
WHERE
CorrectLinearPlacement : EXISTS(SELF\IfcObjectPlacement.PlacementRelTo) AND ('IFCGEOMETRICCONSTRAINTRESOURCE.IfcLocalPlacement' IN TYPEOF(SELF\IfcObjectPlacement.PlacementRelTo));
END_ENTITY;
EXPRESS-G diagram
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