IFC 4.3.x development

8.7.3.13 IfcLinearPlacement

Change log

IFC4X1

added

IFC4X2

modificationsattributes PlacementRelTo nameChanged from PlacementRelTo to PlacementMeasuredAlong

IFC4X3_RC3

deletions attributes Distance
deletions attributes Orientation
modificationsattributes PlacementMeasuredAlong definitionChanged from IfcCurve to IfcAxis2PlacementLinear
modificationsattributes PlacementMeasuredAlong name Changed from PlacementMeasuredAlong to RelativePlacement

8.7.3.13.1 Semantic definitions at the entity

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.

8.7.3.13.1 Attributes

# Attribute Type Description
IfcObjectPlacement
PlacesObject SET [0:?] OF IfcProduct FOR ObjectPlacementThe 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 CHANGEĀ  New inverse attribute.

> IFC4 CHANGEĀ  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.
1 PlacementRelTo OPTIONAL 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.
IfcLinearPlacement
2 RelativePlacementIfcAxis2PlacementLinear
3 CartesianPositionOPTIONAL IfcAxis2Placement3D

8.7.3.13.2 Entity inheritance

dot_inheritance IfcLinearPlacement IfcLinearPlacement IfcObjectPlacement IfcObjectPlacement IfcLinearPlacement->IfcObjectPlacement IfcGridPlacement IfcGridPlacement IfcGridPlacement->IfcObjectPlacement IfcLocalPlacement IfcLocalPlacement IfcLocalPlacement->IfcObjectPlacement

8.7.3.13.3 Formal representations

ENTITY IfcLinearPlacement
 SUBTYPE OF (IfcObjectPlacement);
	RelativePlacement : IfcAxis2PlacementLinear;
	CartesianPosition : OPTIONAL IfcAxis2Placement3D;
END_ENTITY;