8.7.3.15 IfcObjectPlacement
ABSTRACT This definition may not be instantiated
8.7.3.15.1 Semantic definition
IfcObjectPlacement is an abstract supertype for the special types defining the object coordinate system. The IfcObjectPlacement has to be provided for each product that has a shape representation.
The object placement can be given:
- absolute: by an axis2 placement, relative to the world coordinate system,
- relative: by an axis2 placement, relative to the object placement of another product,
- by grid reference: by the virtual intersection and reference direction given by two axes of a design grid,
- linear placement: by distance along a curve, with possible offsets.
In any case the object placement has to unambiguously define the object coordinate system as either two-dimensional axis placement (IfcAxis2Placement2D) or three-dimensional axis placement (IfcAxis2Placement3D). The axis placement may have to be calculated.
8.7.3.15.2 Entity inheritance
8.7.3.15.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcObjectPlacement (3) | |||
| 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. |
| PlacesObject | SET [0:?] OF IfcProduct FOR ObjectPlacement |
The IfcObjectPlacement shall be used to provide a placement and an object coordinate system for instances of IfcProduct. |
|
| ReferencedByPlacements | SET [0:?] OF IfcObjectPlacement FOR PlacementRelTo |
No description available. |
|
8.7.3.15.4 Formal representation
ENTITY IfcObjectPlacement
ABSTRACT SUPERTYPE OF (ONEOF
(IfcGridPlacement
,IfcLinearPlacement
,IfcLocalPlacement));
PlacementRelTo : OPTIONAL IfcObjectPlacement;
INVERSE
PlacesObject : SET [0:?] OF IfcProduct FOR ObjectPlacement;
ReferencedByPlacements : SET [0:?] OF IfcObjectPlacement FOR PlacementRelTo;
END_ENTITY;