IfcObjectPlacement

Natural language names
Objektpositionierung
Object Placement
Positionnement d'objet
Semantic definitions at the entity
Entity 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:

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.

HISTORY  New entity in IFC2x.
Attribute definitions
#AttributeTypeCardinalityDescription G
1PlacementRelToIfcObjectPlacement? 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
PlacesObjectIfcProduct
@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
Inherited definitions from supertypes
Entity inheritance IfcGridPlacement IfcLinearPlacement IfcLocalPlacement
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcObjectPlacement
1PlacementRelToIfcObjectPlacement? 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
PlacesObjectIfcProduct
@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
Formal representations
XML Specification
 <xs:element name="IfcObjectPlacement" type="ifc:IfcObjectPlacement" abstract="true" substitutionGroup="ifc:Entity" nillable="true"/>
 <xs:complexType name="IfcObjectPlacement" abstract="true">
  <xs:complexContent>
   <xs:extension base="ifc:Entity">
    <xs:sequence>
     <xs:element name="PlacementRelTo" type="ifc:IfcObjectPlacement" nillable="true" minOccurs="0"/>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcObjectPlacement
 ABSTRACT SUPERTYPE OF(ONEOF(IfcGridPlacement, IfcLinearPlacement, IfcLocalPlacement));
  PlacementRelTo : OPTIONAL IfcObjectPlacement;
 INVERSE
  PlacesObject : SET [0:?] OF IfcProduct FOR ObjectPlacement;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcProduct IfcStructuralAnalysisModel IfcObjectPlacement

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