IFC 4.3.x development

8.9.3.46 IfcPlacement

Change log

IFC4X3_RC3

modificationsattributes Location definitionChanged from IfcCartesianPoint to IfcPoint

8.9.3.46.1 Semantic definitions at the entity

An IfcPlacement is an abstract supertype of placement subtypes that define the location of an item, or an entire shape representation, and provide its orientation. All placement subtypes define right-handed Cartesian coordinate systems and do not allow mirroring.

NOTE  Cartesian transformations including mirroring and scaling are supported by IfcCartesianTransformationOperator

NOTE  Definition according to ISO/CD 10303-42:1992
A placement locates a geometric item with respect to the coordinate system of its geometric context. It locates the item to be defined and, in the case of the axis placement subtypes, gives its orientation.

NOTE  Entity adapted from placement defined in ISO 10303-42.

HISTORY  New entity in IFC1.0

8.9.3.46.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item 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.
IfcGeometricRepresentationItem
IfcPlacement
1 Location IfcPoint The geometric position of a reference point, such as the center of a circle, of the item to be located.
Dim INVALID The space dimensionality of this class, derived from the dimensionality of the location.

8.9.3.46.2 Entity inheritance

dot_inheritance IfcPlacement_children 3 more... IfcPlacement IfcPlacement IfcPlacement_children->IfcPlacement IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcPlacement->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.46.3 Formal representations

ENTITY IfcPlacement
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcAxis1Placement
	,IfcAxis2Placement2D
	,IfcAxis2Placement3D
	,IfcAxis2PlacementLinear))
 SUBTYPE OF (IfcGeometricRepresentationItem);
	Location : IfcPoint;
 DERIVE
	 Dim : IfcDimensionCount := Location.Dim;
END_ENTITY;