IfcPlacement

BACnet MVD

#### IfcPlacement

Natural language names

| Positionierung
| Placement
| Positionnement

##### Semantic definitions at the entity

Entity definition

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

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | Location | IfcCartesianPoint |  | The geometric position of a reference point, such as the center of a circle, of the item to be located. | X | X
| Dim :=Location.Dim | IfcDimensionCount |  | The space dimensionality of this class, derived from the dimensionality of the location. | X | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRepresentationItem

LayerAssignment

IfcPresentationLayerAssignment
@AssignedItems

S[0:1]

Assignment 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.

X

StyledByItem

IfcStyledItem
@Item

S[0:1]

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.

X

X

IfcGeometricRepresentationItem
IfcPlacement
1 | Location | IfcCartesianPoint |  | The geometric position of a reference point, such as the center of a circle, of the item to be located. | X | X
| Dim :=Location.Dim | IfcDimensionCount |  | The space dimensionality of this class, derived from the dimensionality of the location. | X | X

##### Formal representations

XML Specification
`<xs:element name="IfcPlacement" type="ifc:IfcPlacement" abstract="true" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>
<xs:complexType name="IfcPlacement" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcGeometricRepresentationItem">
<xs:sequence>
<xs:element name="Location" type="ifc:IfcCartesianPoint" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPlacement
ABSTRACT SUPERTYPE OF(ONEOF(IfcAxis1Placement, IfcAxis2Placement2D, IfcAxis2Placement3D))
SUBTYPE OF (IfcGeometricRepresentationItem);
Location : IfcCartesianPoint;
DERIVE
Dim : IfcDimensionCount := Location.Dim;
END_ENTITY;

EXPRESS-G diagram

`

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