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8.9.3.38 IfcMappedItem

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8.9.3.38.1 Semantic definition

The IfcMappedItem is the inserted instance of a source definition (to be compared with a block / shared cell / macro definition). The instance is inserted by applying a Cartesian transformation operator as the MappingTarget.

A mapped item is a subtype of representation item. It enables a representation to be used as a representation item in one or more other representations. The mapped item allows for the definition of a representation using other representations. An IfcMappedItem can reuse other mapped items (ako nested blocks), doing so the IfcRepresentationMap is based on an IfcShapeRepresentation including one or more IfcMappedItem's. Definition according to ISO/CD 10303-43:1992 A mapped item is a type of representation item that specifies the mapping of a representation as an element of the items of a second representation. Entity adapted from mapped_item defined in ISO 10303-43. New entity in IFC2x.

Informal Propositions

  1. A mapped item shall not be self-defining by participating in the definition of the representation being mapped.
  2. The dimensionality of the mapping source and the mapping target has to be the same, if the mapping source is a geometric representation item.

8.9.3.38.2 Entity inheritance

8.9.3.38.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

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.

The inverse attribute LayerAssignments has been added. 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.

The inverse attribute StyledByItem has been added.
Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes
IfcMappedItem (2)
1 MappingSource IfcRepresentationMap

A representation map that is the source of the mapped item. It can be seen as a block (or cell or marco) definition.

2 MappingTarget IfcCartesianTransformationOperator

A representation item that is the target onto which the mapping source is mapped. It is constraint to be a Cartesian transformation operator.

Table 8.9.3.38.K

8.9.3.38.4 Examples

8.9.3.38.5 Formal representation

ENTITY IfcMappedItem
 SUBTYPE OF (IfcRepresentationItem);
	MappingSource : IfcRepresentationMap;
	MappingTarget : IfcCartesianTransformationOperator;
END_ENTITY;

8.9.3.38.6 References

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