IFC 4.3.x development

8.14.3.9 IfcPresentationLayerAssignment

Change log

IFC4

additionswhere_rulesApplicableItems

IFC4X1

additionswhere_rulesApplicableItems
deletionswhere_rulesApplicableItems

IFC4X2

additionswhere_rulesApplicableItems
deletionswhere_rulesApplicableItems

IFC4X3_RC3

additionswhere_rulesApplicableItems
deletionswhere_rulesApplicableItems

8.14.3.9.1 Semantic definitions at the entity

The presentation layer assignment provides the layer name (and optionally a description and an identifier) for a collection of geometric representation items. The IfcPresentationLayerAssignment corresponds to the term "CAD Layer" and is used mainly for grouping and visibility control.

NOTE  The use of presentation layer shall be restricted to simple grouping and displaying purposes.

Visibility and access control and layer style assignment (colour, line style, line width) is handled by the subtype IfcPresentationLayerAssignmentWithStyle.

NOTE  Corresponding ISO 10303 name: presentation layer assignment. Please refer to ISO/IS 10303-46:1994, p. 36 for the final definition of the formal standard.

HISTORY  New entity in IFC2x2.

Attribute use definition

Figure 1 illustrates assignment of items by shape representation or representation item. The set of AssignedItems can either include a whole shape representation, or individual geometric representation items. If both, the IfcShapeRepresentation has a layer assignment, and an individual geometric representation item in the set of IfcShapeRepresentation.Items, then the layer assignment of the IfcGeometricRepresentationItem overides the layer assignment of the IfcShapeRepresentation.

"instantiation diagram"

8.14.3.9.1 Attributes

#Attribute Type Description
IfcPresentationLayerAssignment
1Name IfcLabel Name of the layer.
2Description OPTIONAL IfcText Additional description of the layer.
3AssignedItemsSET [1:?] OF IfcLayeredItemThe set of layered items, which are assigned to this layer.
4Identifier OPTIONAL IfcIdentifier An (internal) identifier assigned to the layer.

8.14.3.9.2 Entity inheritance

dot_inheritance IfcPresentationLayerWithStyle IfcPresentationLayerWithStyle IfcPresentationLayerAssignment IfcPresentationLayerAssignment IfcPresentationLayerWithStyle->IfcPresentationLayerAssignment

8.14.3.9.3 Formal representations

ENTITY IfcPresentationLayerAssignment
 SUPERTYPE OF (ONEOF
	(IfcPresentationLayerWithStyle));
	Name : IfcLabel;
	Description : OPTIONAL IfcText;
	AssignedItems : SET [1:?] OF IfcLayeredItem;
	Identifier : OPTIONAL IfcIdentifier;
 WHERE
	ApplicableItems : SIZEOF(QUERY(temp <* AssignedItems | (
  SIZEOF(TYPEOF(temp) * [
    'IFC4X3_DEV_a1492713.IFCSHAPEREPRESENTATION',
    'IFC4X3_DEV_a1492713.IFCGEOMETRICREPRESENTATIONITEM',
    'IFC4X3_DEV_a1492713.IFCMAPPEDITEM']) = 1)
)) = SIZEOF(AssignedItems);
END_ENTITY;