IfcBuildingElementProxy

Definition from IAI: The IfcBuildingElementProxy is a proxy definition that provides the same functionality as an IfcBuildingElement, but without having a defined meaning of the special type of building element, it represents.

> NOTE1 The IfcBuildingElementProxy should be used to exchange special types of building elements for which the current IFC Release does not yet provide a semantic definition.

> NOTE2 The IfcBuildingElementProxy can also be used to represent building elements for which the participating applications can not provide additional semantic classification.

> HISTORY New entity in IFC Release 2x.

Type Use Definition

The IfcBuildingElementProxy defines the occurrence of any building element, common information about the types (or styles) is handled by IfcBuildingElementProxyType.

The IfcBuildingElementProxyType (if present) may establish the common type name, usage (or predefined) type, common material, common set of properties and common shape representations (using IfcRepresentationMap). The IfcBuildingElementProxyType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsDefinedBy attribute.

> NOTE The IfcBuildingElementProxyType can be used to share common information among many occurrences of the same proxy without establishing a particular semantic meaning of the type.

If no IfcBuildingElementProxyType is attached (i.e. if only occurrence information is given) the predefined type may be given by using the ObjectType attribute.

Property Set Use Definition:

The property sets relating to the IfcBuildingElementProxy are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBuildingElementProxy/i> are part of this IFC release:

- Pset_BuildingElementProxyCommon: common property set for all occurrences of building element proxies.

Geometry Use Definitions

The geometric representation of any IfcBuildingElementProxy is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. The representation types defined at the supertype IfcBuildingElement also apply.

Local Placement

The local placement for any IfcBuildingElementProxy is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations. The local placement can be given relatively.

- The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.
- If the relative placement is not used, the absolute placement is defined within the world coordinate system.

Geometric Representation

Currently, the use of the representation types 'BoundingBox', 'GeometricSet', 'GeometricCurveSet', 'SweptSolid', 'SurfaceModel', 'Brep', and 'MappedRepresentation' are allowed. The geometry use definitions for 'BoundingBox', 'SurfaceModel', 'Brep', and 'MappedRepresentation' are explained at the supertype IfcBuildingElement.

GeometricCurveSet Representation

Any building element proxy may be represented by a geometric curve set, given by a collection of 2D points and curves. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

- RepresentationIdentifier: 'FootPrint'
- RepresentationType: 'GeometricCurveSet'

GeometricSet Representation

Any building element proxy may be represented by a geometric set, given by a collection of 2D and 3D points, curves, and surfaces. It represents the body of the proxy object, when no topological structure is available. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

- RepresentationIdentifier: 'Body'
- RepresentationType: 'GeometricSet'

Swept Solid Representation

Any building element proxy may be represented by swept solid geometry (either by extrusion or by revolution). The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

- RepresentationIdentifier: 'Body'
- RepresentationType: 'SweptSolid'

No further restrictions (e.g., for the profile or extrusion direction) are defined at this level. A single or multiple swept area solid(s) can be the Items of the IfcShapeRepresentation.

EXPRESS specification:

ENTITY IfcBuildingElementProxy
SUBTYPE OF ( | IfcBuildingElement);
CompositionType | : | OPTIONAL IfcElementCompositionEnum;
WHERE
WR1 | : | EXISTS(SELF\IfcRoot.Name);
END_ENTITY;

Attribute definitions:

CompositionType | : | Indication, whether the proxy is intended to form an aggregation (COMPLEX), an integral element (ELEMENT), or a part in an aggregation (PARTIAL).

Formal Propositions:

WR1 | : | A Name attribute should be asserted for a building element proxy.

Inheritance graph

ENTITY IfcBuildingElementProxy;
ENTITY IfcRoot;
GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;
ENTITY IfcObjectDefinition;
INVERSE
HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
IsDecomposedBy | : | SET OF IfcRelDecomposes FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelDecomposes FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject;
ObjectType | : | OPTIONAL IfcLabel;
INVERSE
IsDefinedBy | : | SET OF IfcRelDefines FOR RelatedObjects;
ENTITY IfcProduct;
ObjectPlacement | : | OPTIONAL IfcObjectPlacement;
Representation | : | OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy | : | SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcElement;
Tag | : | OPTIONAL IfcIdentifier;
INVERSE
HasStructuralMember | : | SET OF IfcRelConnectsStructuralElement FOR RelatingElement;
FillsVoids | : | SET [0:1] OF IfcRelFillsElement FOR RelatedBuildingElement;
ConnectedTo | : | SET OF IfcRelConnectsElements FOR RelatingElement;
HasCoverings | : | SET OF IfcRelCoversBldgElements FOR RelatingBuildingElement;
HasProjections | : | SET OF IfcRelProjectsElement FOR RelatingElement;
ReferencedInStructures | : | SET OF IfcRelReferencedInSpatialStructure FOR RelatedElements;
HasPorts | : | SET OF IfcRelConnectsPortToElement FOR RelatedElement;
HasOpenings | : | SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
IsConnectionRealization | : | SET OF IfcRelConnectsWithRealizingElements FOR RealizingElements;
ProvidesBoundaries | : | SET OF IfcRelSpaceBoundary FOR RelatedBuildingElement;
ConnectedFrom | : | SET OF IfcRelConnectsElements FOR RelatedElement;
ContainedInStructure | : | SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
ENTITY IfcBuildingElement;
ENTITY IfcBuildingElementProxy;
CompositionType | : | OPTIONAL IfcElementCompositionEnum;
END_ENTITY;