#### 5.4.3.2 IfcBuildingElement

| Elément de construction
| Bauteil / Bauelement

The building element comprises all elements that are primarily part of the construction of a building, i.e., its structural and space separating system.

> "Major functional part of a building, examples are foundation, floor, roof, wall." ISO 6707-1

> EXAMPLE Building elements are walls, beams, or doors, they are all physically existent and tangible things.

The IfcBuildingElement utilizes the following capabilities mainly through inverse attributes referencing objectified relationships:

> NOTE View definitions and implementer agreements will determine those relationships that have to be supported in actual exchange.

1. Grouping - being part of a logical group of objects
   - objectified relationship: IfcRelAssignsToGroup
   - object referenced by relationship: IfcGroup (and subtypes)
   - inverse attribute: HasAssignment
2. Work processes - reference to work tasks, in which this building element is used
   - objectified relationship: IfcRelAssignsToProcess
   - object referenced by relationship: IfcProcess (and subtypes)
   - inverse attribute: HasAssignments
3. Structural member reference - information whether the building element is represented in a structural analysis model by a structural member
   - objectified relationship: IfcRelAssignsToProduct
   - object referenced by relationship: IfcStructuralMember (and by default IfcStructuralCurveMember)
   - inverse attribute: HasAssignments
4. Aggregation - aggregated together with other elements to form an aggregate
   - objectified relationship: IfcRelAggregates
   - object referenced by relationship: IfcElement (and subtypes)
   - inverse attribute (for container): IsDecomposedBy
   - inverse attribute (for contained parts): Decomposes
5. Material - assignment of material used by this building element
   - objectified relationship: IfcRelAssociatesMaterial
   - object referenced by relationship: IfcMaterialSelect (and selected items)
   - inverse attribute: HasAssociations
6. Classification - assigned reference to an external classification
   - objectified relationship: IfcRelAssociatesClassification
   - object referenced by relationship: IfcClassificationNotationSelect (and selected items, default IfcClassificationReference)
   - inverse attribute: HasAssociations
7. Library - assigned reference to an external library item reference
   - objectified relationship: IfcRelAssociatesClassification
   - object referenced by relationship: IfcLibrarySelect (and selected items, default IfcLibraryReference)
   - inverse attribute: HasAssociations
8. Documentation - assigned reference to an external documentation
   - objectified relationship: IfcRelAssociatesDocumentation
   - object referenced by relationship: IfcDocumentSelect (and selected items, default IfcDocumentReference)
   - inverse attribute: HasAssociations
9. Type - reference to the common product type information for the element occurrence
   - objectified relationship: IfcRelDefinesByType
   - object referenced by relationship: IfcBuildingElementType (and subtypes)
   - inverse attribute: IsTypedBy
10. Properties - reference to all attached properties, including quantities
    - objectified relationship: IfcRelDefinesByProperties
    - object referenced by relationship: IfcPropertySetDefinition (default IfcPropertySet)
    - inverse attribute: IsDefinedBy
11. Connection - connectivity to other elements, including the definition of the joint
    - objectified relationship: IfcRelConnectsElements
    - object referenced by relationship: IfcElement
    - inverse attribute: ConnectedTo
    - inverse attribute: ConnectedFrom
12. Realization - information, whether the building element is used to realize a connection (e.g. as a weld in a connection between two members)
    - objectified relationship: IfcRelConnectsWithRealizingElements
    - object referenced by relationship: IfcElement
    - inverse attribute: IsConnectionRealization
13. Assignment to spatial structure - hierarchical assignment to the right level within the spatial structure
    - objectified relationship: IfcRelContainedInSpatialStructure
    - object referenced by relationship: IfcSpatialStructureElement
    - inverse attribute: ContainedInStructure
14. Reference to spatial structure(s) - non hierarchical reference to one or more elements within the spatial structure (e.g. a curtain wall, being contained in the building, references several stories)
    - objectified relationship: IfcRelReferencedInSpatialStructure
    - object referenced by relationship: IfcSpatialElement
    - inverse attribute: ReferencedInStructure
15. Boundary - provision of space boundaries by this building element
    - objectified relationship: IfcRelSpaceBoundary
    - object referenced by relationship: IfcSpace
    - inverse attribute: ProvidesBoundaries
16. Coverings - assignment of covering elements to this building element (note: normally covering elements are assigned to the space, only used for special cases)
    - objectified relationship: IfcRelCoversBldgElements
    - object referenced by relationship: IfcCovering
    - inverse attribute: HasCoverings
17. Voids - information, whether the building element includes openings, recesses or other voids
    - objectified relationship: IfcRelVoidsElement
    - object referenced by relationship: IfcFeatureElementSubtraction (default IfcOpeningElement)
    - inverse attribute: HasOpenings
18. Projection - information, whether the building element has projections (such as a fascia)
    - objectified relationship: IfcRelProjectsElement
    - object referenced by relationship: IfcFeatureElementAddition (default IfcProjectionElement)
    - inverse attribute: HasProjections
19. Filling - information whether the building element is used to fill openings
    - objectified relationship: IfcRelFillsElement
    - object referenced by relationship: IfcOpeningElement
    - inverse attribute: FillsVoids

> HISTORY New entity in IFC1.0

XSD Specification:

<xs:element name="IfcBuildingElement" type="ifc:IfcBuildingElement" abstract="true" substitutionGroup="ifc:IfcElement" nillable="true"/>
<xs:complexType name="IfcBuildingElement" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcElement"/>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcBuildingElement

| ABSTRACT SUPERTYPE OF(ONEOF(IfcBeam, IfcCovering, IfcMember, IfcPlate, IfcSlab, IfcWall))

| SUBTYPE OF (IfcElement);

| INVERSE

| WHERE

MaxOneMaterialAssociation | : | SIZEOF (QUERY(temp <* SELF\IfcObjectDefinition.HasAssociations | 'IFCPRODUCTEXTENSION.IFCRELASSOCIATESMATERIAL' IN TYPEOF(temp) )) <= 1;

END_ENTITY;

Attribute Definitions:

Formal Propositions:

MaxOneMaterialAssociation | : | There should be only a maximum of one material association assigned to an building element. NOTE The material association can assign a single material, a set of materials, a set of material layers, or a set of material profiles by a single association relationship. FC2x4 CHANGE The where rule has been promoted from the subtype IfcWall.

Inheritance Graph:

ENTITY IfcBuildingElement

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcObjectDefinition

| INVERSE

HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
Nests | : | SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy | : | SET OF IfcRelNests FOR RelatingObject;
HasContext | : | SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy | : | SET OF IfcRelAggregates FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;

| ENTITY IfcObject

ObjectType | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsDeclaredBy | : | SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares | : | SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy | : | SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy | : | SET OF IfcRelDefinesByProperties FOR RelatedObjects;

| ENTITY IfcProduct

ObjectPlacement | : | OPTIONAL IfcObjectPlacement;
Representation | : | OPTIONAL IfcProductRepresentation;

| INVERSE

ReferencedBy | : | SET OF IfcRelAssignsToProduct FOR RelatingProduct;

| ENTITY IfcElement

Tag | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsInterferedByElements | : | SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements | : | SET OF IfcRelInterferesElements FOR RelatingElement;
ContainedInStructure | : | SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;

| ENTITY IfcBuildingElement

| INVERSE

END_ENTITY;

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