Elément de la structure spatiale
Räumliches Strukturelement

A spatial structure element (IfcSpatialStructureElement) is the generalization of all spatial elements that might be used to define a spatial structure. That spatial structure is often used to provide a project structure to organize a building project.

A spatial project structure might define as many levels of decomposition as necessary for the building project. Elements within the spatial project structure are:

or aggregations or parts thereof. The composition type declares an element to be either an element itself, or an aggregation (complex) or a decomposition (part). The interpretation of these types is given at each subtype of IfcSpatialStructureElement.

The IfcRelAggregates is defined as an 1-to-many relationship and used to establish the relationship between exactly two levels within the spatial project structure. Finally the highest level of the spatial structure is assigned to IfcProject using the IfcRelAggregates.

Informal Propositions:

  1. The spatial project structure, established by the IfcRelAggregates, shall be acyclic.
  2. A site should not be (directly or indirectly) associated to a building, storey or space.
  3. A building should not be (directly or indirectly) associated to a storey or space.
  4. A storey should not be (directly or indirectly) associated to a space.
HISTORY  New entity in IFC2x.

Relationship Use Definition

The subtypes of IfcSpatialStructureElement relate to other elements and systems by establishing the following relationships:

The subtypes of IfcSpatialStructureElement relate to each other by using the IfcRelAggregates relationship to build the project spatial structure.

Figure 153 shows the use of IfcRelAggregates to establish a spatial structure including site, building, building section and storey. More information is provided at the level of the subtypes.


Figure 153 — Spatial structure element composition

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 74.

Table 74 — IfcSpatialStructureElement Property Sets for Objects

XSD Specification:

 <xs:element name="IfcSpatialStructureElement" type="ifc:IfcSpatialStructureElement" abstract="true" substitutionGroup="ifc:IfcSpatialElement" nillable="true"/>
 <xs:complexType name="IfcSpatialStructureElement" abstract="true">
   <xs:extension base="ifc:IfcSpatialElement">
    <xs:attribute name="CompositionType" type="ifc:IfcElementCompositionEnum" use="optional"/>

EXPRESS Specification:

ENTITY IfcSpatialStructureElement
ABSTRACT SUPERTYPE OF(ONEOF(IfcBuilding, IfcBuildingStorey, IfcSite, IfcSpace))
SUBTYPE OF IfcSpatialElement;
CompositionType : OPTIONAL IfcElementCompositionEnum;
WR41 : (HIINDEX(SELF\IfcObjectDefinition.Decomposes) = 1) AND ('IFCKERNEL.IFCRELAGGREGATES' IN TYPEOF(SELF\IfcObjectDefinition.Decomposes[1])) AND (('IFCKERNEL.IFCPROJECT' IN TYPEOF (SELF\IfcObjectDefinition.Decomposes[1].RelatingObject)) OR ('IFCPRODUCTEXTENSION.IFCSPATIALSTRUCTUREELEMENT' IN TYPEOF (SELF\IfcObjectDefinition.Decomposes[1].RelatingObject)) );

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

CompositionType : Denotes, whether the predefined spatial structure element represents itself, or an aggregate (complex) or a part (part). The interpretation is given separately for each subtype of spatial structure element. If no CompositionType is asserted, the dafault value 'ELEMENT' applies.
IFC4 CHANGE  Attribute made optional.

Formal Propositions:

WR41 : All spatial structure elements shall be associated (using the IfcRelAggregates relationship) with another spatial structure element, or with IfcProject.

Inheritance Graph:

ENTITY IfcSpatialStructureElement
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
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 IfcLabel;
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;
ReferencedBy : SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcSpatialElement
LongName : OPTIONAL IfcLabel;
ContainsElements : SET OF IfcRelContainedInSpatialStructure FOR RelatingStructure;
ServicedBySystems : SET OF IfcRelServicesBuildings FOR RelatedBuildings;
ReferencesElements : SET OF IfcRelReferencedInSpatialStructure FOR RelatingStructure;
ENTITY IfcSpatialStructureElement
CompositionType : OPTIONAL IfcElementCompositionEnum;

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