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IfcSpatialStructureElement

Definition from buildingSMART: 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 proposition:

  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 IFC Release 2x.

Spatial Structure Use Definition

fig1

The figure 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.

EXPRESS specification:

ENTITY IfcSpatialStructureElement
ABSTRACT SUPERTYPE OF (ONEOF(IfcBuilding, IfcBuildingStorey, IfcSpace, IfcSite))
SUBTYPE OF ( IfcProduct);
LongName  :  OPTIONAL IfcLabel;
CompositionType  :  IfcElementCompositionEnum;
INVERSE
ReferencesElements  :  SET OF IfcRelReferencedInSpatialStructure FOR RelatingStructure;
ServicedBySystems  :  SET OF IfcRelServicesBuildings FOR RelatedBuildings;
ContainsElements  :  SET OF IfcRelContainedInSpatialStructure FOR RelatingStructure;
WHERE
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)) );
END_ENTITY;

Attribute definitions:

LongName  :  Long name for a spatial structure element, used for informal purposes. Maybe used in conjunction with the inherited Name attribute.
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.
ReferencesElements  :  Set of spatial reference relationships, that holds those elements, which are referenced, but not contained, within this element of the project spatial structure.
NOTE  The spatial reference relationship, established by IfcRelReferencedInSpatialStructure, is not required to be an hierarchical relationship, i.e. each element can be assigned to 0, 1 or many spatial structure elements.
EXAMPLE  A curtain wall maybe contained in the ground floor, but maybe referenced in all floors, it reaches.

IFC2x Edition 3 CHANGE  The inverse attribute has been added with upward compatibility for file based exchange.
ServicedBySystems  :  Set of relationships to Systems, that provides a certain service to the Building. The relationship is handled by the objectified relationship IfcRelServicesBuildings.
ContainsElements  :  Set of spatial containment relationships, that holds those elements, which are contained within this element of the project spatial structure.
NOTE  The spatial containment relationship, established by IfcRelContainedInSpatialStructure, is required to be an hierarchical relationship, i.e. each element can only be assigned to 0 or 1 spatial structure element.

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;
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 IfcSpatialStructureElement;
LongName  :  OPTIONAL IfcLabel;
CompositionType  :  IfcElementCompositionEnum;
INVERSE
ReferencesElements  :  SET OF IfcRelReferencedInSpatialStructure FOR RelatingStructure;
ServicedBySystems  :  SET OF IfcRelServicesBuildings FOR RelatedBuildings;
ContainsElements  :  SET OF IfcRelContainedInSpatialStructure FOR RelatingStructure;
END_ENTITY;