IfcSpatialStructureElement

Natural language names
Räumliches Strukturelement
Spatial Structure Element
Elément de la structure spatiale
Semantic definitions at the entity
Entity definition

A spatial structure element 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.

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 127 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.

fig1

Figure 127 — Spatial structure element composition

HISTORY  New entity in IFC2x.

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.
Attribute definitions
#AttributeTypeCardinalityDescription R
9CompositionTypeIfcElementCompositionEnum? 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.
X
Formal Propositions
RuleDescription
WR41All spatial structure elements shall be associated (using the IfcRelAggregates relationship) with another spatial structure element, or with IfcProject.
Inherited definitions from supertypes
Entity inheritance IfcBuilding IfcBuildingStorey IfcSite IfcSpace IfcSpatialElement IfcProduct IfcObject IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionR
IfcRoot
1GlobalIdIfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory? Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object,
NOTE  only the last modification in stored - either as addition, deletion or modification.
IFC4 CHANGE  The attribute has been changed to be OPTIONAL.
X
3NameIfcLabel? Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule. X
4DescriptionIfcText? Optional description, provided for exchanging informative comments.X
IfcObjectDefinition
HasAssignmentsIfcRelAssigns
@RelatedObjects		S[0:?]Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.X
NestsIfcRelNests
@RelatedObjects		S[0:1]References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE  The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.
IsNestedByIfcRelNests
@RelatingObject		S[0:?]References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).
IFC4 CHANGE  The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.
X
HasContextIfcRelDeclares
@RelatedDefinitions		S[0:1]References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.
IFC4 CHANGE  The inverse attribute datatype has been added.
IsDecomposedByIfcRelAggregates
@RelatingObject		S[0:?]References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).
IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
X
DecomposesIfcRelAggregates
@RelatedObjects		S[0:1]References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
X
HasAssociationsIfcRelAssociates
@RelatedObjects		S[0:?]Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.X
IfcObject
5ObjectTypeIfcLabel? The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED.
X
IsTypedByIfcRelDefinesByType
@RelatedObjects		S[0:1]Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.
IFC4 CHANGE  New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange.
X
IsDefinedByIfcRelDefinesByProperties
@RelatedObjects		S[0:?]Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.
IFC4 CHANGE  The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange.
X
IfcProduct
6ObjectPlacementIfcObjectPlacement? Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system.X
7RepresentationIfcProductRepresentation? Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement.X
IfcSpatialElement
8LongNameIfcLabel? Long name for a spatial structure element, used for informal purposes. It should be used, if available, in conjunction with the inherited Name attribute.
NOTE  In many scenarios the Name attribute refers to the short name or number of a spacial element, and the LongName refers to the full descriptive name.
X
ContainsElementsIfcRelContainedInSpatialStructure
@RelatingStructure		S[0:?]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, where each element can only be assigned to 0 or 1 spatial structure element.
X
ServicedBySystemsIfcRelServicesBuildings
@RelatedBuildings		S[0:?]Set of relationships to systems, that provides a certain service to the spatial element for which it is defined. The relationship is handled by the objectified relationship IfcRelServicesBuildings.
IFC4 CHANGE  The inverse attribute has been promoted to the new supertype IfcSpatialElement with upward compatibility for file based exchange.
X
IfcSpatialStructureElement
9CompositionTypeIfcElementCompositionEnum? 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.
X
Definitions applying to Reference View

 Instance diagram

Concept usage

Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 42.

PsetNameProperties
Pset_PropertyAgreement
TemplatePropertyNameValueReference
Enumerated ValueAgreementTypeIfcLabelPEnum_PropertyAgreementType
Single ValueIdentifierIfcIdentifier
Single ValueVersionIfcLabel
Single ValueVersionDateIfcDate
Single ValuePropertyNameIfcLabel
Single ValueCommencementDateIfcDate
Single ValueTerminationDateIfcDate
Single ValueDurationIfcDuration
Single ValueOptionsIfcText
Single ValueConditionCommencementIfcText
Single ValueRestrictionsIfcText
Single ValueConditionTerminationIfcText

Table 42 — IfcSpatialStructureElement Property Sets for Objects



mvdXML Specification
<?xml version="1.0"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="34e273a5-f732-4021-bbc6-7a11b13d3c26" name="IfcSpatialStructureElement" status="sample" applicableRootEntity="IfcSpatialStructureElement">
  <Applicability uuid="00000000-0000-0000-0000-000000000000" status="sample">
    <Template ref="0d1d4c23-7c95-4d63-8d7a-36408cb3cfea" />
    <TemplateRules operator="and" />
  </Applicability>
  <Concepts>
    <Concept uuid="f8b1bb98-5339-4954-aed3-67c774c9e47e" name="Property Sets for Objects" status="sample" override="false">
      <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="PsetName=Pset_PropertyAgreement;" />
      </TemplateRules>
    </Concept>
  </Concepts>
</ConceptRoot>
Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityReference View
Revision ControlRevision ControlReference View
IfcObjectDefinition
ClassificationClassificationReference View
IfcObject
Object User IdentityObject User IdentityReference View
Object Predefined TypeObject Predefined TypeReference View
Object TypingObject TypingReference View
Property Sets for ObjectsProperty Sets with OverrideReference View
IfcSpatialElement
Spatial Element Type Predefined TypeSpatial Element Type Predefined TypeReference View
IfcSpatialStructureElement
Property Sets for ObjectsProperty Sets for ObjectsReference View
Formal representations
XML Specification
 <xs:element name="IfcSpatialStructureElement" type="ifc:IfcSpatialStructureElement" abstract="true" substitutionGroup="ifc:IfcSpatialElement" nillable="true"/>
 <xs:complexType name="IfcSpatialStructureElement" abstract="true">
  <xs:complexContent>
   <xs:extension base="ifc:IfcSpatialElement">
    <xs:attribute name="CompositionType" type="ifc:IfcElementCompositionEnum" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcSpatialStructureElement
 ABSTRACT SUPERTYPE OF(ONEOF(IfcBuilding, IfcBuildingStorey, IfcSite, IfcSpace))
 SUBTYPE OF (IfcSpatialElement);
  CompositionType : OPTIONAL IfcElementCompositionEnum;
 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;

Link to EXPRESS-G diagram EXPRESS-G diagram

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