IfcBuilding

Natural language names
Gebäude
Building
Bâtiment
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcBuilding
      OwnerHistoryMODIFIEDInstantiation changed to OPTIONAL.
      CompositionTypeMODIFIEDInstantiation changed to OPTIONAL.
IFC4x2 DRAFT 1
    IfcBuilding
      PositionedRelativeToADDED
Semantic definitions at the entity
Entity definition

A building represents a structure that provides shelter for its occupants or contents and stands in one place. The building is also used to provide a basic element within the spatial structure hierarchy for the components of a building project (together with site, storey, and space).

NOTE  Definition from ISO 6707-1:
Construction work that has the provision of shelter for its occupants or contents as one of its main purpose and is normally designed to stand permanently in one place.

A building is (if specified) associated to a site. A building may span over several connected or disconnected buildings. Therefore building complex provides for a collection of buildings included in a site. A building can also be decomposed in (vertical) parts, where each part defines a building section. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow:

The IfcBuilding is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. Figure 150 shows the IfcBuilding as part of the spatial structure. It also serves as the spatial container for building and other elements.

NOTE  Detailed requirements on mandatory element containment and placement structure relationships are given in view definitions and implementer agreements.
IfcBuildingStorey as part of a spatial structure

Figure 150 — Building composition

Systems, such as building service or electrical distribution systems, zonal systems, or structural analysis systems, relate to IfcBuilding by using the objectified relationship IfcRelServicesBuildings.

Figure 151 describes the heights and elevations of the IfcBuilding. It is used to provide the height above sea level of the project height datum for this building, that is, the internal height 0.00. The height 0.00 is often used as a building internal reference height and equal to the floor finish level of the ground floor.

building heights 

Figure 151 — Building elevations

HISTORY  New entity in IFC1.0.
Attribute definitions
#AttributeTypeCardinalityDescription G
10ElevationOfRefHeightIfcLengthMeasure? Elevation above sea level of the reference height used for all storey elevation measures, equals to height 0.0. It is usually the ground floor level.X
11ElevationOfTerrainIfcLengthMeasure? Elevation above the minimal terrain level around the foot print of the building, given in elevation above sea level.X
12BuildingAddressIfcPostalAddress? Address given to the building for postal purposes.X
Inherited definitions from supertypes
Entity inheritance IfcFacility IfcSpatialStructureElement IfcSpatialElement IfcProduct IfcObject IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
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.
X
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.
X
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
IsDeclaredByIfcRelDefinesByObject
@RelatedObjects
S[0:1]Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
X
DeclaresIfcRelDefinesByObject
@RelatingObject
S[0:?]Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
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
ReferencedByIfcRelAssignsToProduct
@RelatingProduct
S[0:?]Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product.X
PositionedRelativeToIfcRelPositions
@RelatedProducts
S[0:1]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
ReferencesElementsIfcRelReferencedInSpatialStructure
@RelatingStructure
S[0:?]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.
IFC2x3 CHANGE  The inverse attribute has been added with upward compatibility for file based exchange.
Ø\X
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
IfcFacility
IfcBuilding
10ElevationOfRefHeightIfcLengthMeasure? Elevation above sea level of the reference height used for all storey elevation measures, equals to height 0.0. It is usually the ground floor level.X
11ElevationOfTerrainIfcLengthMeasure? Elevation above the minimal terrain level around the foot print of the building, given in elevation above sea level.X
12BuildingAddressIfcPostalAddress? Address given to the building for postal purposes.X
Definitions applying to General Usage

 Instance diagram


Concept usage

Spatial Composition

The Spatial Composition concept template applies to this entity as shown in Table 31.

RelatingObjectDescription
Direct assignment to project, if the building is the outermost spatial container, and no site information is provided for building projects

Table 31 — IfcBuilding Spatial Composition

NOTE  By using the inverse relationship IfcBuilding.Decomposes it references IfcProject || IfcSite || IfcBuilding through IfcRelAggregates.RelatingObject. If it refers to another instance of IfcBuilding, the referenced IfcBuilding needs to have a different and higher CompositionType, i.e. COMPLEX (if the other IfcBuilding has ELEMENT), or ELEMENT (if the other IfcBuilding has PARTIAL).


Spatial Decomposition

The Spatial Decomposition concept template applies to this entity as shown in Table 32.

RelatedObjectsDescription
Spatial decomposition into building stories.

Table 32 — IfcBuilding Spatial Decomposition

NOTE  By using the inverse relationship IfcBuilding.IsDecomposedBy it references IfcBuilding || IfcBuildingStorey through IfcRelAggregates.RelatedObjects. If it refers to another instance of IfcBuilding, the referenced IfcBuilding needs to have a different and lower CompositionType, i.e. ELEMENT (if the other IfcBuilding has COMPLEX), or PARTIAL (if the other IfcBuilding has ELEMENT).


Spatial Container

The Spatial Container concept template applies to this entity as shown in Table 33.

TypeDescription
Physical elements contained in the building.

Table 33 — IfcBuilding Spatial Container

NOTE  If there are building elements and/or other elements directly related to the IfcBuilding (like a curtain wall spanning several stories), they are associated with the IfcBuilding by using the objectified relationship IfcRelContainedInSpatialStructure. The IfcBuilding references them by its inverse relationship:
  • IfcBuilding.ContainsElements -- referencing any subtype of IfcProduct (with the exception of other spatial structure element) by IfcRelContainedInSpatialStructure.RelatedElements.


Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 34.

PsetNameProperties
Pset_BuildingCommon
TemplatePropertyNameValue
Single ValueReferenceIfcIdentifier
Single ValueBuildingIDIfcIdentifier
Single ValueIsPermanentIDIfcBoolean
Single ValueConstructionMethodIfcLabel
Single ValueFireProtectionClassIfcLabel
Single ValueSprinklerProtectionIfcBoolean
Single ValueSprinklerProtectionAutomaticIfcBoolean
Single ValueOccupancyTypeIfcLabel
Single ValueGrossPlannedAreaIfcAreaMeasure
Single ValueNetPlannedAreaIfcAreaMeasure
Single ValueNumberOfStoreysIfcInteger
Single ValueYearOfConstructionIfcLabel
Single ValueYearOfLastRefurbishmentIfcLabel
Single ValueIsLandmarkedIfcLogical
Pset_BuildingUse
TemplatePropertyNameValueUpperValueLowerValueSetValue
Single ValueMarketCategoryIfcLabel
Single ValueMarketSubCategoryIfcLabel
Single ValuePlanningControlStatusIfcLabel
Single ValueNarrativeTextIfcText
Single ValueVacancyRateInCategoryNowIfcPositiveRatioMeasure
Single ValueVacancyRateInCategoryFutureIfcPositiveRatioMeasure
Bounded ValueRentalRatesInCategoryNowIfcMonetaryMeasure
Bounded ValueRentalRatesInCategoryFutureIfcMonetaryMeasure
Pset_BuildingUseAdjacent
TemplatePropertyNameValue
Single ValueMarketCategoryIfcLabel
Single ValueMarketSubCategoryIfcLabel
Single ValuePlanningControlStatusIfcLabel
Single ValueNarrativeTextIfcText
Pset_OutsideDesignCriteria
TemplatePropertyNameValueReference
Single ValueHeatingDryBulbIfcThermodynamicTemperatureMeasure
Single ValueHeatingWetBulbIfcThermodynamicTemperatureMeasure
Single ValueHeatingDesignDayIfcDateTime
Single ValueCoolingDryBulbIfcThermodynamicTemperatureMeasure
Single ValueCoolingWetBulbIfcThermodynamicTemperatureMeasure
Single ValueCoolingDesignDayIfcDateTime
Single ValueWeatherDataStationIfcText
Single ValueWeatherDataDateIfcDateTime
Single ValuePrevailingWindDirectionIfcPlaneAngleMeasure
Single ValuePrevailingWindVelocityIfcLinearVelocityMeasure
Enumerated ValueBuildingThermalExposureIfcLabel

Table 34 — IfcBuilding Property Sets for Objects



Quantity Sets

The Quantity Sets concept template applies to this entity as shown in Table 35.

QsetNameQuantities
Qto_BuildingBaseQuantities

Table 35 — IfcBuilding Quantity Sets



Placement

The Product Local Placement concept applies to this entity.

The local placement for IfcBuilding 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.



FootPrint GeomSet Geometry

The FootPrint GeomSet Geometry concept template applies to this entity as shown in Table 36.

Table 36 — IfcBuilding FootPrint GeomSet Geometry

The foot print representation of IfcBuilding is given by either a single 2D curve (such as IfcPolyline or IfcCompositeCurve), or by a list of 2D curves (in case of inner boundaries), if the building has an independent geometric representation.

NOTE  The independent geometric representation of IfcBuilding may not be allowed in certain model view definitions. In those cases only the contained elements and spaces have an independent geometric representation.


Body Geometry

The Body Geometry concept applies to this entity.

The body (or solid model) geometric representation (if the building has an independent geometric representation) of IfcBuilding is defined using faceted B-Rep capabilities (with or without voids), based on the IfcFacetedBrep or on the IfcFacetedBrepWithVoids.

NOTE  Since the building shape is usually described by the exterior building elements, an independent shape representation shall only be given, if the building is exposed independently from its constituting elements and such independent geometric representation may be prohibited in model view definitions.


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="d3ddf79c-d958-4917-b9d1-da8415c2cb50" name="IfcBuilding" status="sample" applicableRootEntity="IfcBuilding">
  <Applicability uuid="00000000-0000-0000-0000-000000000000" status="sample">
    <Template ref="93b2e847-5329-4c78-9f2f-49995219a393" />
    <TemplateRules operator="and" />
  </Applicability>
  <Concepts>
    <Concept uuid="8740d919-7bb6-45f5-9150-329cbc0a2e5d" name="Spatial Composition" status="sample" override="false">
      <Template ref="8c0fd2f7-71bb-4e6e-8fdb-0c02b352f14a" />
      <TemplateRules operator="and">
        <TemplateRule Description="Direct assignment to project, if the building is the outermost spatial container, and no site information is provided for building projects" Parameters="" />
        <TemplateRule Description="Assignment to site, if the building is the spatial container for the building project with site information " Parameters="" />
        <TemplateRule Description="Assignment to another building as spatial container, e.g. if this building represents a building section." Parameters="" />
      </TemplateRules>
    </Concept>
    <Concept uuid="d4f9e9ca-1b65-40d6-b5bb-d09701fba481" name="Spatial Decomposition" status="sample" override="false">
      <Template ref="667f8443-ecce-4a8d-a63f-931fab0453e0" />
      <TemplateRules operator="and">
        <TemplateRule Description="Spatial decomposition into building stories." Parameters="" />
        <TemplateRule Description="Spatial decomposition into other buildings, e.g. if this building represents a complex building that is subdivided into building sections. " Parameters="" />
      </TemplateRules>
    </Concept>
    <Concept uuid="1b10e0cf-9b2a-4b99-9377-aa6ded511e32" name="Spatial Container" status="sample" override="false">
      <Template ref="61dd08ed-fd01-4955-9337-8afd284a0e6f" />
      <TemplateRules operator="and">
        <TemplateRule Description="Physical elements contained in the building." Parameters="" />
        <TemplateRule Description="Annotations that are directly related to the building." Parameters="" />
        <TemplateRule Description="Grids that are directly related to the building." Parameters="" />
      </TemplateRules>
    </Concept>
    <Concept uuid="018e9e73-39f6-432a-8eb3-80fa71c23a62" name="Property Sets for Objects" status="sample" override="false">
      <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="PsetName[Value]='Pset_BuildingCommon'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_BuildingUse'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_BuildingUseAdjacent'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_OutsideDesignCriteria'" />
      </TemplateRules>
    </Concept>
    <Concept uuid="48f4e672-4912-414f-a96c-e7b5b7e5f2bf" name="Quantity Sets" status="sample" override="false">
      <Template ref="6652398e-6579-4460-8cb4-26295acfacc7" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="QsetName[Value]='Qto_BuildingBaseQuantities'" />
      </TemplateRules>
    </Concept>
    <Concept uuid="542fa98a-c19b-469c-9f73-8f487416ac58" name="Placement" status="sample" override="false">
      <Template ref="cbe85b5f-7912-4a43-8bb7-1e63bf40b26d" />
    </Concept>
    <Concept uuid="7c219577-fe60-4218-bc2e-790c653387f9" name="FootPrint GeomSet Geometry" status="sample" override="false">
      <Template ref="9456d6d6-a62a-48b4-baff-be2e38baac9c" />
    </Concept>
    <Concept uuid="6230b7f3-9991-45e1-9781-bad642b8bce1" name="Body Geometry" status="sample" override="false">
      <Template ref="c446bd16-2de3-4b97-b34f-4446ac0badc2" />
    </Concept>
  </Concepts>
</ConceptRoot>
Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
IfcObjectDefinition
Classification AssociationClassification AssociationGeneral Usage
IfcObject
Object User IdentityObject User IdentityGeneral Usage
Object Predefined TypeObject Predefined TypeGeneral Usage
Object TypingObject TypingGeneral Usage
Property Sets with OverrideProperty Sets with OverrideGeneral Usage
IfcProduct
Product PlacementProduct PlacementGeneral Usage
Product Geometric RepresentationProduct Geometric RepresentationGeneral Usage
IfcBuilding
Spatial CompositionSpatial CompositionGeneral Usage
Spatial DecompositionSpatial DecompositionGeneral Usage
Spatial ContainerSpatial ContainerGeneral Usage
Property Sets for ObjectsProperty Sets for ObjectsGeneral Usage
Quantity SetsQuantity SetsGeneral Usage
PlacementProduct Local PlacementGeneral Usage
FootPrint GeomSet GeometryFootPrint GeomSet GeometryGeneral Usage
Body GeometryBody GeometryGeneral Usage
Formal representations
XML Specification
 <xs:element name="IfcBuilding" type="ifc:IfcBuilding" substitutionGroup="ifc:IfcFacility" nillable="true"/>
 <xs:complexType name="IfcBuilding">
  <xs:complexContent>
   <xs:extension base="ifc:IfcFacility">
    <xs:sequence>
     <xs:element name="BuildingAddress" type="ifc:IfcPostalAddress" nillable="true" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="ElevationOfRefHeight" type="ifc:IfcLengthMeasure" use="optional"/>
    <xs:attribute name="ElevationOfTerrain" type="ifc:IfcLengthMeasure" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcBuilding
 SUBTYPE OF (IfcFacility);
  ElevationOfRefHeight : OPTIONAL IfcLengthMeasure;
  ElevationOfTerrain : OPTIONAL IfcLengthMeasure;
  BuildingAddress : OPTIONAL IfcPostalAddress;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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