IfcSpace

BACnet MVD

#### IfcSpace

Natural language names

| Raum
| Space
| Local

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcSpace |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.
CompositionType |  |  | MODIFIED | Instantiation changed to OPTIONAL.
PredefinedType |  |  | MODIFIED | Name changed from InteriorOrExteriorSpace to PredefinedType. Type changed from IfcInternalOrExternalEnum to IfcSpaceTypeEnum. Instantiation changed to OPTIONAL.

##### Semantic definitions at the entity

Entity definition

A space represents an area or volume bounded actually or theoretically. Spaces are areas or volumes that provide for certain functions within a building.

A space is associated to a building storey (or in case of exterior spaces to a site). A space may span over several connected spaces. Therefore a space group provides for a collection of spaces included in a storey. A space can also be decomposed in parts, where each part defines a partial space. This is defined by the CompositionType attribute of the supertype IfcSpatialStructureElement which is interpreted as follow:

- COMPLEX = space group
- ELEMENT = space
- PARTIAL = partial space

> NOTE View definitions and implementation agreements may restrict spaces with CompositionType=ELEMENT to be non-overlapping.

The IfcSpace 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 186 shows the IfcSpace as part of the spatial structure. It also serves as the spatial container for space related elements.

> NOTE Detailed requirements on mandatory element containment and placement structure relationships are given in view definitions and implementer agreements.

Figure 186 — Space composition

The following guidelines should apply for using the Name, Description, LongName and ObjectType attributes.

- Name holds the unique name (or space number) from the plan.
- Description holds any additional information field the user may have specified, there are no further recommendations.
- LongName holds the full name of the space, it is often used in addition to the Name, if a number is assigned to the room, then the descriptive name is exchanged as LongName.
- ObjectType holds the space type, i.e. usually the functional category of the space .

> NOTE In cases of inconsistency between the geometric representation of the IfcSpace and the combined geometric representations of the surrounding IfcRelSpaceBoundary, the geometric representation of the space should take priority over the geometric representation of the surrounding space boundaries.

Figure 187 describes the heights and elevations of the IfcSpace.

- elevation of the space (top of construction slab) equals elevation of storey: provided by IfcBuildingStorey.Elevation relative to em>IfcBuilding.ElevationOfRefHeight
- elevation of the space flooring (top of flooring on top of slab): provided by IfcSpace.ElevationWithFlooring relative to IfcBuilding.ElevationOfRefHeight
- height of space (top of slab below to bottom of slab above): provided by BaseQuantity with Name="Height"
- floor height of space (top of slab below to top of flooring): provided by BaseQuantity with Name="FinishFloorHeight"
- net height of space (top of flooring to bottom of suspended ceiling): provided by BaseQuantity with Name="FinishCeilingHeight"

Figure 187 — Space elevations

> HISTORY New entity in IFC1.0

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---

10

PredefinedType

IfcSpaceTypeEnum

?

Predefined generic types for a space that are specified in an enumeration. There might be property sets defined specifically for each predefined type.

> NOTE Previous use had been to indicates whether the IfcSpace is an interior space by value INTERNAL, or an exterior space by value EXTERNAL. This use is now deprecated, the property 'IsExternal' at 'Pset_SpaceCommon' should be used instead.

> IFC4 CHANGE The attribute has been renamed from ExteriorOrInteriorSpace with upward compatibility for file based exchange.

X

11 | ElevationWithFlooring | IfcLengthMeasure | ? | Level of flooring of this space; the average shall be taken, if the space ground surface is sloping or if there are level differences within this space. |  | X

HasCoverings

IfcRelCoversSpaces
@RelatingSpace

S[0:?]

Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversSpaces. It defines the concept of a space having coverings assigned. Those coverings may represent different flooring, or tiling areas.

> NOTE Coverings are often managed by the space, and not by the building element, which they cover.

> IFC2x Edition3 CHANGE New inverse relationship. Upward compatibility for file based exchange is guaranteed.

X

| BoundedBy | IfcRelSpaceBoundary @RelatingSpace | S[0:?] | Reference to a set of IfcRelSpaceBoundary's that defines the physical or virtual delimitation of that space against physical or virtual boundaries. |  | X

Formal Propositions

Rule | Description
--- | ---
CorrectPredefinedType | Either the PredefinedType attribute is unset (e.g. because an IfcSpaceType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
CorrectTypeAssigned | Either there is no space type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcSpaceType.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId |  | Assignment of a globally unique identifier within the entire software world. | X | X

2

OwnerHistory

IfcOwnerHistory

?

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

X

3 | Name | IfcLabel | ? | 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 | X
4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. |  | X
IfcObjectDefinition
| HasAssignments | IfcRelAssigns @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

Nests

IfcRelNests
@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

IsNestedBy

IfcRelNests
@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

X

HasContext

IfcRelDeclares
@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

IsDecomposedBy

IfcRelAggregates
@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

X

Decomposes

IfcRelAggregates
@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

X

| HasAssociations | IfcRelAssociates @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 | X
IfcObject

5

ObjectType

IfcLabel

?

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

IsDeclaredBy

IfcRelDefinesByObject
@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

X

Declares

IfcRelDefinesByObject
@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

IsTypedBy

IfcRelDefinesByType
@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

IsDefinedBy

IfcRelDefinesByProperties
@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
6 | ObjectPlacement | IfcObjectPlacement | ? | 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 | X
7 | Representation | IfcProductRepresentation | ? | 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 | X
| ReferencedBy | IfcRelAssignsToProduct @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
IfcSpatialElement

8

LongName

IfcLabel

?

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

ContainsElements

IfcRelContainedInSpatialStructure
@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

ServicedBySystems

IfcRelServicesBuildings
@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

ReferencesElements

IfcRelReferencedInSpatialStructure
@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

9

CompositionType

IfcElementCompositionEnum

?

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

IfcSpace

10

PredefinedType

IfcSpaceTypeEnum

?

Predefined generic types for a space that are specified in an enumeration. There might be property sets defined specifically for each predefined type.

> NOTE Previous use had been to indicates whether the IfcSpace is an interior space by value INTERNAL, or an exterior space by value EXTERNAL. This use is now deprecated, the property 'IsExternal' at 'Pset_SpaceCommon' should be used instead.

> IFC4 CHANGE The attribute has been renamed from ExteriorOrInteriorSpace with upward compatibility for file based exchange.

X

11 | ElevationWithFlooring | IfcLengthMeasure | ? | Level of flooring of this space; the average shall be taken, if the space ground surface is sloping or if there are level differences within this space. |  | X

HasCoverings

IfcRelCoversSpaces
@RelatingSpace

S[0:?]

Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversSpaces. It defines the concept of a space having coverings assigned. Those coverings may represent different flooring, or tiling areas.

> NOTE Coverings are often managed by the space, and not by the building element, which they cover.

> IFC2x Edition3 CHANGE New inverse relationship. Upward compatibility for file based exchange is guaranteed.

X

| BoundedBy | IfcRelSpaceBoundary @RelatingSpace | S[0:?] | Reference to a set of IfcRelSpaceBoundary's that defines the physical or virtual delimitation of that space against physical or virtual boundaries. |  | X

##### Definitions applying to Design Transfer View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Definitions applying to BACnet View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Formal representations

XML Specification
`<xs:element name="IfcSpace" type="ifc:IfcSpace" substitutionGroup="ifc:IfcSpatialStructureElement" nillable="true"/>
<xs:complexType name="IfcSpace">
<xs:complexContent>
<xs:extension base="ifc:IfcSpatialStructureElement">
<xs:attribute name="PredefinedType" type="ifc:IfcSpaceTypeEnum" use="optional"/>
<xs:attribute name="ElevationWithFlooring" type="ifc:IfcLengthMeasure" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcSpace
SUBTYPE OF (IfcSpatialStructureElement);
PredefinedType : OPTIONAL IfcSpaceTypeEnum;
ElevationWithFlooring : OPTIONAL IfcLengthMeasure;
INVERSE
HasCoverings : SET [0:?] OF IfcRelCoversSpaces FOR RelatingSpace;
BoundedBy : SET [0:?] OF IfcRelSpaceBoundary FOR RelatingSpace;
WHERE
CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcSpaceTypeEnum.USERDEFINED) OR
((PredefinedType = IfcSpaceTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR
('IFCPRODUCTEXTENSION.IfcSpaceType' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

EXPRESS-G diagram

`

References: IfcSpaceBoundarySelect IfcRelCoversSpaces

Link to this page