IfcSlab

Natural language names
deDecke / Dachfläche / Bodenplatte
enSlab
frDalle
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcSlab
      OwnerHistoryMODIFIEDInstantiation changed to OPTIONAL.
Semantic definitions at the entity
Entity definition

A slab is a component of the construction that normally encloses a space vertically. The slab may provide the lower support (floor) or upper construction (roof slab) in any space in a building.

NOTE  Definition according to ISO 6707-1
thick, flat or shaped component, usually larger than 300 mm square, used to form a covering or projecting from a building.

Only the core or constructional part of this construction is considered to be a slab. The upper finish (flooring, roofing) and the lower finish (ceiling, suspended ceiling) are considered to be coverings. A special type of slab is the landing, described as a floor section to which one or more stair flights or ramp flights connect.

NOTE  There is a representation of slabs for structural analysis provided by a proper subtype of IfcStructuralMember being part of the IfcStructuralAnalysisModel.
NOTE  An arbitrary planar element to which this semantic information is not applicable or irrelevant shall be modeled as IfcPlate.

A slab may have openings, such as floor openings, or recesses. They are defined by an IfcOpeningElement attached to the slab using the inverse relationship HasOpenings pointing to IfcRelVoidsElement.

There are three entities for slab occurrences:

HISTORY  New entity in IFC2.0; it is a merger of the two previous entities IfcFloor, IfcRoofSlab, introduced in IFC1.0
Attribute definitions
#AttributeTypeCardinalityDescription G
9PredefinedTypeIfcSlabTypeEnum? Predefined generic type for a slab that is specified in an enumeration. There may be a property set given specifically for the predefined types.
NOTE  The PredefinedType shall only be used, if no IfcSlabType is assigned, providing its own IfcSlabType.PredefinedType.
IFC2x CHANGE The attribute has been changed into an OPTIONAL attribute.
X
Formal Propositions
RuleDescription
CorrectPredefinedTypeEither the PredefinedType attribute is unset (e.g. because an IfcSlabType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
CorrectTypeAssignedEither there is no slab type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcSlabType.
Inherited definitions from supertypes
Entity inheritance IfcSlabElementedCase IfcSlabStandardCase IfcBuildingElement IfcElement 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
IfcElement
8TagIfcIdentifier? The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level.X
FillsVoidsIfcRelFillsElement
@RelatedBuildingElement
S[0:1]Reference to the IfcRelFillsElement Relationship that puts the element as a filling into the opening created within another element. X
ConnectedToIfcRelConnectsElements
@RelatingElement
S[0:?]Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to. X
IsInterferedByElementsIfcRelInterferesElements
@RelatedElement
S[0:?]Reference to the interference relationship to indicate the element that is interfered. The relationship, if provided, indicates that this element has an interference with one or many other elements.
NOTE  There is no indication of precedence between IsInterferedByElements and InterferesElements.
IFC4 CHANGE New inverse relationship.
X
InterferesElementsIfcRelInterferesElements
@RelatingElement
S[0:?]Reference to the interference relationship to indicate the element that interferes. The relationship, if provided, indicates that this element has an interference with one or many other elements.
NOTE  There is no indication of precedence between IsInterferedByElements and InterferesElements.
IFC4 CHANGE New inverse relationship.
X
HasProjectionsIfcRelProjectsElement
@RelatingElement
S[0:?]Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement.X
ReferencedInStructuresIfcRelReferencedInSpatialStructure
@RelatedElements
S[0:?]Reference relationship to the spatial structure element, to which the element is additionally associated. This relationship may not be hierarchical, an element may be referenced by zero, one or many spatial structure elements.
IFC2x3 CHANGE  The inverse attribute has been added with upward compatibility for file based exchange.
X
HasOpeningsIfcRelVoidsElement
@RelatingBuildingElement
S[0:?]Reference to the IfcRelVoidsElement relationship that creates an opening in an element. An element can incorporate zero-to-many openings. For each opening, that voids the element, a new relationship IfcRelVoidsElement is generated. X
IsConnectionRealizationIfcRelConnectsWithRealizingElements
@RealizingElements
S[0:?]Reference to the connection relationship with realizing element. The relationship, if provided, assigns this element as the realizing element to the connection, which provides the physical manifestation of the connection relationship. X
ProvidesBoundariesIfcRelSpaceBoundary
@RelatedBuildingElement
S[0:?]Reference to space boundaries by virtue of the objectified relationship IfcRelSpaceBoundary. It defines the concept of an element bounding spaces. X
ConnectedFromIfcRelConnectsElements
@RelatedElement
S[0:?]Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element. X
ContainedInStructureIfcRelContainedInSpatialStructure
@RelatedElements
S[0:1]Containment relationship to the spatial structure element, to which the element is primarily associated. This containment relationship has to be hierachical, i.e. an element may only be assigned directly to zero or one spatial structure. X
HasCoveringsIfcRelCoversBldgElements
@RelatingBuildingElement
S[0:?]Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversBldgElement. It defines the concept of an element having coverings associated.X
IfcBuildingElement
IfcSlab
9PredefinedTypeIfcSlabTypeEnum? Predefined generic type for a slab that is specified in an enumeration. There may be a property set given specifically for the predefined types.
NOTE  The PredefinedType shall only be used, if no IfcSlabType is assigned, providing its own IfcSlabType.PredefinedType.
IFC2x CHANGE The attribute has been changed into an OPTIONAL attribute.
X
Definitions applying to General Usage

 Instance diagram


Concept usage

Object Typing

The Object Typing concept template applies to this entity as shown in Table 162.

HasTypeRelatingTypeTypeName
IfcSlabType 

Table 162 — IfcSlab Object Typing



Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 163.

PredefinedTypePsetNameProperties
 Pset_SlabCommon
 Pset_ConcreteElementGeneral
 Pset_PrecastConcreteElementFabrication
 Pset_PrecastConcreteElementGeneral
 Pset_PrecastSlab
 Pset_ReinforcementBarPitchOfSlab
 Pset_EnvironmentalImpactIndicators
 Pset_EnvironmentalImpactValues
 Pset_Condition
 Pset_ManufacturerOccurrence
 Pset_ManufacturerTypeInformation
 Pset_ServiceLife
 Pset_Warranty

Table 163 — IfcSlab Property Sets for Objects



Quantity Sets

The Quantity Sets concept template applies to this entity as shown in Table 164.

QsetNameQuantities
Qto_SlabBaseQuantities

Table 164 — IfcSlab Quantity Sets



Material Layer Set

The Material Layer Set concept applies to this entity.

The material of the IfcSlab is defined by IfcMaterialLayerSet, or as fallback by IfcMaterial, and it is attached either directly or at the IfcSlabType.

NOTE  It is illegal to assign an IfcMaterialLayerSetUsage to an IfcSlab. Only the subtype IfcSlabStandardCase supports this concept.


Spatial Containment

The Spatial Containment concept template applies to this entity as shown in Table 165.

RelatingStructureDescription
IfcBuildingStoreyDefault spatial container
IfcBuildingSpatial container for the element if it cannot be assigned to a building storey
IfcSiteSpatial container for the element in case that it is placed on site (outside of building)

Table 165 — IfcSlab Spatial Containment

The IfcSlab, as any subtype of IfcBuildingElement, may participate alternatively in one of the two different containment relationships:

  • the Spatial Containment (defined here), or
  • the Element Composition.


Surface Geometry

The Surface Geometry concept applies to this entity.

NOTE  The 'Surface' can be used to define a surfacic model of the building (e.g. for analytical purposes, or for reduced Level of Detail representation).


Body SweptSolid Geometry

The Body SweptSolid Geometry concept applies to this entity.

The following additional constraints apply to the swept solid representation:

  • Solid: IfcExtrudedAreaSolid is required,
  • Profile: IfcArbitraryClosedProfileDef, IfcRectangleProfileDef, IfcCircleProfileDef, IfcEllipseProfileDef shall be supported.
  • Extrusion: The profile can be extruded perpendicularly or non-perpendicularly to the plane of the swept profile.

Figure 238 illustrates a 'SweptSolid' geometric representation.

NOTE  The following interpretation of dimension parameter applies for polygonal slabs (in ground floor view):
  • IfcArbitraryClosedProfileDef.OuterCurve: closed bounded curve interpreted as area (or foot print) of the slab.
standard slab

Figure 238 — Slab body extrusion



Body Clipping Geometry

The Body Clipping Geometry concept applies to this entity.

The following constraints apply to the 'Clipping' representation:

  • Solid: see 'SweptSolid' shape representation,
  • Profile: see 'SweptSolid' shape representation,
  • Extrusion: see 'SweptSolid' shape representation,
  • Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid.

Figure 239 illustrates a 'Clipping' geometric representation with definition of a roof slab using advanced geometric representation. The profile is extruded non-perpendicular and the slab body is clipped at the eave.

advanced slab

Figure 239 — Slab body clipping



Voiding

The Element Voiding concept template applies to this entity as shown in Table 166.

HasOpeningsHasFillingsRelatedFillingsDescription
Indicates a partial recess or full opening that may or may not be filled by another element.

Table 166 — IfcSlab Element Voiding



Product Assignment

The Product Assignment concept template applies to this entity as shown in Table 167.

TypeDescription
IfcStructuralSurfaceMemberAn idealized structural member corresponding to the slab.
IfcTaskA task for operating on the slab.

Table 167 — IfcSlab Product Assignment



mvdXML Specification
<?xml version="1.0"?>
<ConceptRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="5ae6aa9b-4593-41d7-9655-423f2a51d4e4" name="IfcSlab" status="sample" applicableRootEntity="IfcSlab">
  <Concepts>
    <Concept uuid="c735df4f-e31d-4960-9463-8dc1eeb291b4" name="Object Typing" status="sample" override="false">
      <Template ref="35a2e10e-20df-40f4-ab2f-dacf0a6744f4" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="RelatingType[Type]='IfcSlabType'" />
      </TemplateRules>
    </Concept>
    <Concept uuid="c832ca52-ff5e-472f-a506-007bed00ef46" name="Property Sets for Objects" status="sample" override="false">
      <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="PsetName[Value]='Pset_SlabCommon'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_ConcreteElementGeneral'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_PrecastConcreteElementFabrication'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_PrecastConcreteElementGeneral'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_PrecastSlab'" />
        <TemplateRule Parameters="PsetName[Value]='Pset_ReinforcementBarPitchOfSlab'" />
      </TemplateRules>
    </Concept>
    <Concept uuid="e5df49c5-071d-46fc-8a89-2b08744235ef" name="Quantity Sets" status="sample" override="false">
      <Template ref="6652398e-6579-4460-8cb4-26295acfacc7" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="QsetName[Value]='Qto_SlabBaseQuantities'" />
      </TemplateRules>
    </Concept>
    <Concept uuid="c3149743-3aa6-468f-9534-e2d508129c83" name="Material Layer Set" status="sample" override="false">
      <Template ref="dfb5b3a9-50e3-46e2-8518-1f03e7cfd886" />
    </Concept>
    <Concept uuid="450ddcc2-674b-4851-8339-204d36d209ce" name="Spatial Containment" status="sample" override="false">
      <Template ref="d9a3f822-0014-4bc2-8d94-9d9067759045" />
      <TemplateRules operator="and">
        <TemplateRule Description="Default spatial container" Parameters="RelatingStructure[Type]='IfcBuildingStorey'" />
        <TemplateRule Description="Spatial container for the element if it cannot be assigned to a building storey" Parameters="RelatingStructure[Type]='IfcBuilding'" />
        <TemplateRule Description="Spatial container for the element in case that it is placed on site (outside of building)" Parameters="RelatingStructure[Type]='IfcSite'" />
      </TemplateRules>
    </Concept>
    <Concept uuid="9fb59106-f67f-4c36-99b5-62538a173f98" name="Surface Geometry" status="sample" override="false">
      <Template ref="2e99de70-fb73-478f-9bca-4fedfdeb4ea5" />
    </Concept>
    <Concept uuid="0a146d06-df59-4562-b075-cdccd1a7e1f6" name="Body SweptSolid Geometry" status="sample" override="false">
      <Template ref="cb7c18fa-cf83-4db1-be1b-c013ba4ed672" />
    </Concept>
    <Concept uuid="0b434ff6-66be-43f1-9550-fccff87e07eb" name="Body Clipping Geometry" status="sample" override="false">
      <Template ref="2cdbc2f5-9b0c-43ea-9d2a-9d72d0147e00" />
    </Concept>
    <Concept uuid="6a77c59c-4887-4155-9bd4-a81e7e312456" name="Voiding" status="sample" override="false">
      <Template ref="b9005e79-b5c5-4c0b-9d86-046c21ad420d" />
      <TemplateRules operator="and">
        <TemplateRule Description="Indicates a partial recess or full opening that may or may not be filled by another element." Parameters="" />
      </TemplateRules>
    </Concept>
    <Concept uuid="adb33e8c-8ec0-486f-96df-0a736f0b4f9e" name="Product Assignment" status="sample" override="false">
      <Template ref="ec9cfb04-adfe-4868-8168-d78fe995a913" />
      <TemplateRules operator="and">
        <TemplateRule Description="An idealized structural member corresponding to the slab." Parameters="Type[Type]='IfcStructuralSurfaceMember'" />
        <TemplateRule Description="A task for operating on the slab." Parameters="Type[Type]='IfcTask'" />
      </TemplateRules>
    </Concept>
  </Concepts>
</ConceptRoot>
Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
IfcObject
Object Occurrence Predefined TypeObject Predefined TypeGeneral Usage
IfcProduct
Product PlacementProduct PlacementGeneral Usage
Product Geometric RepresentationProduct Geometric RepresentationGeneral Usage
IfcElement
Product Local PlacementProduct Local PlacementGeneral Usage
CoG GeometryCoG GeometryGeneral Usage
Box GeometryBox GeometryGeneral Usage
FootPrint GeometryFootPrint GeometryGeneral Usage
Body SurfaceOrSolidModel GeometryBody SurfaceOrSolidModel GeometryGeneral Usage
Body SurfaceModel GeometryBody SurfaceModel GeometryGeneral Usage
Body Tessellation GeometryBody Tessellation GeometryGeneral Usage
Body Brep GeometryBody Brep GeometryGeneral Usage
Body AdvancedBrep GeometryBody AdvancedBrep GeometryGeneral Usage
Body CSG GeometryBody CSG GeometryGeneral Usage
Mapped GeometryMapped GeometryGeneral Usage
IfcBuildingElement
Surface 3D GeometrySurface 3D GeometryGeneral Usage
IfcSlab
Object TypingObject TypingGeneral Usage
Property Sets for ObjectsProperty Sets for ObjectsGeneral Usage
Quantity SetsQuantity SetsGeneral Usage
Material Layer SetMaterial Layer SetGeneral Usage
Spatial ContainmentSpatial ContainmentGeneral Usage
Surface GeometrySurface GeometryGeneral Usage
Body SweptSolid GeometryBody SweptSolid GeometryGeneral Usage
Body Clipping GeometryBody Clipping GeometryGeneral Usage
VoidingElement VoidingGeneral Usage
Product AssignmentProduct AssignmentGeneral Usage
Examples
Formal representations
XML Specification
 <xs:element name="IfcSlab" type="ifc:IfcSlab" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>
 <xs:complexType name="IfcSlab">
  <xs:complexContent>
   <xs:extension base="ifc:IfcBuildingElement">
    <xs:attribute name="PredefinedType" type="ifc:IfcSlabTypeEnum" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcSlab
 SUPERTYPE OF(ONEOF(IfcSlabElementedCase, IfcSlabStandardCase))
 SUBTYPE OF (IfcBuildingElement);
  PredefinedType : OPTIONAL IfcSlabTypeEnum;
 WHERE
  CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcSlabTypeEnum.USERDEFINED) OR
((PredefinedType = IfcSlabTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
  CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR
('IFCSHAREDBLDGELEMENTS.IfcSlabType' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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