IfcSlabStandardCase

Natural language names
deDecke / Dachfläche / Bodenplatte - Standard
enSlab Standard Case
frDalle standard
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcSlabStandardCaseADDED
IFC4x1 to IFC4x2
    IfcSlabStandardCase
      PositionedFromADDED
Semantic definitions at the entity
Entity definition

The standard slab, IfcSlabStandardCase, defines a slab with certain constraints for the provision of material usage, parameters and with certain constraints for the geometric representation. The IfcSlabStandardCase handles all cases of slabs, that:

The definitions of slab openings and niches are the same as given at the supertype IfcSlab. The same agreements to the special types of slabs, as defined in the PredefinedType attribute apply as well.

NOTE  If the IfcSlabStandardCase is of type Landing and is used within an IfcStair or IfcRamp, the special agreements to handle stair and ramp geometry will also affect the geometric representation of the IfcSlabStandardCase.
HISTORY  New entity in IFC4.
Formal Propositions
RuleDescription
HasMaterialLayerSetusageA valid instance of IfcSlabStandardCase relies on the provision of an IfcMaterialLayerSetUsage.
Inherited definitions from supertypes
Entity inheritance IfcSlab IfcBuildingElement IfcElement IfcProduct IfcObject IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionB
IfcRoot
1GlobalIdIfcGloballyUniqueId[1:1] Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory[0:1] 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.
X
3NameIfcLabel[0:1] 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[0:1] 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).
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). 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.
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). 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). 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
5ObjectType- This attribute is out of scope for this model view definition and shall not be set.
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. 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. X
IfcProduct
6ObjectPlacementIfcObjectPlacement[0:1] 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[0:1] 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[0:1] 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
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.
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
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.
PositionedFromIfcRelPositions
@RelatingElement
S[0:1]Indicates a constrained placement, where the ObjectPosition must match positioning defined according to the referenced positioning element.X
IfcBuildingElement
IfcSlab
9PredefinedTypeIfcSlabTypeEnum[0:1] 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.
X
IfcSlabStandardCase
Definitions applying to Bridge View

 Instance diagram


Slabs are used to represent surfaces with primary function of vertical surface loading. The general definition IfcSlab defines a fixed shape, while the subtype IfcSlabStandardCase allows for parametric resizing.

Concept usage

Material Layer Set Usage

The Material Layer Set Usage concept applies to this entity.

Multi-layer slabs can be represented by refering to several IfcMaterialLayer's within the IfcMaterialLayerSet that is referenced from the IfcMaterialLayerSetUsage

Material information can also be given at the IfcSlabType, defining the common attribute data for all occurrences of the same type. It is then accessible by the inverse IsDefinedBy relationship pointing to IfcSlabType.HasAssociations and via IfcRelAssociatesMaterial.RelatingMaterial. The IfcSlabStandardCase defines in addition that the IfcSlabType should have a unique IfcMaterialLayerSet, that is referenced by the IfcMaterialLayerSetUsage assigned to all occurrences of this IfcSlabType.

 

Material layer set and usage
EXAMPLE  Figure 199 illustrates assignment of IfcMaterialLayerSetUsage and IfcMaterialLayerSet to the IfcSlabStandardCase as the slab occurrence and to the IfcSlabType. The same IfcMaterialLayerSet shall be shared by many occurrences of IfcMaterialLayerSetUsage. This relationship shall be consistent to the relationship between the IfcSlabType and the IfcSlabStandardCase.

Figure 199 — Slab type definition

 

Figure 200 illustrates slab material usage, where the following conventions shall be met:

  • The reference coordinate system is the coordinate system established by the IfcExtrudedAreaSolid.Position.
  • The reference plane is the plane defined by the extruded profile of IfcExtrudedAreaSolid.SweptSolid. The IfcMaterialLayerSetUsage.OffsetFromReferenceLine is given as a distance from this plane.
  • The IfcMaterialLayerSetUsage.DirectionSense defines how the IfcMaterialLayer's are assigned to the reference plane. POSITIVE means in direction to the positive z-axis of the reference coordinate system.
  • The IfcMaterialLayerSetUsage.OffsetFromReferenceLine is the distance parallel to the reference plane and always perpendicular to the base (XY) plane of the reference coordinate system. This is independent of a potential non-perpendicular extrusion given by IfcExtrudedAreaSolid.ExtrudedDirection <> 0.,0.,1. A positive value of IfcMaterialLayerSetUsage.OffsetFromReferenceLine would then point into the positive z-axis of the reference coordinate system.
  • The Thickness of each IfcMaterialLayer shall be the parallel distance (measured perpendicular to the base plane). The TotalThickness of the IfcMaterialLayerSet is the sum of all layer thicknesses and in case of a perpendicular extrusion identical with IfcExtrudedAreaSolid.Depth
  • The IfcMaterialLayerSetUsage.LayerSetDirection is always AXIS3.
slab material layer set
roof slab material layer set

Figure 200 — Slab material layers

Exchange
Import R
Export R


Concept inheritance

#ConceptModel View
IfcRoot
Software IdentityBridge View
User IdentityBridge View
Object OwnershipBridge View
IfcObject
Property Sets for ObjectsBridge View
IfcElement
Element Occurrence AttributesBridge View
Product Local PlacementBridge View
Product AssignmentBridge View
IfcSlab
Object TypingBridge View
Quantity SetsBridge View
Material Profile SetBridge View
Constraint AssociationBridge View
Element DecompositionBridge View
Element PositioningBridge View
Structural Surface AssignmentBridge View
Body SweptSolid Extruded Arbitrary GeometryBridge View
Body AdvancedSwept Fixed Reference GeometryBridge View
Body AdvancedSwept Surface Curve GeometryBridge View
Body Spine GeometryBridge View
IfcSlabStandardCase
Material Layer Set UsageBridge View
Formal representations
XSD Specification
 <xs:element name="IfcSlabStandardCase" type="ifc:IfcSlabStandardCase" substitutionGroup="ifc:IfcSlab" nillable="true"/>
 <xs:complexType name="IfcSlabStandardCase">
  <xs:complexContent>
   <xs:extension base="ifc:IfcSlab"/>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcSlabStandardCase
 SUBTYPE OF (IfcSlab);
 WHERE
  HasMaterialLayerSetusage : SIZEOF (QUERY(temp <* USEDIN(SELF, 'IFCKERNEL.IFCRELASSOCIATES.RELATEDOBJECTS') | ('IFCPRODUCTEXTENSION.IFCRELASSOCIATESMATERIAL' IN TYPEOF(temp)) AND ('IFCMATERIALRESOURCE.IFCMATERIALLAYERSETUSAGE' IN TYPEOF(temp.RelatingMaterial)) )) = 1;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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