IfcSlabType

BACnet MVD

#### IfcSlabType

Natural language names

| Decke / Dachfläche / Bodenplatte - Typ
| Slab Type
| Type de dalle

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcSlabType |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.
ApplicableOccurrence |  |  | MODIFIED | Type changed from IfcLabel to IfcIdentifier.

##### Semantic definitions at the entity

Entity definition

The element type IfcSlabType defines commonly shared information for occurrences of slabs. The set of shared information may include:

- common properties within shared property sets
- common material information
- common material layer definitions
- common shape representations

> NOTE It is illegal to share shape representations as representation maps for occurrences of IfcSlabStandardCase.

It is used to define a slab specification (i.e. the specific product information, that is common to all occurrences of that product type). Slab types may be exchanged without being already assigned to occurrences.

> NOTE The product representations are defined as representation maps (at the level of the supertype IfcTypeProduct, which gets assigned by an element occurrence instance through the IfcShapeRepresentation.Item[1] being an IfcMappedItem.

The occurrences of the IfcSlabType within building models are represented by instances of IfcSlabStandardCase if the IfcSlabType has a single associated IfcMaterialLayerSet; otherwise they are represented by instances of IfcSlab, or IfcSlabElementedCase.

> HISTORY New entity in IFC2x2.

Informal Propositions:

1. The material assignment, if provided using the IfcRelAssociatesMaterial relationship, shall not reference the IfcMaterialLayerSetUsage.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
10 | PredefinedType | IfcSlabTypeEnum |  | Identifies the predefined types of a slab element from which the type required may be set. | X | X

Formal Propositions

Rule | Description
--- | ---
CorrectPredefinedType | The inherited attribute ElementType shall be provided, if the PredefinedType is set to USERDEFINED.

##### 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
IfcTypeObject

5

ApplicableOccurrence

IfcIdentifier

?

The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable. The following conventions are used:

- The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix
- It can be optionally followed by the predefined type after the separator "/" (forward slash), using uppercase
- If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "," forming a comma separated string.

> EXAMPLE Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'.

X

6

HasPropertySets

IfcPropertySetDefinition

? S[1:?]

Set list of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.

> IFC2x3 CHANGE The attribute aggregate type has been changed from LIST to SET.

X

X

| Types | IfcRelDefinesByType @RelatingType | S[0:1] | Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type. |  | X
IfcTypeProduct
7 | RepresentationMaps | IfcRepresentationMap | ? L[1:?] | List of unique representation maps. Each representation map describes a block definition of the shape of the product style. By providing more than one representation map, a multi-view block definition can be given. | X | X
8 | Tag | IfcLabel | ? | The tag (or label) identifier at the particular type of a product, e.g. the article number (like the EAN). It is the identifier at the specific level. |  | 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 type.

> IFC4 CHANGE New inverse relationship.

X

IfcElementType
9 | ElementType | 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
IfcBuildingElementType
IfcSlabType
10 | PredefinedType | IfcSlabTypeEnum |  | Identifies the predefined types of a slab element from which the type required may be set. | X | X

##### Definitions applying to Design Transfer View

Instance diagram

#####

Slab types may be described at several levels of detail to support the following slab occurrences:

- IfcSlab: Explicit geometry instantiated in exact form at occurrences.
- IfcSlabStandardCase: Implicit material layers filling boundary ('FootPrint' representation) defined at occurrences.
- IfcSlabElementedCase: implicit material layers and corresponding aggregated parts filling each layer.

As shown in Figure 234, each material layer may be elaborated into an element (where the Name matches exactly), and each element may be defined by its own type, which may be further elaborated by material layers and/or parts. The LayerThickness of IfcMaterialLayer must be derived from the corresponding element as follows:

- if element does not have a type, then the thickness must be regarded as 0 (supporting scenario where a particular configuration may have one side a wall unfinished)
- if element has a material layer set, then it must equal the total thickness of the element's material layer set
- if element has a material profile set, then it must equal the total thickness of the element's material profile set
- if element is decomposed into parts (such as IfcElementAssemblyType for slab framing), then it must equal the bounding extent of the parts according to the layer set direction - if parts do not have representations, then such thickness is calculated according to the material layers or profiles.

Figure 234 — Slab type

Concept usage

Material Layer Set

The Material Layer Set concept applies to this entity.

The material of the IfcSlabType is defined by the IfcMaterialLayerSet or as fall back by IfcMaterial and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship.

> NOTE It is illegal to assign an IfcMaterial to an IfcSlabType, if there is at least one occurrences. of IfcSlabStandardCase for this type.

The shared material layer set definition is defined by assigning an IfcMaterialLayerSet (see material use definition above). The IfcMaterialLayer refers to one or several of IfcMaterial that is the common for all slab occurrence, if used. It is only applicable if the IfcSlabType has only occurrences of type IfcSlabStandardCase (see definition of IfcSlabStandardCase for further information).

> NOTE Since each individual instance of IfcSlabStandardCase defines its own IfcMaterialLayerSetUsage including the offset from the reference plane, the same IfcSlabType can be used independently of the reference plane alignment of its occurrences.

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="14eda651-97c1-4571-8496-be3538999c20" name="IfcSlabType" status="sample" applicableRootEntity="IfcSlabType">
<Concepts>
<Concept uuid="6c178501-b085-4d01-8ed7-1dd80f4db792" name="Material Layer Set" status="sample" override="false">
<Template ref="dfb5b3a9-50e3-46e2-8518-1f03e7cfd886" />
<Requirements>
<Requirement applicability="export" requirement="recommended" exchangeRequirement="c498680d-cc8b-4032-a9f3-cc6b2f096f42" />
<Requirement applicability="import" requirement="recommended" exchangeRequirement="c498680d-cc8b-4032-a9f3-cc6b2f096f42" />
</Requirements>
</Concept>
</Concepts>
</ConceptRoot>
`
Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View
IfcTypeObject
| Library Association | Library Association | Design Transfer View
IfcElementType
| Material Constituents | Material Constituent Set | Design Transfer View
| Material Single | Material Single | Design Transfer View
| Type Body CSG Geometry | Type Body CSG Geometry | Design Transfer View
| Type Body Brep Geometry | Type Body Brep Geometry | Design Transfer View
| Type Body AdvancedBrep Geometry | Type Body AdvancedBrep Geometry | Design Transfer View
| Element Type Aggregation | Type Element Aggregation | Design Transfer View
| Property Sets for Types | Property Sets for Types | Design Transfer View
IfcSlabType
| Material Layer Set | Material Layer Set | Design Transfer View

##### Definitions applying to BACnet View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View
IfcTypeObject
| Library Association | Library Association | Design Transfer View
IfcElementType
| Material Constituents | Material Constituent Set | Design Transfer View
| Material Single | Material Single | Design Transfer View
| Type Body CSG Geometry | Type Body CSG Geometry | Design Transfer View
| Type Body Brep Geometry | Type Body Brep Geometry | Design Transfer View
| Type Body AdvancedBrep Geometry | Type Body AdvancedBrep Geometry | Design Transfer View
| Element Type Aggregation | Type Element Aggregation | Design Transfer View
| Property Sets for Types | Property Sets for Types | Design Transfer View
IfcSlabType
| Material Layer Set | Material Layer Set | Design Transfer View

##### Examples

- Slab standard case

##### Formal representations

XML Specification
`<xs:element name="IfcSlabType" type="ifc:IfcSlabType" substitutionGroup="ifc:IfcBuildingElementType" nillable="true"/>
<xs:complexType name="IfcSlabType">
<xs:complexContent>
<xs:extension base="ifc:IfcBuildingElementType">
<xs:attribute name="PredefinedType" type="ifc:IfcSlabTypeEnum" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcSlabType
SUBTYPE OF (IfcBuildingElementType);
PredefinedType : IfcSlabTypeEnum;
WHERE
CorrectPredefinedType : (PredefinedType <> IfcSlabTypeEnum.USERDEFINED) OR
((PredefinedType = IfcSlabTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcElementType.ElementType));
END_ENTITY;

EXPRESS-G diagram

`

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