IfcElementAssemblyType

Item	SPF	XML	Change	Description
IFC2x3 to IFC4
IfcElementAssemblyType			ADDED

Semantic definitions at the entity

Entity definition

The IfcElementAssemblyType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).

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.

An element assembly type is used to define the common properties of a certain type of an element assembly that may be applied to many instances of that type to assign a specific style. An element assembly types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences.

The occurrences of the IfcElementAssemblyType are represented by instances of IfcElementAssembly.

HISTORY New entity in IFC4.

Attribute definitions

#	Attribute	Type	Cardinality	Description	B
10	PredefinedType	IfcElementAssemblyTypeEnum	[1:1]	Predefined types to define the particular type of the transport element. There may be property set definitions available for each predefined type.	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	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[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
3	Name	IfcLabel	[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
4	Description	IfcText	[0:1]	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).
	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).	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.
	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).	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).	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
IfcTypeObject
5	ApplicableOccurrence	-		This attribute is out of scope for this model view definition and shall not be set.
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.	X
	Types	IfcRelDefinesByType @RelatingType	S[0:1]	Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.
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
8	Tag	-		This attribute is out of scope for this model view definition and shall not be set.
	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.
IfcElementType
9	ElementType	-		This attribute is out of scope for this model view definition and shall not be set.
IfcElementAssemblyType
10	PredefinedType	IfcElementAssemblyTypeEnum	[1:1]	Predefined types to define the particular type of the transport element. There may be property set definitions available for each predefined type.	X

Definitions applying to Bridge View

Instance diagram

Templates for cross-framing between girders are defined using this definition.

Concept usage

Aggregation

The Aggregation concept applies to this entity as shown in Table 17.

PredefinedType	RelatedObjects	Description
	IfcMember	Members within the assembly.
	IfcPlate	Plates within the assembly.
	IfcElementComponent	Components within the assembly.

Table 17 — IfcElementAssemblyType Aggregation

The IfcElementAssembly shall represent an aggregate, i.e. it should have other elements, being subtypes of IfcElement, as contained (sub)parts. The table above only represents a selection of subtypes of IfcElement that are legitimate as parts in an IfcElementAssembly

The IfcElementAssembly is an aggregate i.e. being composed by other elements and acting as an assembly using the objectified relationship IfcRelAggregates, refering to it by its inverse attribute SELF\IfcObjectDefinition.IsDecomposedBy. Components of an assembly are described by instances of subtypes of IfcElement.
In this case, the contained subtypes of IfcElement shall not be additionally contained in the project spatial hierarchy, i.e. the inverse attribute SELF\IfcElement.ContainedInStructure of those IfcElement's shall be NIL.

Figure 158 illustrates spatial containment and element aggregation relationships.

Figure 158 — Element assembly containment

Exchange
Import	O	O
Export	O	O

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Bridge View
	User Identity	Bridge View
	Object Ownership	Bridge View
IfcTypeObject
	Property Sets for Types	Bridge View
IfcElementAssemblyType
	Aggregation	Bridge View

Formal representations

XSD Specification

 <xs:element name="IfcElementAssemblyType" type="ifc:IfcElementAssemblyType" substitutionGroup="ifc:IfcElementType" nillable="true"/>

 <xs:complexType name="IfcElementAssemblyType">

  <xs:complexContent>

   <xs:extension base="ifc:IfcElementType">

    <xs:attribute name="PredefinedType" type="ifc:IfcElementAssemblyTypeEnum" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcElementAssemblyType

 SUBTYPE OF (IfcElementType);

  PredefinedType : IfcElementAssemblyTypeEnum;

 WHERE

  CorrectPredefinedType : (PredefinedType <> IfcElementAssemblyTypeEnum.USERDEFINED) OR 
((PredefinedType = IfcElementAssemblyTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcElementType.ElementType));
END_ENTITY;

 EXPRESS-G diagram

Link to this page

	zusammengesetztes Element - Typ
	Element Assembly Type
	Type d'assemblage d'éléments