#### IfcElementComponent

Natural language names

##### Semantic definitions at the entity

Entity definition

An element component is a representation for minor items included in, added to or connecting to or between elements, which usually are not of interest from the overall building structure viewpoint. However, these small parts may have vital and load carrying functions within the construction. These items do not provide any actual space boundaries. Typical examples of IfcElementComponents include different kinds of fasteners and various accessories.

> HISTORY New entity in IFC Release 2x2

Geometry Use Definitions:

The geometric representation of IfcElementComponent is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are:

Local Placement
The local placement for IfcElementComponent is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.

- The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcElement or IfcElementAssembly, which is used in the Decomposes inverse attribute, i.e. the local placement is defined relative to the local placement of the element or element assembly in which the component is contained.
- If the relative placement is not used, the absolute placement is defined within the world coordinate system.

Surface Model Representation
Any IfcElementComponent (if no further constraints are defined at the level of its subtypes) may be represented as a single or multiple surface models, based on either shell or face based models. It is ensured by assigning the value 'SurfaceModel' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape.

Brep Representation
Any IfcElementComponent (if no further constraints are defined at the level of its subtypes) may be represented as a single or multiple Boundary Representation elements (which are restricted to faceted Brep with or without voids). The Brep representation allows for the representation of complex element shape. It is ensured by assigning the value 'Brep' to the RepresentationType attribute of IfcShapeRepresentation. In some cases it may be useful to also expose a simple representation as a bounding box representation of the same complex shape.

Mapped Representation
The mapped item, IfcMappedItem, should be used if appropriate as it allows for reusing the geometry definition of the equipment type at occurrences of the same equipement type. In this case the IfcShapeRepresentation.RepresentationType = 'MappedRepresentation' is used.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId | [1:1] | Assignment of a globally unique identifier within the entire software world. | X
2 | OwnerHistory | IfcOwnerHistory | [1:1] | 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. | 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
| IsDecomposedBy | IfcRelDecomposes @RelatingObject | S[0:?] | Reference to the decomposition relationship, that allows this object to be the composition of other objects. An object can be decomposed by several other objects. | X
| Decomposes | IfcRelDecomposes @RelatedObjects | S[0:1] | References to the decomposition relationship, that allows this object to be a part of the decomposition. An object 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
IfcObject
5 | ObjectType | IfcLabel | [0:1] | 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
| IsDefinedBy | IfcRelDefines @RelatedObjects | S[0:?] | Set of relationships to type or property (statically or dynamically defined) information that further define the object. In case of type information, the associated IfcTypeObject contains the specific information (or type, or style), that is common to all instances of IfcObject referring to the same type. | X
IfcProduct
6 | ObjectPlacement | IfcObjectPlacement | [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
7 | Representation | IfcProductRepresentation | [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
IfcElement
8 | Tag | - |  | This attribute is out of scope for this model view definition and shall not be set. |
| ConnectedTo | IfcRelConnectsElements @RelatingElement | S[0:?] | Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to. |
| HasOpenings | IfcRelVoidsElement @RelatingBuildingElement | S[0:?] | Reference to the Voids Relationship that creates an opening in an element. An element can incorporate zero-to-many openings. | X
| IsConnectionRealization | IfcRelConnectsWithRealizingElements @RealizingElements | S[0:?] | Reference to the connection relationship with realizing element. The relationship then refers to the realizing element which provides the physical manifestation of the connection relationship. | X
| ConnectedFrom | IfcRelConnectsElements @RelatedElement | S[0:?] | Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element. | X
| ContainedInStructure | IfcRelContainedInSpatialStructure @RelatedElements | S[0:1] | Containment relationship to the spatial structure element, to which the element is primarily associated. | X
IfcElementComponent

##### Formal representations

XSD Specification
`<xs:element name="IfcElementComponent" type="ifc:IfcElementComponent" abstract="true" substitutionGroup="ifc:IfcElement" nillable="true"/>
<xs:complexType name="IfcElementComponent" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcElement"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcElementComponent
ABSTRACT SUPERTYPE OF(ONEOF(IfcDiscreteAccessory, IfcFastener))
SUBTYPE OF (IfcElement);
END_ENTITY;

EXPRESS-G diagram

`

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