#### 5.4.3.6 IfcElement

| Élément
| Element (allgemein)

An element is a generalization of all components that make up an AEC product. Those elements can be logically contained by a spatial structure element that constitutes a certain level within a project structure hierarchy (site, building, storey or space). This is done by using the IfcRelContainedInSpatialStructure relationship.

Elements are physically existent objects, although they might be void elements, such as holes. Elements either remain permanently in the AEC product, or only temporarily, as formwork does. Elements can be either assembled on site or pre-manufactured and built in on site.

> EXAMPLE Examples of elements in a building construction context are walls, floors, windows and recesses.

An element can have material and quantity information assigned through the IfcRelAssociatesMaterial and IfcRelDefinesByProperties relationship.

In addition an element can be declared to be a specific occurrence of an element type (and thereby be defined by the element type properties) using the IfcRelDefinesByType relationship.

An element can also be defined as an element assembly that is a group of semantically and topologically related elements that form a higher level part of the AEC product. Those element assemblies are defined by virtue of the IfcRelAggregates relationship.

> EXAMPLE Examples for element assembly are complete Roof Structures, made by several Roof Areas, or a Stair, composed by Flights and Landings.

Elements that performs the same function may be grouped by an "Element Group By Function". It is realized by an instance of IfcGroup with the ObjectType = 'ElementGroupByFunction".

> HISTORY New entity in IFC1.0

Quantity Use Definition

The quantities relating to the IfcElement are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. A detailed specification for individual quantities is introduced at the level of subtypes of IfcElement.

Geometry Use Definitions

The geometric representation of any IfcElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. A detailed specification for the local placement and shape representaion is introduced at the level of subtypes of IfcElement.

XSD Specification:

<xs:element name="IfcElement" type="ifc:IfcElement" abstract="true" substitutionGroup="ifc:IfcProduct" nillable="true"/>
<xs:complexType name="IfcElement" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcProduct"/>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcElement

| ABSTRACT SUPERTYPE OF(ONEOF(IfcBuildingElement, IfcDistributionElement, IfcElementComponent, IfcTransportElement))

| SUBTYPE OF (IfcProduct);

Tag | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsInterferedByElements | : | SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements | : | SET OF IfcRelInterferesElements FOR RelatingElement;
ContainedInStructure | : | SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;

END_ENTITY;

Attribute Definitions:

Tag | : | 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.
IsInterferedByElements | : | 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.
InterferesElements | : | 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.
ContainedInStructure | : | 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.

Inheritance Graph:

ENTITY IfcElement

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcObjectDefinition

| INVERSE

HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
Nests | : | SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy | : | SET OF IfcRelNests FOR RelatingObject;
HasContext | : | SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy | : | SET OF IfcRelAggregates FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;

| ENTITY IfcObject

ObjectType | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsDeclaredBy | : | SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares | : | SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy | : | SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy | : | SET OF IfcRelDefinesByProperties FOR RelatedObjects;

| ENTITY IfcProduct

ObjectPlacement | : | OPTIONAL IfcObjectPlacement;
Representation | : | OPTIONAL IfcProductRepresentation;

| INVERSE

ReferencedBy | : | SET OF IfcRelAssignsToProduct FOR RelatingProduct;

| ENTITY IfcElement

Tag | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsInterferedByElements | : | SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements | : | SET OF IfcRelInterferesElements FOR RelatingElement;
ContainedInStructure | : | SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;

END_ENTITY;

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