IfcElement

Natural language names
deElement (allgemein)
enElement
frÉlément
Semantic definitions at the entity
Entity definition

An element is a generalization of all components that make up an AEC product.

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.

The 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. 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
Attribute definitions
#AttributeTypeCardinalityDescription B
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
Inherited definitions from supertypes
Entity inheritance IfcBuildingElement IfcCivilElement IfcDistributionElement IfcElementAssembly IfcElementComponent IfcFeatureElement IfcGeographicElement 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
Definitions applying to Bridge View

 Instance diagram

Concept usage

Element Occurrence Attributes

The Element Occurrence Attributes concept applies to this entity.

Exchange
Import O
Export O


Product Local Placement

The Product Local Placement concept applies to this entity as shown in Table 14.

TypeRelativeDescription
IfcLocalPlacementIfcLocalPlacementRelative placement according to position and rotation relative to container.
IfcLocalPlacementAbsolute placement according to position and rotation of world coordinate system.

Table 14 — IfcElement Product Local Placement

The object placement for any subtype of IfcElement is defined by the IfcObjectPlacement, either IfcLocalPlacement or IfcGridPlacement, which defines the local object coordinate system that is referenced by all geometric representations of that IfcElement.

Exchange
Import R
Export R


Product Assignment

The Product Assignment concept applies to this entity as shown in Table 15.

TypeDescription
IfcTaskTasks assigned to bridge components indicating applicable construction phases

Table 15 — IfcElement Product Assignment

Exchange
Import O
Export O


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
Formal representations
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:attribute name="Tag" type="ifc:IfcIdentifier" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcElement
 ABSTRACT SUPERTYPE OF(ONEOF(IfcBuildingElement, IfcCivilElement, IfcDistributionElement, IfcElementAssembly, IfcElementComponent, IfcFeatureElement, IfcGeographicElement))
 SUBTYPE OF (IfcProduct);
  Tag : OPTIONAL IfcIdentifier;
 INVERSE
  ConnectedTo : SET OF IfcRelConnectsElements FOR RelatingElement;
  HasOpenings : SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
  ConnectedFrom : SET OF IfcRelConnectsElements FOR RelatedElement;
  ContainedInStructure : SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
  PositionedFrom : SET [0:1] OF IfcRelPositions FOR RelatingElement;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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