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.
One or several instances of subtypes of IfcElementComponent should always be accompanied by a defining instance of a respective subtype of IfcElementComponentType. The type object holds shape and material information.
HISTORY New entity in IFC2x2
It is often desirable to model a number of same-shaped element components by means of a single occurrence object, e.g. several bolts within a connection or a row of reinforcement elements. In this IFC release, this is possible by means of multiple mapped representation as documented below.
To express the multiplicity of element components also on a higher semantic level, a Qto_ElementComponentPatternQuantities should be provided via IfcRelDefinesByProperties and contain the number of pieces which are placed by a single IfcElementComponent instance.
A symbolic representation is defined for a row of components or several rows of components within a single instance of IfcElementComponent. Such rows or arrays may contain possibly large numbers of individual pieces. The product definition shape consists of an IfcShapeRepresentation with the attribute values
and one or several curves as geometric items. The curves represent where reference points of the pieces are located. For example, such reference points may be at the heads of mechanical fasteners or at the starting point of the extrusion axis of reinforcement bars. In case of straight components (bolts, nails, staples, straight reinforcement bars, or similar), the local placement of the IfcElementComponent shall be located and oriented such that the local z axis is parallel with the axes of the components. A Qto_ElementComponentPatternQuantities should denote the count of pieces in the row or array and their spacing.
|1||GlobalId||IfcGloballyUniqueId||[1:1]||Assignment of a globally unique identifier within the entire software world.||X|
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.
|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|
|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|
|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).||X|
|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|
|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.||X|
|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|
|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|
|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|
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.
|S[0:1]||Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.||X|
|S[0:?]||Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.||X|
|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|
|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|
|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|
|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|
|8||Tag||IfcIdentifier||[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|
|S[0:1]||Reference to the IfcRelFillsElement Relationship that puts the element as a filling into the opening created within another element.||X|
|S[0:?]||Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to.||X|
|S[0:?]||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.
|S[0:?]||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.
|S[0:?]||Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement.||X|
|S[0:?]||Reference relationship to the spatial structure element, to which the element is additionally associated. This relationship may not be hierarchical, an element may be referenced by zero, one or many spatial structure elements.||X|
|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|
|S[0:?]||Reference to the connection relationship with realizing element. The relationship, if provided, assigns this element as the realizing element to the connection, which provides the physical manifestation of the connection relationship.||X|
|S[0:?]||Reference to space boundaries by virtue of the objectified relationship IfcRelSpaceBoundary. It defines the concept of an element bounding spaces.||X|
|S[0:?]||Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element.||X|
|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.||X|
|S[0:?]||Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversBldgElement. It defines the concept of an element having coverings associated.||X|
Property Sets for Objects
The Property Sets for Objects concept applies to this entity as shown in Table 226.
Table 226 — IfcElementComponent Property Sets for Objects
The Mapped Geometry concept applies to this entity.
The mapped item, IfcMappedItem, should be used if appropriate as it allows for reusing the geometry definition of a type at all occurrences of the same type.
A single instance of a subtype of IfcElementComponent can stand for several actual element components at once. In this case, the IfcShapeRepresentation contains as many mapped items as there are element components combined within this occurrence object.
EXAMPLE Figure 263 illustrates multiple components modeled as a single occurrence object (here: IfcFastener)
Figure 263 — Element component mapped representation
Representation identifier and type are the same as in single mapped representation. The number of mapped items in the representation corresponds with the count of element components in the IfcElementQuantity.
|Software Identity||Common Use Definitions|
|Revision Control||Common Use Definitions|
|Object Occurrence Predefined Type||Common Use Definitions|
|Product Local Placement||Common Use Definitions|
|Box Geometry||Common Use Definitions|
|FootPrint Geometry||Common Use Definitions|
|Body SurfaceOrSolidModel Geometry||Common Use Definitions|
|Body SurfaceModel Geometry||Common Use Definitions|
|Body Tessellation Geometry||Common Use Definitions|
|Body Brep Geometry||Common Use Definitions|
|Body AdvancedBrep Geometry||Common Use Definitions|
|Body CSG Geometry||Common Use Definitions|
|Mesh Geometry||Common Use Definitions|
|Property Sets for Objects||Common Use Definitions|
|Mapped Geometry||Common Use Definitions|
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