5.1.3.41 IfcRelNests
5.1.3.41.1 Semantic definition
The nesting relationship IfcRelNests is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The nesting relationship can be applied to all subtypes of objects and object types, such as processes, controls (e.g., cost items), and resources. It can also be applied to alignment, nesting its different layouts; and to physical subtypes of object and object types, such as elements having ports. The nesting implies an order among the nested parts.
Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The behaviour that is implied from the dependency has to be established inside the applications.
{ .change-ifc2x4}
5.1.3.41.2 Entity inheritance
5.1.3.41.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcRoot (4) | |||
| 1 | GlobalId | IfcGloballyUniqueId |
Assignment of a globally unique identifier within the entire software world. |
| 2 | OwnerHistory | OPTIONAL IfcOwnerHistory |
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. |
| 3 | Name | OPTIONAL IfcLabel |
An 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. |
| 4 | Description | OPTIONAL IfcText |
An optional description, provided to exchange informative comments. |
| Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes | |||
| IfcRelNests (2) | |||
| 5 | RelatingObject | IfcObjectDefinition |
The object definition, either an object type or an object occurrence, that represents the nest. It is the whole within the whole/part relationship. |
| 6 | RelatedObjects | LIST [1:?] OF IfcObjectDefinition |
The object definitions, either object type or object occurrence, that are being nested. They are defined as the parts in the ordered whole/part relationship - i.e. there is an implied order among the parts expressed by the position within the list of RelatedObjects. |
5.1.3.41.4 Formal propositions
| Name | Description |
|---|---|
| NoSelfReference |
The instance to which the relation points as provided by RelatingObject shall not be contained in the list of RelatedObjects. |
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5.1.3.41.5 Concept usage
| Concept | Usage | Description | |
|---|---|---|---|
| IfcRoot (2) | |||
| Revision Control | General |
Ownership, history, and merge state is captured using IfcOwnerHistory. |
|
| Software Identity | General |
IfcRoot assigns the globally unique ID. In addition, it may also provide a name and description for the concept. |
|
| Click to show 2 hidden inherited concepts Click to hide 2 inherited concepts | |||
5.1.3.41.6 Formal representation
ENTITY IfcRelNests
SUBTYPE OF (IfcRelDecomposes);
RelatingObject : IfcObjectDefinition;
RelatedObjects : LIST [1:?] OF IfcObjectDefinition;
WHERE
NoSelfReference : SIZEOF(QUERY(Temp <* RelatedObjects | RelatingObject :=: Temp)) = 0;
END_ENTITY;
