 | Gruppe (allgemein) |
 | Group |
 | Groupe |
| Item | SPF | XML | Change | Description | IFC2x3 to IFC4 4.0.0.0 |
|---|---|---|---|---|
| IfcGroup | ||||
| OwnerHistory | MODIFIED | Instantiation changed to OPTIONAL. |
IfcGroup is an generalization of any arbitrary group. A group is a logical collection of objects. It does not have its own position, nor can it hold its own shape representation. Therefore a group is an aggregation under some non-geometrical / topological grouping aspects.
EXAMPLE An example for a group is a system, since it groups elements under the aspect of their role, regardless of their position in a building. One of the most important usage of a group representing a system is the IfcDistributionSystem, that groups distribution components, such as space heaters and valves into a heating system.
A group can hold any collection of objects, the relationship IfcRelAssignsToGroup is used to establish the group collection. Objects within a group are products, processes, controls, resources, actors or other groups, thus groups can be nested. An object can be part of zero, one, or many groups. Grouping relationships are not required to be hierarchical nor do they imply a dependency.
Groups are assigned to other objects (such as a process or a resource) by the relationship object that refers to the corresponding object:
A group can be exchanged without having already objects within the group collection.
IfcGroup does not define an own object coordinate system, nor does it have an independent shape representation.
NOTE Use IfcRelAggregates together with the appropriate subtypes of IfcProduct to define an aggregation of products that may have its own position and shape representation. This relationship shall be used to create a product breakdown structure.
HISTORY New entity in IFC1.0.
IFC4 CHANGE The inverse IsGroupedBy relationship is set to 0..n
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IsGroupedBy | IfcRelAssignsToGroup @RelatingGroup | S[0:?] | Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.
IFC4 CHANGE The cardinality has been changed from 1..1 to 0..? in order to allow the exchange of a group concept without having already group members assigned. It now also allows the use of many instances of IfcRelAssignsToGroup to assign the group members. The change has been done with upward compatibility for file based exchange. | X | |
| ReferencedInStructures | IfcRelReferencedInSpatialStructure @RelatedElements | S[0:?] | Reference to the relationship IfcRelReferencedInSpatialStructure that relates the group to a spatial element. | X |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcRoot | |||||
| 1 | GlobalId | IfcGloballyUniqueId | Assignment of a globally unique identifier within the entire software world. | X | |
| 2 | OwnerHistory | 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,
NOTE only the last modification in stored - either as addition, deletion or modification. IFC4 CHANGE The attribute has been changed to be OPTIONAL. | X |
| 3 | Name | IfcLabel | ? | 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 | ? | Optional description, provided for exchanging informative comments. | X |
| IfcObjectDefinition | |||||
| HasAssignments | IfcRelAssigns @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 | |
| Nests | IfcRelNests @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).
IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition. | X | |
| IsNestedBy | IfcRelNests @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).
IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition. | X | |
| HasContext | IfcRelDeclares @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.
IFC4 CHANGE The inverse attribute datatype has been added. | X | |
| IsDecomposedBy | IfcRelAggregates @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).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| Decomposes | IfcRelAggregates @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).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | 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 | ? | 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 |
| IsDeclaredBy | IfcRelDefinesByObject @RelatedObjects | 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.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| Declares | IfcRelDefinesByObject @RelatingObject | 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.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| IsTypedBy | IfcRelDefinesByType @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.
IFC4 CHANGE New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange. | X | |
| IsDefinedBy | IfcRelDefinesByProperties @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.
IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange. | X | |
| IfcGroup | |||||
| IsGroupedBy | IfcRelAssignsToGroup @RelatingGroup | S[0:?] | Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.
IFC4 CHANGE The cardinality has been changed from 1..1 to 0..? in order to allow the exchange of a group concept without having already group members assigned. It now also allows the use of many instances of IfcRelAssignsToGroup to assign the group members. The change has been done with upward compatibility for file based exchange. | X | |
| ReferencedInStructures | IfcRelReferencedInSpatialStructure @RelatedElements | S[0:?] | Reference to the relationship IfcRelReferencedInSpatialStructure that relates the group to a spatial element. | X | |
Group Assignment
The Group Assignment concept applies to this entity.
The IfcGroup establishes an arbitrary collection of objects through utilizing this concept.
Instance diagram
<?xml version="1.0" encoding="utf-8"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="c5090377-d50c-4133-b6d0-b854fbbcc812" name="IfcGroup" applicableRootEntity="IfcGroup">
<Applicability>
<Template ref="9562c35c-f206-4a48-8675-8687fe1d7ed0" />
<TemplateRules operator="and">
</TemplateRules>
</Applicability>
<Concepts>
<Concept uuid="a17883eb-0b16-4ab3-b2d5-77cafa455ac8" name="Group Assignment">
<Template ref="f567967f-5493-44d9-ac51-937c09ac2583" />
</Concept>
</Concepts>
</ConceptRoot>
| # | Concept | Template | Model View |
|---|---|---|---|
| IfcRoot | |||
| Identity | Software Identity | General Usage | |
| Revision Control | Revision Control | General Usage | |
| IfcObjectDefinition | |||
| Classification Association | Classification Association | General Usage | |
| Assignment to Product | Assignment to Product | General Usage | |
| IfcObject | |||
| Object User Identity | Object User Identity | General Usage | |
| Object Predefined Type | Object Predefined Type | General Usage | |
| Object Typing | Object Typing | General Usage | |
| Property Sets for Objects | Property Sets for Objects | General Usage | |
| Property Sets with Override | Property Sets with Override | General Usage | |
| IfcGroup | |||
| Group Assignment | Group Assignment | General Usage | |
ENTITY IfcGroup
SUPERTYPE OF(ONEOF(IfcAsset, IfcInventory, IfcStructuralLoadGroup, IfcStructuralResultGroup, IfcSystem))
SUBTYPE OF (IfcObject);
INVERSE
IsGroupedBy : SET [0:?] OF IfcRelAssignsToGroup FOR RelatingGroup;
ReferencedInStructures : SET [0:?] OF IfcRelReferencedInSpatialStructure FOR RelatedElements;
END_ENTITY;
References: IfcRelAssignsToGroup
IfcSpatialReferenceSelect
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