4.7.3 Group Assignment

Group Assignment established an arbitrary collection of objects within a group. The grouping relationship does not apply any other meaning then grouping objects under some aspect. It is non-hierarchical, that is objects can be grouped into different logical groups, and it does not interfere with other relationship concepts, such as ObjectAggregation.

The Group Assignment concept establish a given object as being the group collection for other objects. It usually implies the existence of a grouping relationship and the provision of some identity under which the group is characterized.

The group collection is handled by an instance of IfcRelAssignsToGroup, which assigns all group members to the IfcGroup being the collection.

NOTE  The IfcGroup maybe not yet have a grouping relationship established, it then identifies an empty group.
EXAMPLE  An air handler belonging to an air conditioning system is an example of such group assignment.

Figure 71 illustrates an instance diagram.

Group AssignmentIfcGroupIfcRelAssignsToGroupIfcProduct

Figure 71 — Group Assignment

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