Definition from buildingSMART: The assignment relationship,
IfcRelAssigns, is a generalization of "link" relationships among
instances of IfcObject and its various 1st level subtypes. A link
denotes the specific association through which one object (the client) applies
the services of other objects (the suppliers), or through which one object may
navigate to other objects.
The client is denoted as the relating object and is established at the
level of the specific, instantiable subtypes of IfcRelAssigns. The
suppliers are denoted as the related objects and they are established by the
NOTE: The terms "client" and "supplier" are
used in a general concept and do not imply any meaning for implementations of
systems (like client-server).
EXAMPLE: A resource may receive information
about its nature of representing real building products by establishing a link
between IfcResource and IfcBuildingElement (subtype of
IfcProduct) throught he assignment relationship
IfcRelAssignsToResource. The resource is then the client that applies
the services of other objects (here building elements) to express the
particular view of elements to be consumed as a resource in a
The assignment relationship establishs a bi-directional relationship
among the participating objects and does not imply any dependency. The subtypes
of IfcRelAssigns establishes the particular semantic meaning of the assignment
HISTORY: New entity in IFC Release
| Related objects, which are assigned to a single object. The type of the single (or relating) object is
defined in the subtypes of IfcRelAssigns.
| Particular type of the assignment relationship. It can constrain the applicable object types, used within
the role of RelatedObjects.
| Rule checks whether the types of the assigned related objects comply with the contraint given by the
RelatedObjectsType. The rule is important for constraint checks at subtypes of IfcRelAssigns or at subtypes
of IfcObject, which refers to assignment relationships through the inverse HasAssignments relation.