Instantiation of Model Structures
Change History
| Id | Subject | Date |
| Latest Commit | Instantiate what the context needs, not complete structures (#1172) | 2026-09-28 |
| #1172 | Replaced the completeness requirement by the instantiation of context relevant elements | 2026-09-28 |
| KBLFRM-1191 | Extracted information from PSI recommendation and extended it where necesseray. | 2024-03-14 |
There are various locations in the VEC model where structures / patterns are defined
and used / instantiated somewhere else (e.g. a connector with its slots and cavities).
In most cases, the elements in the definition of a structure have corresponding
elements in the instancing (e.g. ConnectorHousingSpecification →
ConnectorHousingRole, Slot → SlotReference & Cavity → CavityReference).
Scope of Instantiation
Following the principle of optionality in the VEC, a defined structure does not have to be
instantiated completely. Only the elements that are required for the definition of the
respective context need to be instantiated. An element is required if the context makes a
statement about it, for example a context specific identifier or description, a redefined
technical property, a placement, a routing or a contacting. For example, a
CavityReference is required for a Cavity that is contacted
in the harness, but not for a cavity about which the harness does not state anything.
Where an instantiation element exists, it shall reference the element of the structural
definition it instantiates (e.g. referencedCavity of a CavityReference,
referencedWireElement of a WireElementReference or
partStructureSpecification of a PartWithSubComponentsRole). For the
instantiation of library parts (e.g. assemblies), each instantiated occurrence shall
additionally reference its origin in the part master definition (instanciatedOccurrence /
instanciatedUsage, see Composite Parts).
This applies to all instantiated structures, for example connectors, wires, E/E components and
composite parts (assemblies, modules). The same principle applies to the creation of
Roles (see Instantiation with Roles)
and to the description of parts with specifications (see
Content Requirements).
Absence of Instantiation Elements
As a consequence, the absence of an instantiation element has no meaning of its own. A missing
CavityReference means “no statement about this cavity in this context”, and
not “this cavity is unused”. The same applies to SlotReference,
WireElementReference, HousingComponentReference and all
other instantiation elements. A reading system shall not interpret the absence of an
instantiation element as a statement about the product.