An SMC structure relation is controlled using a relation definition that defines the various parameters for the adjustment and the structure treatments. When you create a structure relation, a relation definition is determined from the data in the structure relation and the rules defined in the settings and assigned to the structure relation. This assignment is fixed and is not changed even if the data or settings of the rules are changed.
In particular, the following data is controlled by the relation definition (non-exhaustive list):
The type itself and the type of validity to apply to the reference and cement structure.
Definition of whether new items are allowed in the target structure and whether all items of the reference must be installed in the target, taking into account the quantities of the items if necessary.
Defines which fields can be displayed and maintained.
Defines the checks and actions for new and deleted items, or changed field data.
Controls the lock or exclusion of substructures when maintaining the target structure.
Controls the numbering of the items.
Defines which error messages of checks that can be overridden by the user.