In certain processing, you need to have a set of objects and links around the object that interests you, and this object will be referred to as the "root object". Depending on the context, description of this set can vary by taking into account certain objects or not, certain link types or not.

 

To solve this problem, the perimeter object has been installed. At the technical level, this is an occurrence of the "Operator" MetaClass, of which the "_OpNature" MetaAttribute is positioned on "Compound".