What is a hierarchy root element?

A root element is the model or object that is used as the top-level element in the hierarchy you have defined. This element is displayed when you open the hierarchy in the portal.

If you want to use a specific item from an ARIS database as the top-level hierarchy element, for example, a specific model or object, this must be defined as the root element. You require the GUID, which you can copy from the Properties dialog for the model or object in ARIS Architect, for example.