Vianova ID is used as an identification for QuadriDCM Easy Access. It is a unique, personal and global ID that makes you the same "person" on every project you use it for. It could be on an owner's Easy Access user list or at another consultancy company's Easy Access user list.
When you sign in on QuadriDCM Easy Access, you will see projects from multiple QuadriDCM servers, as long as your Vianova ID has been granted access to these different projects. Which Vianova ID that has access to which projects, is controlled by the administrator of each company in their Easy Access configuration.
If you use the Novapoint GO app, your Vianova ID will also be your user identification there.
Vianova ID is not used as a user identification towards a QuadriDCM model. That user identification is inside the Quadri Model Manager.