User experience

Today, digital models of buildings are becoming widespread and are widely offered or even mandatory for tertiary or public buildings.[1] Currently, the models are used mainly during the design and much more rarely up till the delivery of the building. The future need and the challenge are to make this digital model usable throughout the life of the building, whether it is a living, dynamic digital twin, enabling building managers and users to interact through it.
How can this be achieved? How should this digital twin be made? What are the theoretical and technological challenges? But first, what are the basic elements for understanding this problem and what is the state of the art?