Digital Twin (DT) technology is increasingly recognized as a key enabler for optimizing design, operation, and management across the built environment. While several reviews have addressed DTs in either building- or city-scale contexts, a comprehensive integration of these two perspectives remains limited. This paper provides an updated overview of DT developments from Building Digital Twins (BDTs) to Urban Digital Twins (UDTs), aiming to identify convergences, divergences, and future directions. The analysis is conducted through a review of recent literature and selected case studies, considering technical, environmental, economic, and social dimensions. Findings reveal that although BDTs and UDTs share common conceptual and technological foundations, scaling from single assets to complex urban systems introduces new challenges in terms of interoperability, governance, and data management. Furthermore, while environmental and economic benefits are relatively well-documented, social implications, such as citizen engagement, inclusivity, and behavioral modeling, remain underexplored. This review highlights the novelty of adopting a cross-scale perspective, emphasizing the importance of integrating technical and social aspects to fully exploit the potential of DTs for sustainable and resilient transitions. The study concludes by outlining research gaps and recommending strategies for developing more integrated, socially aware DT frameworks in both building and urban contexts.
Iossa et al. (2025) studied this question.