The modelling and simulation layer comprises digital models detailing assets’ physical and functional traits across various scales. These models facilitate decision support tools for applications such as urban planning, drawing from local (e.g., building management systems) and urban (e.g., geographic information systems) levels.

Different digital representations and simulations serve varied purposes, from real-time control to city planning. Predefined data schemas and organized modelling processes are essential for aligning digital twins with target applications, whether at the building or city level. Additionally, the modelling & simulation Layer aids the management and integration layer by facilitating model-driven interoperability, ensuring seamless information exchange among heterogeneous digital twins without compromising their curation.