A digital twin is a digital representation of a project (process, system, object, etc.) directly from the 3D design model and can be quite static in its natural state.
A virtual twin goes deeper, introducing data beyond shapes, sizes, and dimensions. Temporal data about how a space or thing behaves over time reveals how it’s being used. Meanwhile, connecting the model to data from the wider environment lets you situate it in a more realistic modeling framework to reveal even richer performance measurements.