How to rebuild entire cities in 3D from photos?

Building 3D models of entire cities from photos for simulation requires handling massive complexity that breaks existing methods. City-Mesh3R divides cities into manageable chunks, reconstructs sparse maps via topological clustering and independent SfM per cluster, then densifies geometry with smart camera selection and curvature-aware remeshing before stitching pieces together. Result: watertight, simulation-ready meshes with fine detail at city scale.