What would the game be like? There are many ways to get as-built buildings at scale from existing datasets. For example there are cesium tiles. OSM data contain

What would the game be like? There are many ways to get as-built buildings at scale from existing datasets. For example there are cesium tiles. OSM data contains footprint polygons with height which means extrusion is trivial. To explore know production algorithms for pointcloud-to-mesh check out the ones provided in cloudcompare and meshlab and see if any fit your purpose. Afaik there is no one objectively best recipe so you need to know what you want and be aware of the tradeoffs and constraints. Note that for real time large scale cityscapes for complex buildings you likely need lods, impostors etc - which you don’t get for free. If you use just polygon extrusions you can likely bucket like a square kilometer of buildings to a drawcall (or more).