What this is
Public 3D terrain for the continental United States, built from USGS 3DEP elevation data: a 10 m base everywhere, with 1 m lidar detail (USGS “S1M”) wherever USGS has released it. Heights are NAVD88 + GEOID18 (NAD83(2011) ellipsoid heights).
v1 is live today. v2 rebuilds all of it with a new mesher — closer to the source data and seamless between tiles — and adds every S1M area USGS has published. Until an area is live in v2, v1 keeps serving it.