OSM Buildings not showing on custom DTM


My goal is to load custom terrain and have buildings on top. I am following this tutorial: https://cesium.com/learn/3d-tiling/ion-tile-terrain/.

When looking at the result in Stories, the terrain looks fine but there is no building on top of the custom DTM I uploaded. In the picture below, the bottom part is where my custom DTM is, top part is Cesium World Terrain. We can see some buildings missing near the lake.

  • On the rest of the map, buildings ok displaying properly
  • I can’t see the buildings even when hiding the Bing Maps Aerial layer either
  • I tried deleting the Cesium OSM Buildings layer and adding it again but it is the same.

What could be causing this ?

So there are also some floating building where the custom DTM is:

My guess is that since my DTM has different altitudes than the Cesium World Terrain, the buildings are not displayed at the right height… Is there a quick fix for this or should I find another buildings layer that fits my data ?