Clipping Issue with Ion Asset terrain provider

CesiumJS
1

Hi,

I’m not sure if clipping is the right concept but the issue I’m having is that the terrain seems no to clip properly against the polygons I put on top of it. Here is the sandcastle I’ve create to generate the following pictures: link.

image
image1260×623 89.6 KB

image
image1260×623 75.4 KB

and if I replace the terrainProvider by Cesium.Terrain.fromWorldTerrain I obtain the expected behavior:

image
image1260×623 87.9 KB

To create the Ion asset, I’ve uploaded a DEM TIF of the island

2

Finaly, I’ve figured out the solution

    const viewer = new Cesium.Viewer("cesiumContainer", {
    terrainProvider: new Cesium.Terrain( Cesium.CesiumTerrainProvider.fromIonAssetId(2495988)),
  });

rather then

    const viewer = new Cesium.Viewer("cesiumContainer", {
    terrainProvider: await Cesium.CesiumTerrainProvider.fromIonAssetId(2495988),
  });

I would be interested to better understand the difference between terrain and terrain provider?