With Cesium 1.3 , we need to provide a getTileDataAvailable function for the TerrainProvider.

in my function when the getTileDataAvailable returns false, no flat terrain is drawn.

Do we need to provide a default “flat” tile when getTileDataAvailable return false ?



When getTileDataAvailable returns false, the terrain for that tile is created by using the parent tile’s terrain for that area. If you return false for a root (level zero) tile, I believe you’ll see no terrain at all.

If you want something different than that, such as a smooth ellipsoid surface in the area of that tile, you’ll need to return true from getTileDataAvailable and return the geometry you want from requestTileGeometry. Take a look at EllipsoidTerrainProvider to see how to create a smooth ellipsoid surface tile.