Thank you, that it!
Polyline goes under the terrain.
My application is for closed order, so I can't show full source of it.
But I made component for loading DEM tiles which are provided by Japanese
Geospatial Information Authority as TerrainProvider.
So, I will open this component as open source later.
Thanks for the info. If any parts of the app are publicly available (even if closed source), we would be happy to showcase it on the Cesium website like we’ve done for similar apps for Australia and France:
Thank you for helping me about this topic.
With your help, I have already publish Tile/TerrainProvider from Japanese Geospatial Information Authority’s API,
in Github.