First of all thank you for this awesome framework.
Just want to know whats the purpose of the terrain and why is that when I load my point cloud without a terrain, it floats above the map layer.
But after loading the
terrainProvider: Cesium.createWorldTerrain(), it sticks at the ground.
I think you answered your own question, no? Any model that are created using real-world coordinates would not fit on an earth represented by a simple ellipsis with a flat surface. The added terrain is based off real-world coordinates, and fits with your model well. Remove the terrain, and the model will float in the sky against a flat non-real-world surface.
Thank you so much for the clear explanation!
Recognize that the “quality” of the Cesium World Terrain differs from region to region and your point cloud may not conform well in certain areas.