Why use ellipsoids instead of regular spheres in Cesium？As is well known, using an ellipsoid results in greater computational complexity. Would using a regular sphere like Mapbox be a better solution？
Hi @xingrui94 - perhaps it’s about the birth of Cesium - it seems like it was a project for NASA - as you know, it’s closer to technology and science than to games and arts. Here I’ll recall a bit from my education - our planet is not very smooth - it’s more like a crooked apple - its radius is not constant and can differ by hundreds of kilometers - thus, an ellipsoid would be more suitable than simple figures - the next stage - apply deformations for a very general approximation over thousands of kilometers - did you know that there is a trench more than 10 kilometers deep in the Indian Ocean and conversely in the North Atlantic, there’s a hill slightly higher (not in ground - sea level)? Our poles are also depressed like on an apple by several kilometers. Thus, it already starts to differ significantly from a sphere - and if you will need image more realistic then in a game or a movie - but as sample for applications like displaying trajectories of spacecraft, air, drones, seaships, trains - may be you can agree that an error even by 1 kilometer above or below the earth is critical. What to say when the difference can be tens or hundreds of kilometers? I think it would be great to build a sphere of the average radius of the planet (6400 km) and compare intersections with the spheroid. I hope I managed to explain that it’s not just developers’ games out of boredom.
Nice sample image, you can see here:
And here:
Have a nice day.