Determine if geographic coordinates are visible

Hi everyone,

My project needs to determine if given degree coordinates (on the globe surface) are visible by the camera. The following code has been written for that purpose:

const viewer = new Cesium.Viewer("cesiumContainer"); // for instance
// set the camera over the pacific ocean = new Cesium.Cartesian3(-33517534.12007907, -10816522.975550467, 2121682.0018882686); = new Cesium.Cartesian3(0.949949844026326, 0.30656056846902546, -0.06013245125809427);

let ellipsoid = viewer.scene.globe.ellipsoid;
let cameraPosition =;

let bs = Cesium.BoundingSphere.fromEllipsoid(ellipsoid);
let occluder = new Cesium.Occluder(bs, cameraPosition);

let point = Cesium.Cartesian3.fromDegrees(180, 0, 0.001);
let isPointVisible = occluder.isPointVisible(point);


For these coordinates (180, 0, 0.001), true is returned in the Cesium SandCastle, which seems OK.
However, I cannot manage to get this working for latitudes different from 0. For example, (180, -1, 0.001) returns false.

I guess the problem here is the altitude, so I have tried to get the right altitude by casting a Ray by following the instructions on this topic.
However I could not manage to make this work either.

I do not know much about Cesium yet, and maybe I am missing something trivial here. Would anyone be willing to point me any mistake I could have made, please?

Thank you all!

Cesium version: 1.94.3


I am dealing with a similar issue with isPointVisible and was wondering if you were able to solve your issue?