pick and raySphere get different result

var ellipsoid = viewer.scene.globe.ellipsoid
      let cartesian = viewer.scene.pickPosition(movement.position)
      if (cartesian) {
        let cameraPosition = cesiumManager.cesiumViewer.camera.position
        let horixontalRay = cesiumManager.cesiumViewer.camera.getPickRay(movement.position)
        // let horizontalDirect = horixontalRay.direction
        // let verticaleRay = new Cesium.Ray(cameraPosition, horizontalDirect)
        let verticalPointPosition = Cesium.IntersectionTests.raySphere(horixontalRay, this.displayGs3DTilesetList[this.curDisplayGs3DTileset].boundingSphere)
        let getpoint = Cesium.Ray.getPoint(horixontalRay, verticalPointPosition.start)
    Why getpoint is different from cartesian ?

I think that’s because [pickPosition](https://cesiumjs.org/Cesium/Build/Documentation/Scene.html?classFilter=Scene#pickPosition) reconstructs a 3D position from the depth buffer, whereas raySphere and getPoint actually compute the intersection in 3D space.

How different are the results you’re getting?

When the cartesian is
the getpoint is

I think one difference might be that for getPoint you’re computing against a boundingSphere, whereas the ellipsoid itself is not a sphere. Another issue could be is that the pick function isn’t executed synchronously with the render loop. Running this code in a postRender event will fix that if that’s the issue.

If you can put together a running Sandcastle example of this I can try to take a closer look at this discrepancy. In the mean time, you can take a look at the source yourself to get a better idea of exactly what each function is doing. Here’s pickPosition to get you started. It also might be related to this issue: