Rotate axis

1. A concise explanation of the problem you're experiencing.
I need to get and axis to rotate the globe (camera) after the user manually rotated it for Camera.rotate() method. Also need a sign of the angle of rotation. Any idea? Please, point me.

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
var userAxis;
viewer.scene.camera.moveEnd.addEventListener(function(e) {
    // here?
    userAxis = getUserAxis();
});

function getUserAxis() {
    // ???
}

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

I need to continue to spin the globe after the user releases it.
screenSpaceCameraController.inertiaSpin = 0.999999 works like this, but I need constant speed.

I think what you might need to do is keep track of the camera’s last position and orientation, and then let it keep going in this direction vector. This is what the ScreenSpaceCameraController does, you can see how that works for reference here:

https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/ScreenSpaceCameraController.js#L332-L342