Unity OnBecameInvisible() fires though object is still visible

Question

I have a Mesh Renderer and a script assigned to a rotating sphere with a hole in it. The sphere has no specific or special place in hierarchy, its just next to the camera. The script part looks like this:

void OnBecameInvisible() {
  Destroy(gameObject); 
}

Problem is, that when I pass the sphere with my ball, even though the sphere is still half visible, it gets deleted. I have no other camera in the scene, and the one Im using is marked as the main camera.

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Video

Answer 1

Instead of using OnBecameInvisible for culling objects you've passed, just check if it's sufficiently behind the camera in Update:

Camera mainCam;
[SerializeField] float maxBehindDistance = 0.5f;

void Awake() { mainCam = Camera.main; }

void Update()
{
    Vector3 relPos = mainCam.transform.InverseTransformPoint(transform.position);
    if (relPos.z < -maxBehindDistance)
    {
        Destroy(gameObject);
    }
}