Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
float length = ray.origin.y / (Mathf.Cos(Mathf.Deg2Rad * Vector3.Angle(Vector3.down, ray.direction)));
Cube.transform.position = ray.GetPoint(length);
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
float length = ray.origin.y / (Mathf.Cos(Mathf.Deg2Rad * Vector3.Angle(Vector3.down, ray.direction)));
Cube.transform.position = ray.GetPoint(length);