// add more CP's, rotating path by random angles
        void addTrackCP()
        {
            float   rndX = Random.value * CurvationX * DTUtility.RandomSign();
            float   rndY = Random.value * CurvationY * DTUtility.RandomSign();
            Vector3 p    = TrackSpline.ControlPoints[TrackSpline.ControlPointCount - 1].localPosition;

            mDir = Quaternion.Euler(rndX, rndY, 0) * mDir;
            TrackSpline.InsertAfter(null).localPosition = p + mDir * CPStepSize;
        }