Vector2 a = new Vector2(pathPoint.X, pathPoint.Y);

            Vector2 b = lastPoint;

            double deltax = b.X - a.X;
            double deltay = b.Y - a.Y;

            double angle_rad = Math.Atan2(deltay, deltax);
            double angle_deg = angle_rad * 180.0 / Math.PI;

            pathPoint.RotationZ = (float)angle_rad;