static void Main(string[] args)
        {
            Path3D myPath3D = new Path3D(new Point3D(-5, 55, 444), new Point3D(44, -5, 77), new Point3D(10, 20, 30), new Point3D(47, 74, -4));

            myPath3D.AddPoint(new Point3D(21, 45, -4));
            myPath3D.AddPoint(new Point3D(-5, -7, -55));
            myPath3D.AddPoint(new Point3D(45, 54, 77));

            Storage.SavePath(myPath3D);

            Path3D newPath3D = Storage.LoadPath3D("ExistPath.txt");
        }
        public static Path3D LoadPath3D(string fileName)
        {
            Path3D path = new Path3D();
            string fileNamePath = string.Format("{0}{1}", "../../", fileName);

            if (File.Exists(fileNamePath))
            {
                using (var reader = new StreamReader(fileNamePath))
                {
                    string line = reader.ReadLine();
                    while (line != null)
                    {
                        double[] coordinates =
                            line.Split(new char[] {'{', '}', ',', ' '}, StringSplitOptions.RemoveEmptyEntries)
                                .Select(double.Parse)
                                .ToArray();
                        path.AddPoint(new Point3D(coordinates[0], coordinates[1], coordinates[2]));
                        line = reader.ReadLine();
                    }
                }
            }
            else
            {
                Console.WriteLine("The source file not found.");
                path = null;
            }
            return path;
        }