public override void OnInspectorGUI()
    {
        DrawDefaultInspector();

        Track myTrack = (Track)target;

        if (GUILayout.Button("AddBifurcation"))
        {
            myTrack.AddBifurcation();
        }
        if (GUILayout.Button("AddCurve"))
        {
            myTrack.AddCurve();
        }
        if (GUILayout.Button("Export"))
        {
            // Export.obj mesh
            myTrack.InstantCombineMeshes();

            //if (EditorApplication.isPlaying)
            myTrack.GetComponent <MeshExporter>().Export();

            myTrack.GetComponent <MeshRenderer>().enabled = false;
        }
    }