void ChangeMesh(int index)
 {
     // plane mesh
     if (index == 0)
     {
         myMesh1.gameObject.SetActive(true);
         if ((int)resolution.GetSliderValue() != myMesh1.N)
         {
             myMesh1.ResetMesh((int)resolution.GetSliderValue());
         }
         myCylinder.gameObject.SetActive(false);
         myMesh       = myMesh1;
         selectedObj  = null;
         selectedAxis = null;
         axisFrame.SetActive(false);
         MainCamera.transform.localPosition = new Vector3(0, 1.76f, -2);
     }
     // cylinder
     else
     {
         myMesh1.gameObject.SetActive(false);
         myCylinder.gameObject.SetActive(true);
         selectedObj  = null;
         selectedAxis = null;
         axisFrame.SetActive(false);
         MainCamera.transform.localPosition = new Vector3(0, 1.76f, -5.5f);
     }
 }