diff --git a/tbox/viewer.py b/tbox/viewer.py
index ddabbc90fe01ec8dbc3c357e47f3d141c87dc3c1..c5f42697cfbbd50caac3dac6327197f64fb66acb 100644
--- a/tbox/viewer.py
+++ b/tbox/viewer.py
@@ -2,13 +2,13 @@
 # -*- coding: utf-8 -*-
 
 # Copyright 2020 University of Liège
-# 
+#
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
-# 
+#
 #     http://www.apache.org/licenses/LICENSE-2.0
-# 
+#
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -35,10 +35,13 @@ class GUI:
         if not os.path.isfile(optfile):
             self.defopt(optfile)
         cmd="gmsh %s %s %s" % (mshfile, posfile, optfile)
-        os.system(cmd)        
+        os.system(cmd)
 
     def defopt(self,fname='defaultflowOpt.opt'):
         f = open(fname,'w')
         f.write("General.Orthographic = 0;\n")
+        f.write('View[0].IntervalsType = 3;\n')
+        f.write('For i In {1:PostProcessing.NbViews-1}\n')
+        f.write('  View[i].Visible = 0;\n')
+        f.write('EndFor\n')
         f.close()
-