Hi all, On vtkIVWriter line 137 there is: colors->Delete(); But it is ouside of the 'if(colors)' condition. What did I misunderstood ? Thanks mathieu -- Mathieu Malaterre CREATIS 28 Avenue du Doyen LEPINE B.P. Lyon-Montchat 69394 Lyon Cedex 03 http://www.creatis.insa-lyon.fr/~malaterre/