Hi, look at: http://public.kitware.com/pipermail/vtkusers/2004-March/023276.html also the line "I know this doesn't find your bug in the program..." ;) greets Ingo --- Dr.-Ing. Ingo H. de Boer Polytec GmbH Polytec-Platz 1-7, 76337 Waldbronn, Germany phone: ++49 7243 604 106 fax : ++49 7243 604 255