[Paraview] threshold filter problem

[Dominik Szczerba]

Hi,
I have a tetmesh with a scalar field at the cell centers. I want to
extract tets with a scalar value within a certain range. It only works
after cellData2nodeData, which, however, changes the values due to
interpolation (actually, destroys them for me). 1) is there a particular
reason threshold filter is not available for cell centered data? 2) how
to walk around this problem?
Thanks for any hints
Dominik
-- 
Dominik Szczerba, Dr.
Computer Vision Lab CH-8092 Zurich
http://www.vision.ee.ethz.ch/~domi