[Paraview] Stream Function question...

[Renato N. Elias]

Hello all,

I was wondering if anybody could give me a hand about the following
question:

I'd like to cut a 3D CFD model (unstructured mesh) by a plane and compute
the scalar stream function using this 2D plane. Furthermore, this stream
function as a scalar parameter could be used to produce countour lines in
the 2D plane. Note that this countour line would be equal the stream lines
over the 2D plane.  

When working with Ensight there is a function provided by the CFD calculator
only to compute stream functions, vorticity, swirl, etc... But I'd rather
use only Paraview in my visualizations. Ensight is too boring to use... 

I've already tried something with the Paraview's calculator but I don't know
how I could compute derivative greatness with this calculator. 

Thanks in advance for any help

Renato N. Elias
Rio de Janeiro/Brasil