[vtkusers] isosurface plane through an vtkUnstructuredGrid

[tom fogal]

 <006501c482bf$9f3fcee0$0200a8c0 at PAUL>"Arne Mittelstaedt" writes:
>I want to realize an isoSurface-plane through a vtkUnstructuredGrid with
>FlowData (points in space, vectors for direction and scalar-Values for
>velocity). Have anyone an example for that? I will describe it more

I believe the object you are looking for is vtkContourFilter.
Contour-something at least. I'm not quite sure how it works yet, thats
actually one of my projects for the week =)

>Another way I was thinking over are Streamlines, but I have never found an
>Example for Streamlines that can take Data from an unstructuredGrid.

vtkStreamTracer takes input from any vtkDataSet*. I have successfully
plotted streamlines from both a Rectilinear and Unstructured grid.
Something like:

StreamTracer->SetInput(some_grid);
StreamTracer->SetStartPosition(3-component float array);
StreamTracer->SetMaximumPropagationUnitToLenghUnit();
StreamTracer->SetMaximumPropagation(9E8);
StreamTracer->SetIntegrationDirectionToBoth();

and then attach its output to a vtkTubeFilter, which outputs to a
PolyDataMapper, to an Actor, which gets attached to a renderer... you
probably know that routine.
One 'gotcha' for me was setting the maximum propagation. Before I did
that my streamline was nothing but a tiny dot.

>How can I realize such plane/streamline? Does I have to convert the
>UnstructuredGridData into another Dataset?

Sorry I can't help you with the plane, but the above should work for
the streamline...

>Thank you very much in advance

You are very welcome.

-tom