[vtkusers] : Integration, Streamline and RectilinearGrid

[Christian Poecher]

Dear group,

I have a problem with a computational fluid dynamics visualization.
I am working on a vtkRectilinearGrid(RectGrid) of vectors and use
streamlines to visualize the flow of particles over time. There is a
detail, which are important for my work, which I do not understand.
When calculating the streamline, vtk starts using lots of CPU and
allocates more and more memory, if I let the streamline start at some
specific points of my RectGrid. After a while vtk terminates with an
error message. It happens both if I use vtkRungeKutta2 or
vtkRungeKutta4, but if I change the integrator vtk crashes at different
points of the RectGrid. That is why I believe that the problem occurs
when integrating. Maybe the truncation condition specified by the method
SetMaximumPropagationTime of vtkStreamLine does not work as it should.
Maybe the numerical integration does not converge. If I use a very small
value for SetIntegrationStepLength (0.00001), vtk does not crash in
those critical points, but throws an error message: "vtkPolyLine
(0x014803C0): Coincident points in polyline...can't compute normals". 
Any ideas/suggestions/experience with such a problem?

Chris



-- 
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Christian Poecher                      mailto:poecher at icom-consulting.de
ICOM GmbH   					Phone: +49 241 9367-1554
Schloss-Rahe-Str. 15, 52072 Aachen, Germany     Fax  : +49 241 9367-1589
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