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Bastil<br>
<br>
I cannot comment on the surface streamlines directly, as I'm not
familiar with the class that is used...but if it internally makes use
of the vtkStreamTracer filter code, then I can make the following
observation.<br>
<br>
The vtkStreamTracer class uses vtkDataSet FindCell to locate the start
point of a given streamline. It then builds links (vtkUnstructuredGrid
only) between cells so that as a streamline passes out of one cell and
onto the next, the neighbour can be located quickly. The findCell is
very slow as for an unstructuredgrid, it is a brute force search of all
cells. The build links is also very slow and if your grid is a single
20million cell dataset, it will take ages.<br>
<br>
About a year ago, I posted a request to this list for volunteers, to
test some improvements that I'd made to the StreamTracer code to <br>
a) make use of a cell locator instead of FindCell/BuildLinks to
accelerate the streamline searches.<br>
b) Clean up some caching to prevent certain operations taking place on
every iteration of the inner integration loop within the streamline
calculation.<br>
<br>
<u><b>I got no volunteers, so I never committed my code</b></u>. Since
then I had problems with maintenance of my tree and reverted all my
changes (I was only interested in my TemporalStreamTracer code anyway),
but a few weeks ago, I decided to re-tweak the streamline filter to see
if my new CachingInterpolatedVelocityField would work with it. I found
that my own streamline generation was greatly improved (20million cells
approx in my case also).<br>
<br>
The changes are in the pv-meshless tree (use google), but I will not
offer further assistance as I'm very busy this week. So if you want to
try it out, you are welcome - and if you can post results to this list,
then so much the better - and it may prompt me into a second round of
fixes. (the changes I made a few weeks ago were not thorough and I need
to spend a little more time on it before it's ready to be committed).<br>
<br>
JB<br>
<blockquote cite="mid:49C3F5BA.9020008@yahoo.de" type="cite">
<pre wrap="">Hi group,
I tried creating some surface streamlines as described in the wiki.
Process seemed to work but was extremly slow for me so I could not wait it.
I have large CFD models imported as ensight (~ 20 Million cells).
Paraview run for about five hours without an result for surface
streamlines from 50 seed points. I don't really know if this is normal?
Regards BastiL
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<br>
<pre class="moz-signature" cols="78">--
John Biddiscombe, email:biddisco @ cscs.ch
<a class="moz-txt-link-freetext" href="http://www.cscs.ch/">http://www.cscs.ch/</a>
CSCS, Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.07
Via Cantonale, 6928 Manno, Switzerland | Fax: +41 (91) 610.82.82</pre>
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