[Paraview] StreamTracer: Combined ReasonForTermination or select individual polylines?

[Liang Wang]

Thank you, Andy.


I):

I'm using 5.3 and your example is what I would get. But what I want is a
way to tell if the two streamlines from the same seed point are terminated
for different reasons. It might be more clear from the image I attached. I
would like to tell

1) closed field lines that have both ends terminated on the sphere surface
(the red tubes)
2) semi-open field lines that have on the ends terminated on the sphere
surface, the other goes out-of-domain (the red and blue tubes)
3) open field lines that have both ends out-of-bound (not shown in the
image, would be blue tubes)

(Or, ideal, I would be happier to be able to tell if the open end of the
semi-open field lines goes out of the southern or northern bound)

Indeed, I saw people doing this in Mayavi-based python (see
https://github.com/KristoforMaynard/Viscid/blob/dev/viscid/cython/streamline.pyx
and
http://kristoformaynard.github.io/Viscid/docs/master/examples/mayavi.html).
One obstacle I can see is that ParaView (or vtk?) probably treats the two
streamlines from the same seed point independently, thus it won't be easy
to tag them together.

II):

I realize that I am demanding too much. I tried your way of `Find Data`,
and now I am able to manually choose individual streamlines, which is
already helpful.



On Tue, Mar 14, 2017 at 3:17 PM, Andy Bauer <andy.bauer at kitware.com> wrote:

> Hi,
>
> What version of ParaView are you using?
>
> From my testing it looks like each direction for the stream tracer seeds
> has a separate reason for termination in PV 5.3 -- see the attached image.
> The domain is a box with length 20 on each side, the velocity is [1, 0, 0],
> the seeds are a line source going from min to max of the bounding box
> ([-10, -10, -10] to [10,10,10]).  The red is for when the maximum
> streamline length has exceeded my specified max length of 5 and the blue is
> for when the streamline exited the domain.
>
> Is there a case where the same reason for termination value is being used
> for multiple termination criteria?
>
> You can use the SeedIds cell data array in the Threshold filter or use the
> Edit->Find Data option to select a given streamline from the seed id.
>
> Cheers,
> Andy
>
>
>
> On Tue, Mar 14, 2017 at 2:24 PM, Liang Wang <frank0734 at gmail.com> wrote:
>
>> If the IntegrationDirection is set to BOTH, the two segments of the
>> streamlines from the seed might terminate for different reasons. For
>> example, one end might end due to STAGNATION, the other due
>> to OUT_OF_DOMAIN. When coloring by ReasonForTermination, then the two
>> segments are colored differently.
>>
>> My question is: Can a user create more cases of ReasonForTermination so
>> that we can tell examples like above? Or, how can I select individual
>> streamlines by its SeedIds (I tried IdsSelection, but that appears to work
>> for cell/point data only, not for polydata?)
>>
>> My current solution is to use threshold filter to select lines in the
>> different regions and apply different solid colors. But it would be nice if
>> I can handle a few different cases more directly, even if that involves
>> some coding in C++ or Python.
>>
>> Thanks.
>>
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