[Paraview] Selection of points

[Berk Geveci]

This is a good solution but it won't work if you save the state and
restore it. What Eric refers to in his response about global ids
should work as well but also support saving state. This same issue
came up related to information visualization where the selection is a
set of nodes from a graph. The decision made there was to add support
for saving out the selection and loading it back.

-berk


On Mon, Aug 4, 2008 at 11:01 AM, John Biddiscombe <biddisco at cscs.ch> wrote:
> Eric
>
> No. My particles already have a global Id which I use to track them
> independently. The trouble is (was), that when you select some in ParaView,
> it uses their Id taken from the index they have in the vtkPoints list (or
> Cell Id if using verts) and noy my "ParticleId" array. This order can change
> arbitrarily in my data. As time steps change - the selected points
> constantly shift about.
>
> I fixed the problem by creating a vtkSnapshot filter which simply captures a
> dataset when you create it. It caches the result and never updates anything
> from then on. This way I can select a bunch of particles using the mouse,
> copy the active selection, then snapshot it. I then pass this into the
> TTemporalTrails filter as the selction input (you might need to update your
> copy to get this filter). I can now pick individual (or groups) of particles
> at time T=large, capture them, go back to T=0 and draw pathlines only for
> thos eI wanted. Nice. This is also handy because particles can be injected
> at differnt times and if their Id doesn't exist at some T value, the trails
> filter just skips them. The ones selected get drawn - if they exist.
>
> JB
>
>> Hey John,
>>
>> I'm trying to make sure I understand your question -- would your problem
>> be solved if your particles had a Global ID associated with them, which was
>> a unique "tag" that didn't change over time? (Then, the selection type could
>> be "global id" and shouldn't reorder when time is stepped back to zero.)
>>
>> I've had to add a Global ID assignment to my version of the Xdmf reader so
>> that my animated particle data could be selected and have attributes plotted
>> over time, etc.
>>
>> Talk to you later,
>> -Eric
>>
>> ------------------------------------------------------
>> Eric E Monson
>> Duke Visualization Technology Group
>>
>>
>>
>> On Jul 22, 2008, at 3:46 AM, John Biddiscombe wrote:
>>
>>> I have a dataset which consists of animating particles. I can select a
>>> region of space and get the Id's of certain particles. I now wish to pass
>>> this list back into my Pathline filter so that only the particles selected
>>> are drawn with pathlines. However, when I hit the back button for the
>>> animation to return to time zero, the selected particles now change. I can
>>> change the selection type to Id - which is great because I can use this
>>> information directly in the pathline filter to pick out the lines, but again
>>> - when I change time step, the particles are re-ordered and my information
>>> is lost.
>>>
>>> I'd like to copy the active selection - and then fix it - so it is now
>>> disconnected from the pipeline and becomes a static piece of data which does
>>> noit change with time.  If I save the selction to disk, I can load it and
>>> use it as I'd like to. Is there a way of copying the active selection - and
>>> disconnecting it from the pipeline so that I can skip the disk save/load
>>> stage and pass the selection directly to my pathline filter?
>>>
>>> thanks
>>>
>>> JB
>>>
>>> --
>>> John Biddiscombe,                            email:biddisco @ cscs.ch
>>> http://www.cscs.ch/about/BJohn.php
>>> CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
>>> Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82
>>>
>>>
>>> _______________________________________________
>>> ParaView mailing list
>>> ParaView at paraview.org
>>> http://www.paraview.org/mailman/listinfo/paraview
>>
>
>
> --
> John Biddiscombe,                            email:biddisco @ cscs.ch
> http://www.cscs.ch/about/BJohn.php
> CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
> Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82
>
>
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