[Paraview] multiple time steps and particle tracing

Fri Aug 21 12:56:37 EDT 2009

That's the basic idea.  It takes as input a group of particles and, as it gets executed for new time steps through an animation, builds a trail behind them.  The output of the particle tracer makes for good input to the particle pathlines filter.

Output-0 is the pathlines themselves.  Output-1 is the particles used for the paths.  It is a bit like a pass-through of the input, except that if the filter masks any points it will also mask them on this output.  In the next release of ParaView, these outputs will have names that actually represent what geometry is output on each port.

-Ken

On 8/21/09 10:38 AM, "Adam Wiktor" <awiktor at emory.edu> wrote:

Thanks Ken, that got everything working. One more question, though. I'm wondering what the Particle pathlines filter does. I saw in a tutorial that it connects to the particle tracer. Does it create path lines similar to streamtracer? What do the various properties do? And what are output-0 and output-1?

Thank you very much for all your help!

- Adam

On Fri, Aug 21, 2009 at 11:18 AM, Moreland, Kenneth <kmorel at sandia.gov> wrote:
You could ignore it.  You get a bunch of warnings, but it still looks like the data is being generated correctly.

-Ken

On 8/21/09 8:27 AM, "Adam Wiktor" <awiktor at emory.edu <http://awiktor@emory.edu> > wrote:

Hi Ken,

Thanks for figuring that out. Can you think of any way around this bug? The only reason I needed the temporal shift scale filter was so that the particle tracer knew the spacing between time steps (by default it's 1 sec, but it should be 0.0275 sec).

Thanks again,

Adam

On Tue, Aug 18, 2009 at 5:41 PM, Moreland, Kenneth <kmorel at sandia.gov <http://kmorel@sandia.gov> > wrote:
I can see the problem with the data set you sent.  I posted a bug report for it:

http://www.paraview.org/Bug/view.php?id=9435

I'm pretty sure that this bug is caused by a non-feature of ParaView that causes the data type of the input of a temporal shift scale (and some other temporal filters) to spontaneously convert to temporal data.  John B. is supposed to be working on that.  I have no idea what the eta is.

I still think the particle tracer does about what you are looking for.  I'm not really the right person to give advice here as I have limited experience with the filter (again John B is the expert), but if you only want to inject points at the first time step, you should be able to do that by setting the "Force Reinjection Every NSteps" parameter to something very large.

-Ken

On 8/11/09 2:36 PM, "Adam Wiktor" <awiktor at emory.edu <http://awiktor@emory.edu>  <http://awiktor@emory.edu> > wrote:

Hi John and Ken,

Paraview seems to read the data fine. If I just load the data and don't apply the temporal shift scale, I don't get any error messages as I go through the frames. As soon as I apply the temporal shift scale and try to change time points, though, I get the error.

I've attached three time points out of the twenty that I'm using (the number in the file name is the time in ms). I checked, and paraview still gives me the error when only using these three. What I do is open the "Velocity-..vti" in paraview. I then click apply, and everything is still fine. When I apply the temporal shift scale filter, I don't get a message right away, but as soon as I go to the next frame (or any other frame) I get the error I mentioned. Do you know what could be wrong?

Also, I'm not completely sure that particletracer is what I'm looking for. What I need is something that's basically the same as the streamtracer, but that would incorporate the differences in the velocity in each of the time points. It would place a seed and integrate like the streamtracer up to the next time step, but then use the velocities in the next frame to continue the integration. Is that what the particle tracer does? And if so, what do I use as the input for port 1?

Thanks for the help,

Adam

On Tue, Aug 11, 2009 at 1:43 AM, John Biddiscombe <biddisco at cscs.ch <http://biddisco@cscs.ch>  <http://biddisco@cscs.ch> > wrote:
Adam

The first error is nothing to do with time, check how you are reading the data, something is not right. but I cannot diagnose it from here.

Also, back when I wasn't getting this error message, I tried applying the ParticleTracer filter, and got the following error message:

ERROR: In /home/awiktor/Desktop/ParaView3/VTK/Filtering/vtkDemandDrivenPipeline.cxx, line 728 vtkCompositeDataPipeline (0x11e2a10): Input port 1 of algorithm vtkTemporalStreamTracer(0x5be0420) has 0 connections but is not optional.
The ParticleTracer requires an input vector field and a seed point input. Same as for the Streamtracer, the first error you mentioned is probably causing one input to be null (port 0 = vector field, port 1 = seed points).

JB

   ****      Kenneth Moreland
    ***      Sandia National Laboratories
***********
*** *** ***  email: kmorel at sandia.gov <http://kmorel@sandia.gov>  <http://kmorel@sandia.gov>
**  ***  **  phone: (505) 844-8919
    ***      web:   http://www.cs.unm.edu/~kmorel <http://www.cs.unm.edu/%7Ekmorel>  <http://www.cs.unm.edu/%7Ekmorel>

   ****      Kenneth Moreland
    ***      Sandia National Laboratories
***********
*** *** ***  email: kmorel at sandia.gov <http://kmorel@sandia.gov>
**  ***  **  phone: (505) 844-8919
    ***      web:   http://www.cs.unm.edu/~kmorel <http://www.cs.unm.edu/%7Ekmorel>

   ****      Kenneth Moreland
    ***      Sandia National Laboratories
***********
*** *** ***  email: kmorel at sandia.gov
**  ***  **  phone: (505) 844-8919
    ***      web:   http://www.cs.unm.edu/~kmorel

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