Berk, That might be the correct interpretation for the first video, which I think uses a steady (i.e. not time-dependent) flow field. For steady flows, streamlines, streaklines, and trajectories are all identical. But if you look at the second video, I think you can see that they are plotting Lagrangian trajectories. My velocity data is time-dependent, so I think I need the trajectories. -Ryan
On Tue, Jan 14, 2014 at 2:47 PM, Berk Geveci <berk.gev...@kitware.com>wrote: > Hi Ryan, > > When I look at these movies carefully, it looks like they are using > streaklines that are seeded for a short burst. It looks like they pick > a number of seeds each time step and start a streakline from each and > keep them active for a few time steps. Then those streaklines seem to > be killed eventually. It also appears as if they are playing with > transparency depending on the age of the streakline. Am I right? > > -berk > > On Tue, Jan 14, 2014 at 2:20 PM, Ryan Abernathey > <ryan.abernat...@gmail.com> wrote: > > Hello, > > > > I am continuing my ongoing quest to do something like this > > > http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=267.73,5.54,350 > > or this > > http://www.youtube.com/watch?v=xusdWPuWAoU > > in Paraview using ***time dependent velocity vectors***. > > > > While the LIC plugin is very cool, it does something different. I > followed > > the previous suggestion and tried to use the streamline filter: > > http://paraview.org/Wiki/ParaView/Custom_Filters > > Unfortunately that is not quite right either. > > > > The problem with the streamline filter is that it treats each timestep as > > completely independent and regenerates the streamlines whenever the > velocity > > field changes. (This is the correct behavior: streamlines are defined by > the > > *instantaneous* flow.) > > > > What we see in those videos are truly particle trajectories. In > particular: > > - particles are seeded randomly (in space and time) > > - they leave a decaying trail (sometimes called a streaklet) > > - the particles disappear after a short lifetime > > This is the combination of ingredients I need to reproduce in paraview. > > > > The best candidate is clearly the ParticleTracer filter. However, I have > hit > > a serious problem: it doesn't appear that this filter is able to make the > > particles "die" after a temporal lifetime. Compare the v 3.3 > documentation > > http://paraview.org/OnlineHelpCurrent/ParticleTracer.html > > with the current documentation > > > http://paraview.org/Wiki/ParaView/Users_Guide/List_of_filters#ParticleTracer > > In the old version, there was an option called "Termination Time" that is > > missing from the new version. > > > > Without such an option, the particles will never disappear, the domain > will > > get more and more crowded, and the computational expense will grow with > > time. > > > > Let me know if you have any suggestions or if you know how to re-enable > this > > Termination Time option. > > > > Thanks a lot, > > Ryan > > > > _______________________________________________ > > Powered by www.kitware.com > > > > Visit other Kitware open-source projects at > > http://www.kitware.com/opensource/opensource.html > > > > Please keep messages on-topic and check the ParaView Wiki at: > > http://paraview.org/Wiki/ParaView > > > > Follow this link to subscribe/unsubscribe: > > http://www.paraview.org/mailman/listinfo/paraview > > >
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