[aspect-devel] Evenly spaced vectors, dynamic pressure

[Jonathan Perry-Houts]

After this thread I tried tracking down wtf was up with the uniform 
glyph distribution. Turns out it's a paraview bug. I fixed it, and I 
guess the patch will be part of the next release. 
https://gitlab.kitware.com/paraview/paraview/merge_requests/2733

However, the fix still relies on there being a node somewhere near each 
glyph, which means that for adaptively refined meshes some glyphs appear 
and reappear during the course of the model. If you want them to stay 
put, you still have to interpolate your model onto a uniform mesh.

-JPH

On 09/06/2018 07:30 PM, Adam Holt wrote:
> Thanks Jonathan!  After upgrading to the newer Paraview (5.5), the filter works nicely. Again, it didn't do the time-stepping for version 5.2, so I guess the issue is with the older version. Good to know.
> 
> And totally agree about the "uniform spatial distribution" - It took me a while to figure out why this was not showing glyphs for my 2-D models...
> 
> many thanks,
> Adam
> 
> ________________________________________
> From: Aspect-devel [aspect-devel-bounces at geodynamics.org] on behalf of Jonathan Perry-Houts [jperryh2 at uoregon.edu]
> Sent: Thursday, September 06, 2018 7:41 PM
> To: aspect-devel at geodynamics.org
> Subject: [aspect-devel]  Evenly spaced vectors, dynamic pressure
> 
> On 09/06/18 12:25, Adam Holt wrote:
>> Hi all!
>>
>> I am a relatively new user of ASPECT, and have ran into some tricky things related to visualizing/post-processing ASPECT output using Paraview. I wondered if anyone had experience with the following:
>>
>> First, plotting evenly spaced velocity vectors for models with mesh refinement. As the element sizes vary dramatically, plotting vectors using "Every Nth Point" (Paraview Glyph option) produces very uneven vector coverage. I thought I had solved this by interpolating the data onto a plane (using Paraview function "Resample with dataset"), but the result of this function (an evenly spaced velocity field) does not time evolve with the simulation (at least for Paraview 5.2.0). Has anybody ran into a similar issue?
> 
> That seems to work in Paraview 5.5.0 (it does evolve with the simulation
> for me). Not sure if it matters, but I used a "Plane" source as the
> uniform grid to Resample on. I attached a custom filter that works for
> me (import it with Tools>Manage Custom Filters>Import).
> 
> It's ridiculous that the glyph filter's "uniform spatial distribution"
> option doesn't do this automatically. That's exactly what I would expect
> it to do. Apparently it just selects uniformly spaced points, and if
> there happens to be a node there, it will plot a vector, otherwise it
> skips it. That's why it almost never works for "small" data sets like a
> 2d mesh.
> 
>> Second, I am interested in the dynamic pressure field and wondered how best to retrieve it from my (incompressible) models. For such models, I assume it can be computed by subtracting the horizontally-constant static pressure from the pressure outputted (the 'nonadiabatic pressure' output variable). Is this something that should be done in Paraview, or by writing a new post-processor plugin?>
>> Thanks in advance for any input!
>> Adam Holt
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>>
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-- 
Jonathan Perry-Houts
Ph.D. Candidate
Department of Earth Sciences
1272 University of Oregon
Eugene, OR 97403-1272