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[General] Question about VTK Format, Time and ParaView

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Old   April 5, 2013, 06:20
Default Question about VTK Format, Time and ParaView
  #1
ngj
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Niels Gjoel Jacobsen
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Dear all,

I am working on a small conversion tool for a specific mesh type in OF into VTK format (UNSTRUCTURED_GRID). The file names are given a name and a incrementing index, though, I would also like to be able to put a string with the actual time in animations, etc.

Therefore, I have added this part into the VTK file:

Code:
FIELD FieldData 1
TIME 1 1 double
204.0048
and this makes it possible for me to see this variable in the Information tab in ParaView.

My question is how I can get this data in a string in paraview, i.e. similar to the Annotate Time filter, though, this does not work on my case. I have uploaded a small VTK sample for your convenience here:

http://www.student.dtu.dk/~ngja/vtkSample.tar.gz

Thank you for your attention,

Niels
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Old   April 7, 2013, 12:55
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Bruno Santos
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Hi Niels,

I gave it a few shots in ParaView and Googled around to check on this topic... and I think I've seen where you've gotten this idea: http://www.visitusers.org/index.php?...e_in_VTK_files

Problem is that this specific time information is something that VisIt implemented:
Quote:
Since VTK files do not have a specific construct for doing so, VisIt implements a convention where CYCLE and TIME values can be added as FieldData in the file.
If you do switch to VisIt, I think you should move the time information closer to the beginning of the file:
Code:
# vtk DataFile Version 2.0
faMesh
ASCII
DATASET UNSTRUCTURED_GRID
FIELD FieldData 1
TIME 1 1 double
204.0028
POINTS 1763 float
Because the wiki page clearly states that:
Quote:
Pay attention that the field data comes right after the DATASET type in the VTK file.
If you do want time associated with your VTK files, you'll have to use the XML version of VTK files, as presented here: http://paraview.org/Wiki/images/2/20...n-ParaView.ppt

Best regards,
Bruno
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Old   April 7, 2013, 17:22
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Niels Gjoel Jacobsen
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Hi Bruno,

Thank you very much. This have given me some directions to work with. Most appreciated.

Kind regards,

Niels
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Old   December 17, 2013, 10:05
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Good afternoon,

I wanted to follow up on this. I finally had the time to re-visit the time stamp for VTK files in ParaView, and the hint by Bruno worked beautifully. Now, I merely have to clean up my code (a lot).

Thanks again,

Niels
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Old   July 12, 2014, 19:07
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Hello,
I am very interesting by using the time in a VTK file but I don't succeed to do that yet.

Is-it possible to give me a sample ?

Thank you in advance.
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Old   July 13, 2014, 07:32
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Good morning,

Yes, please find an example attached to this post. All you need to do is to open the file collection.pvd in paraFoam/paraView and you are set. You see a deforming sand bed and the VTK-format is for the faMesh of my computational domain. Now you will be able to insert the "Time Annotation", and it will change the time, when you go through the indices.

The writer itself, however, utilises some code, which we have decided to keep in-house for the moment, so I can unfortunately not share the code itself.

One thing, which I was unsuccessful in doing, was to write in binary format, so if you get around to understand the formatting of the *vtp files in binary, please share your knowledge.

Kind regards,

Niels
Attached Files
File Type: gz faMeshVTK.tar.gz (39.0 KB, 104 views)
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Old   July 13, 2014, 14:02
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Ok Thank you, don't worry I have yet done the Writer is yet done. I wanted to improve it and thank to you I will succeed.

For the binary file I don't use it because I have to read data in the text file if I want. good lucke
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Old   November 16, 2016, 11:38
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Hi Niels,
Thanks to your example I have written a program to get my data in VTK XML format (StructuredGrid) in order to use ParaView as visualization tool.
If my complete flow domain is hexahedral (for example, 4 blocks) it works well.
But if my complete flow has an L shape, for example, it doesn't work. ParaView asks more data.
Do you know the reason ?
Best regards,
Stephane.
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Old   August 9, 2022, 10:29
Question time in binary vtk file
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Has anybody managed to add time to a binary vtk file yet?

Adding the above mentioned entries to the header works for ascii but paraview crashes when using binary:


Code:
# vtk DataFile Version 2.0
sampleSurface
BINARY
DATASET POLYDATA
FIELD FieldData 1
TIME 1 1 double
204.0028
POINTS 4693 float
<#
;;r<#
;V;C<#
I have large numbers of OpenFOAM postProcessing surfaces with varying time steps that I want to look at. Very frustrating.


Thanks!
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