[Paraview] Extract the dimensions (or extent) of a structured grid within a python script

[Guillaume Duclaux]

Thanks a lot Utkarsh for your assistance!

I've added the following to my python script, and it worked smoothly:

    inputPvts.UpdatePipeline()
    extent = inputPvts.GetDataInformation().GetExtent()
    print extent

returns:

(0, 512, 0, 128, 0, 512)

Cheers

Guillaume


On 26 May 2015, at 15:37, Utkarsh Ayachit <utkarsh.ayachit at kitware.com<mailto:utkarsh.ayachit at kitware.com>> wrote:

Guillaume,

Use data information [1] as follows:

 UpdatePIpeline(inputPvts)
 extent = inputPvts.GetDataInformation().GetExtent()

See Section 3.3 from the ParView Guide[2] for more details.

Utkarsh

[1] http://www.paraview.org/ParaView3/Doc/Nightly/www/cxx-doc/classvtkPVDataInformation.html
[2] http://www.paraview.org/paraview-guide/



On Tue, May 26, 2015 at 8:07 AM, Guillaume Duclaux
<Guillaume.Duclaux at uib.no<mailto:Guillaume.Duclaux at uib.no>> wrote:
Hi,

I’ve been using a python script to post-process and visualise large structured grid files. It works great but the grids I am visualising are of different dimensions (let say either 512x128x512, or 1024x256x1024).

In the script pipeline - see snippet below -  I extract a subset (top cell layer in the Y direction) from the whole dataset, using ExtractSubset filter.

At this stage for the 2 input files dimensions above, I need to modify the script and correctly set extractSubset1.VOI values manually.

Is there a method that I could use in the script to get the dimensions (or extent) of the structured grid, so I can make the script extract the top layer I’m interested in for any grid dimension?


<snip>
from paraview.simple import *

   inputPvts = XMLPartitionedStructuredGridReader(FileName=[fname])
   inputPvts.PointArrayStatus = ['velocity']

   # get active view
   renderView1 = GetActiveViewOrCreate('RenderView')
   renderView1.ResetCamera()

   #get the 4 uppermost cells
   extractSubset1 = ExtractSubset(Input=inputPvts)
   extractSubset1.VOI = [0, 512, 127, 128, 0, 512]
   extractSubset1.SampleRateI = 1
   extractSubset1.SampleRateJ = 1
   extractSubset1.SampleRateK = 1
   extractSubset1.IncludeBoundary = 0
doCoolStuff...
</snip>

So far, I’ve tried reading the VOI from the extractSubsetFilter, but the indexing of the extent is not showing the grid dimensions:

   dimensions = extractSubset1.GetPropertyValue('VOI')
   print dimensions

But that returns an array [0, -1, 0, -1, 0, -1]. And I can’t seem to be able to use relative indexes in the filter like: extractSubset1.VOI = [0, -1, -2, -1, 0, -1].

Any thoughts?

Cheers

Guillaume







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