[Paraview] Python Programmable Filter

[David E DeMarle]

There is probably a python way to get help more easily, but one way to
figure it out is to look at the VTK doxygen documentation for
vtkDataObject and it's subclasses, and realize that all (or almost
all) of the public C++ methods are wrapped into python and therefore
available to use.

cheers,
Dave

On 11/13/08, Jacques Papper <jacques.papper at gmail.com> wrote:
> Thanks a lot Utkarsh !
>
> It works. I was almost there, but I couldn't figure out a way to expose the
> available interface for each object!
> Where am I supposed to look to figure out that CopyStructure(), and
> NewInstance(), SetBlock() etc ... are functions available ?
>
> Kind regards,
> Jacques Papper
>
>
> 2008/11/13 Utkarsh Ayachit <utkarsh.ayachit at kitware.com>
>
> > Jacques,
> >
> > Couple of ways to solve your problem:
> >
> > * Solution One:
> > If you don't want to deal with the fact that your data is a
> vtkMultiblockDataSet, apply the "Merge Blocks" filter after each of the
> "Extract Block" filters and then connect to the "Programmable Filter" to to
> the output from the "Merge Blocks" and then your current script should work
> just fine. The "Merge Blocks" will convert the vtkMultiBlockDataSet to a
> vtkUnstructuredGrid on which your script is applicable.
> >
> > * Solution Two:
> >
> > input0 = self.GetInputDataObject(0,0)
> > input1 = self.GetInputDataObject(0,1)
> > output = self.GetOutputDataObject(0)
> >
> > input0Block0 = input0.GetBlock(0)
> > input1Block0 = input1.GetBlock(0)
> >
> > output.CopyStructure(input0)
> > outputBlock0 = input0Block0.NewInstance()
> > outputBlock0.CopyStructure(input0Block0)
> > output.SetBlock(0, outputBlock0)
> >
> >
> outputBlock0.GetPointData().AddArray(input0Block0.GetPointData().GetArray("pressure1"))
> >
> outputBlock0.GetPointData().AddArray(input1Block0.GetPointData().GetArray("pressure2"))
> >
> > The above script will work if you are extracting a single block using the
> Extract Block filter. If you want to merge arrays for all the blocks in the
> input you'll have to iterate over the datasets in the vtkMultiblockDataset.
> Take a look at
> >
> http://www.paraview.org/Wiki/Python_Programmable_Filter#Dealing_with_Composite_Datasets
> >
> > Utkarsh
> >
> >
> > Jacques Papper wrote:
> >
> > >
> > > Here is what I am doing at the moment.
> > > -Load geometry 1
> > > -Extract wing block
> > >
> > > -Load geometry 2
> > > -Extract wing block
> > >
> > > Then use the resample filter with wing1 as input and wing2 as source
> > > (this works)
> > >
> > > The last bit is missing (that is merging the data from wing2 with the
> resampled data)
> > >
> > > Jacques
> > >
> > > 2008/11/13 Berk Geveci <berk.geveci at kitware.com
> <mailto:berk.geveci at kitware.com>>
> > >
> > >
> > >    Programmable filter can still be made to work. Do the datasets have
> > >    multiple parts? I am not sure how resampling would work with multiple
> > >    parts. It is impossible to guess which parts map to which parts...
> > >
> > >    -berk
> > >
> > >    On Thu, Nov 13, 2008 at 8:28 AM, Jacques Papper
> > >
> > >    <jacques.papper at gmail.com
> <mailto:jacques.papper at gmail.com>> wrote:
> > >     > They are multi-block datasets from Ensight Reader.
> > >     > Is there another way of dealing with this then ?
> > >     > Jacques
> > >     >
> > >     > 2008/11/13 Berk Geveci <berk.geveci at kitware.com
> > >    <mailto:berk.geveci at kitware.com>>
> > >
> > >     >>
> > >     >> Are the inputs multi-block datasets by any chance?
> > >     >>
> > >     >>
> > >     >> -berk
> > >     >>
> > >     >> On Thu, Nov 13, 2008 at 6:03 AM, Jacques Papper
> > >
> > >     >> <jacques.papper at gmail.com
> <mailto:jacques.papper at gmail.com>> wrote:
> > >     >> > Hi Berk,
> > >     >> >
> > >     >> > I am trying out your suggestion of merging arrays :
> > >     >> >
> > >     >> > input0 = self.GetInputDataObject(0,0)
> > >     >> > input1 = self.GetInputDataObject(0,1)
> > >     >> > output = self.GetOutputDataObject(0)
> > >     >> >
> > >     >> >
> > >
> output.GetPointData().AddArray(input0.GetPointData().GetArray("pressure1"))
> > >     >> >
> > >     >> >
> > >
> output.GetPointData().AddArray(input1.GetPointData().GetArray("pressure2"))
> > >     >> >
> > >     >> > but I get the following error message :
> > >     >> >
> > >     >> >   File "<string>", line 2, in <module>
> > >     >> >   File "<string>", line 4, in RequestData
> > >     >> > AttributeError: GetPointData
> > >     >> >
> > >     >> > I also tried just using the programmable filter on one source
> > >    and with
> > >     >> > the
> > >     >> > following code, and  I get the same error :
> > >     >> >
> > >     >> > input0=self.GetInputDataObject(0,0)
> > >     >> > input0.GetPointData()
> > >     >> >
> > >     >> > I am using version 3.4.0
> > >     >> >
> > >     >> >
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> > >
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> > >     >> >
> > >     >> >
> > >     >
> > >     >
> > >
> > >
> > >
> > >
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-- 
David E DeMarle
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x109