[vtkusers] vtkAppendPolyData delete the scalars
Alex Malyushytskyy
alexmalvtk at gmail.com
Tue Aug 7 17:28:14 EDT 2012
> What additional information do you need?
To see that arrays are compatible you need to show details how both of
them are created, not 1
But you can check this yourself.
As far as I understand having both lines below do not make any sense, leave one
scalars->SetNumberOfValues(myPolyData->GetNumberOfCells());
// scalars->SetNumberOfTuples(myPolyData->GetNumberOfCells());
Correct way of casting instead of
>> static_cast<vtkIntArray*>(finalPolyData->GetCellData()->GetScalars());
would be
vtkIntArray* _array = vtkIntArray::SafeDownCast( .... );
even though arrays might be created and combined, I am not sure active
scalar would be set.
so I suggested you to check that array exist first:
finalPolyData->GetCellData()->GetArray( name )
And if it exist set the active scalar to newly created polydata
finalPolyData->SetActiveScalars( name );
o guessing does not work usually, so you need to find out what is wrong
the following line may crash the program only if finalPolyData or
GetCellData() is null which should not be the case
vtkDataArray * pA =finalPolyData->GetCellData()->GetScalars();
your code
vtkIntArray* scalarArray =
static_cast<vtkIntArray*>(finalPolyData->GetCellData()->GetScalars());
will crash it or produce garbage in the case when currently set scalar
is not type of vtkIntArray
also even though this is not a reason your code does not work,
remember the rule: every ::New() has to be paired with Delete() , in your code
vtkIntArray* scalars = vtkIntArray::New(); // never will be deleted
so I suggest you to add scalars->Delete() after
myPolyData->GetCellData()->SetScalars(scalars);
>>
>>
>> // replace the following line with line above
>> vtkIntArray* scalarArray =
>> static_cast<vtkIntArray*>(finalPolyData->GetCellData()->GetScalars());
>>
>
> This make the program crash, so there is nothng there.
>
On Tue, Aug 7, 2012 at 8:34 AM, Gonzalo Amadio <gonzaloamadio at gmail.com> wrote:
>
>
> 2012/8/7 Alex Malyushytskyy <alexmalvtk at gmail.com>
>>
>> If both polydata have exactly the same scalars (type, dimensions )
>> output should have a scalar field.
>> If it does not , it is a bug.
>
>
> myPolyData->GetNumberOfPoints() = 2421
> myPolyData->GetNumberOfCells() = 3010 (so the scalar array for this
> polydata is the same length)
>
> otherPolyData->GetNumberOfPoints() = 574
> otherPolyData->GetNumberOfCells() = 524
>
>
>>
>>
>> But I doubt it. You do not show all significant code, so
>> I am not sure these 2 scalars are compatible.
>
>
> What additional information do you need?
>
>>
>>
>> Did you want 1 scalar value per cell?
>> If so, could you try to replace
>>
>> vtkIntArray* scalars = vtkIntArray::New();
>> scalars->SetNumberOfComponents(1);
>> scalars->SetNumberOfValues(myPolyData->GetNumberOfCells());
>> scalars->SetNumberOfTuples(myPolyData->GetNumberOfCells());
>>
>> with
>>
>> vtkIntArray* scalars = vtkIntArray::New();
>> scalars->SetNumberOfValues( myPolyData->GetNumberOfCells());
>
>
> Yes, I want 1 scalar per cell, I tried this but didn't work.
>
>>
>>
>> if this does not help, or it is not what you want check what value (
>> if not null, what type of array ) the following line would return
>>
>> vtkDataArray * pA =finalPolyData->GetCellData()->GetScalars();
>>
>> // replace the following line with line above
>> vtkIntArray* scalarArray =
>> static_cast<vtkIntArray*>(finalPolyData->GetCellData()->GetScalars());
>>
>
> This make the program crash, so there is nothng there.
>
>>
>> Alex
>>
>> On Mon, Aug 6, 2012 at 2:18 AM, Gonzalo Amadio <gonzaloamadio at gmail.com>
>> wrote:
>> > Yes, what I wanted to mean with "is Strange" is that letting the input
>> > without appending works fine, so it means that it has its scalars.
>> > In other words, I printed the scalars of "otherPolyData" and
>> > "myPolyData"
>> > before appending, and I obtain desired results. So it means that they
>> > have
>> > scalars.
>> >
>> > So I don't know what is happening here. Maybe I have to add something
>> > more
>> > to satisfy conditions for using the filter, but I don't know.
>> > Some help?
>> >
>> > Thank you!
>> >
>> >
>> >
>> > 2012/8/3 Alex Malyushytskyy <alexmalvtk at gmail.com>
>> >>
>> >> >> appendGreenSubdAndRedBlue->AddInput(otherPolyData); // what is
>> >> >> extrange is that if I comment this line, it works fine
>> >> >> appendGreenSubdAndRedBlue->AddInput(myPolyData);
>> >>
>> >> there is nothing strange, if you comment this line there is no
>> >> modification were made,
>> >> so output is the same as input.
>> >>
>> >> why it removes scalar?
>> >> otherPolyData probably does not the same scalar. From documentation:
>> >>
>> >> "All geometry is extracted and appended, but point and cell attributes
>> >> (i.e., scalars, vectors, normals) are extracted and appended only if
>> >> all datasets have the point and/or cell attributes available. (For
>> >> example, if one dataset has point scalars but another does not, point
>> >> scalars will not be appended.)"
>> >>
>> >> Regards,
>> >> Alex
>> >>
>> >>
>> >> On Thu, Aug 2, 2012 at 4:25 AM, Gonzalo Amadio
>> >> <gonzaloamadio at gmail.com>
>> >> wrote:
>> >> > Hello everyone. Is there some reason whereby vtkAppendPolyData delete
>> >> > the
>> >> > scalars when I append 2 polydatas?
>> >> >
>> >> > Here is my code.
>> >> >
>> >> >> myPolyData->ShallowCopy(otherPolyData);
>> >> >> SubdividePolyData(myPolyData); /// Here I modified the
>> >> >> polydata,
>> >> >> so I need to assign it again the scalar array.
>> >> >>
>> >> >>
>> >> >>
>> >> >> // The problem I think is here in this lines, where I assign
>> >> >> the
>> >> >> scalar array
>> >> >> vtkIntArray* scalars = vtkIntArray::New();
>> >> >> scalars->SetNumberOfComponents(1);
>> >> >> scalars->SetNumberOfValues(myPolyData->GetNumberOfCells());
>> >> >> scalars->SetNumberOfTuples(myPolyData->GetNumberOfCells());
>> >> >>
>> >> >>
>> >> >>
>> >> >> for (int i = 0; i < myPolyData->GetNumberOfCells(); i++)
>> >> >> scalars->SetValue(i, 1);
>> >> >>
>> >> >>
>> >> >>
>> >> >> myPolyData->GetCellData()->SetScalars(scalars);
>> >> >>
>> >> >>
>> >> >>
>> >> >> vtkSmartPointer<vtkAppendPolyData> appendGreenSubdAndRedBlue
>> >> >> =
>> >> >> vtkSmartPointer<vtkAppendPolyData>::New();
>> >> >> appendGreenSubdAndRedBlue->AddInput(otherPolyData); // what is
>> >> >> extrange
>> >> >> is that if I comment this line, it works fine
>> >> >> appendGreenSubdAndRedBlue->AddInput(myPolyData);
>> >> >> appendGreenSubdAndRedBlue->Update();
>> >> >>
>> >> >>
>> >> >>
>> >> >> vtkPolyData * finalPolyData =
>> >> >> appendGreenSubdAndRedBlue->GetOutput();
>> >> >>
>> >> >>
>> >> >>
>> >> >> vtkIntArray* scalarArray =
>> >> >>
>> >> >> static_cast<vtkIntArray*>(finalPolyData->GetCellData()->GetScalars());
>> >> >> std::cout << scalarArray->GetNumberOfTuples() << std::endl;
>> >> >> //This line gives me an error
>> >> >
>> >> >
>> >> >
>> >> > The error that I obtain is the following :
>> >> >
>> >> > File : vtkAbstractArray.h - line 104
>> >> >
>> >> > vtkIdType GetNumberOfTuples()
>> >> > {return (this->MaxId + 1)/this->NumberOfComponents;}
>> >> >
>> >> > error:
>> >> >
>> >> > name type value
>> >> > this vtkAbstractArray * const 0x0
>> >> >
>> >> >
>> >> > I can assign "manually" again the scalars to the finalPolyData, but
>> >> > it
>> >> > is
>> >> > suppose that the scalars remains when I append them.
>> >> >
>> >> > Thank you!
>> >> >
>> >> > --
>> >> > --------
>> >> > Gonzalo
>> >> >
>> >> > _______________________________________________
>> >> > 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 VTK FAQ at:
>> >> > http://www.vtk.org/Wiki/VTK_FAQ
>> >> >
>> >> > Follow this link to subscribe/unsubscribe:
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>> >> >
>> >> _______________________________________________
>> >> 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 VTK FAQ at:
>> >> http://www.vtk.org/Wiki/VTK_FAQ
>> >>
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>> >
>> >
>> >
>> >
>> > --
>> > --------
>> > Gonzalo Amadio
>> >
>> _______________________________________________
>> 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 VTK FAQ at:
>> http://www.vtk.org/Wiki/VTK_FAQ
>>
>> Follow this link to subscribe/unsubscribe:
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>
>
>
>
> --
> --------
> Gonzalo Amadio
>
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