[Paraview-developers] object not displaying in the paraview window

[Chiranjib Sur]

Utkarsh and team,
Here I come again with a very similar question.

I am creating a object using a C++ class in ParaView. I have implemented
the RequestData function in the following way but I keep getting the error
message :

Input port 0 of algorithm MyClass(0x4961fc0) has 0 connections but is not
optional.

What is going wrong here?

Below is my implementation of RequestData

Thanks in advance,

Chiranjib


int MyClass::RequestData( vtkInformation*        vtkNotUsed( request ),
                                vtkInformationVector** vtkNotUsed(
inputVector ),
                                vtkInformationVector*  outputVector )
{
   // get the info object
    vtkInformation* outInfo = outputVector->GetInformationObject( 0 );

   // get the output
    vtkPolyData* output = vtkPolyData::SafeDownCast( outInfo->Get(
vtkDataObject::DATA_OBJECT()));



    vtkSmartPointer<vtkPolyData> polydata =
vtkSmartPointer<vtkPolyData>::New();

    vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
    points->SetDataType( VTK_DOUBLE ); // Set precision for the vtk points

 // generate my polydata with points etc.
....
//  at this stage polydata is generated

   output->ShallowCopy(polydata);
   output->Squeeze();

   return 1;
}

On Mon, Apr 27, 2015 at 3:37 PM, Chiranjib Sur <sur.chiranjib at gmail.com>
wrote:

> Wow, This works like a magic !
>
> Thank you very much for the solution and sorry for my delay in updating
> about the problem I mentioned.
>
> Chiranjib
>
> On Fri, Apr 17, 2015 at 5:54 PM, Utkarsh Ayachit <
> utkarsh.ayachit at kitware.com> wrote:
>
>> You're missing a call to `transformModel->Update()` before calling
>> `transformModel->GetOutput()`. The filter never updated, and hence its
>> output is empty.
>>
>> Utkarsh
>>
>> On Fri, Apr 17, 2015 at 6:34 AM, Chiranjib Sur <sur.chiranjib at gmail.com>
>> wrote:
>> > Hi All,
>> > I want to apply the tranform filter while I create an object in
>> paraview. TO
>> > try with I have overloaded vtkCubeSource class and can create the object
>> > which appears in the paraview pipeline and I can visualize the object
>> in the
>> > PV window.
>> >
>> > Now I want to apply the transformation filter (vtkTransform) to the
>> objct
>> > when I create it. To do that I have overloaded the RequestData function
>> like
>> > the following.
>> >
>> > The code is compiling and executing but when I create the object and
>> apply
>> > transform, nothing is appearing in the PV visualization window.
>> >
>> > Can anybody help me pointing out what is going wrong with my
>> implementation.
>> >
>> > I cam copying my code below
>> >
>> > Thanks,
>> > Chiranjib
>> >
>> >
>> > ------
>> >
>> >
>> >
>> > int MyOwnCubeSource::RequestData( vtkInformation *vtkNotUsed(request),
>> >
>> >                      vtkInformationVector **vtkNotUsed(inputVector),
>> >
>> >                      vtkInformationVector *outputVector)
>> >
>> > {
>> >
>> >   // get the info object
>> >
>> >   vtkInformation *outInfo = outputVector->GetInformationObject(0);
>> >
>> >
>> >
>> >   // get the ouptut
>> >
>> >   vtkPolyData *output = vtkPolyData::SafeDownCast(
>> >
>> >     outInfo->Get(vtkDataObject::DATA_OBJECT()));
>> >
>> > ....
>> >
>> > ....
>> >
>> >
>> >
>> > // output (type vtkPolyData) is already ready at this stage
>> >
>> >
>> >
>> > // If I don’t appy transform operation afterwards, I can visualize the
>> > object in the PV pipeline
>> >
>> >
>> >
>> >
>> >
>> > // -----------------------------------------------//
>> >
>> >
>> >
>> > // Implementation of vtkTransform starts here
>> >
>> >
>> >
>> >     double _rotationZ = 30.0;
>> >
>> >
>> >
>> > // Define transform
>> >
>> >     vtkSmartPointer<vtkTransform> transform =
>> > vtkSmartPointer<vtkTransform>::New();
>> >
>> >
>> >
>> >     // Define transformModel : transform filter
>> >
>> >     vtkSmartPointer<vtkTransformFilter> transformModel =
>> > vtkSmartPointer<vtkTransformFilter>::New();
>> >
>> >     transformModel->SetTransform(transform);
>> >
>> >
>> >
>> >     //Decoupling the pipeline and asking the transformfilter to update
>> the
>> > newpipeline (created out of shallowcopy)
>> >
>> >     vtkNew<vtkPolyData> cubeCopy;
>> >
>> >     cubeCopy->ShallowCopy(output);
>> >
>> >     transformModel->SetInputData(cubeCopy.GetPointer());
>> >
>> >
>> >
>> >     // Describe all the transform operations
>> >
>> >      transform->PostMultiply();
>> >
>> >      transform->RotateZ(10*_rotationZ);
>> >
>> >      transform->Update();
>> >
>> >
>> >
>> >      // getting the transformed output
>> >
>> >      vtkSmartPointer<vtkDataSet> transformedOutput =
>> > transformModel->GetOutput();
>> >
>> >
>> >
>> >      // Shallowcopy the transformed output to the old pipeline
>> >
>> >
>> >
>> >     output->ShallowCopy(transformedOutput);
>> >
>> >
>> >
>> > // A this stage "output" should be updated and the visualization
>> pipeline
>> > should show the transformed object
>> >
>> >
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