[vtkusers] Convert vtkActor to vtkPolyData

[Cory Quammen]

You are trying to downcast a vtkAlgorithm to a vtkPolyData, but
vtkPolyData does not descend from vtkAlgorithm, so it won't work.

Instead, try

refLower = vtkPolyData::SafeDownCast(actorLower->GetMapper()->GetInputAsDataSet())

Let us know how it goes.

Cory

On Sun, Mar 2, 2014 at 4:01 AM, Agata Krasoń <agatakrason at gmail.com> wrote:
> Hi,
>
> I need to convert vtkActor to vtkPolyData and save as stl file.
>
> I followed ReverseAccess example from VTK wiki
> http://www.vtk.org/Wiki/VTK/Examples/Cxx/Visualization/ReverseAccess
> Unfortunately  it does not work in this case.
>
> I am trying with following code :
> I don't know exactly about SafeDownCast
> It seems to be that I am doing something wrong in SafeDownCast  ..
>
> .....
>   actorLower = vtkSmartPointer<vtkActor>::New();
>   actorUpper = vtkSmartPointer<vtkActor>::New();
>
>  vtkSmartPointer<vtkAlgorithm> algoSafeLower =
> actorLower->GetMapper()->GetInputConnection(0, 0)->GetProducer();
>   refLower = vtkPolyData::SafeDownCast(algoSafeLower));
>
> vtkSmartPointer<vtkAlgorithm> algoSafeUpper =
> actorUpper->GetMapper()->GetInputConnection(0, 0)->GetProducer();
>   refUpper = vtkPolyData::SafeDownCast(algoSafeUpper);
>
>   safeAppendFilter = vtkSmartPointer<vtkAppendPolyData>::New();
>   safeAppendFilter->AddInput(refUpper);
>   safeAppendFilter->AddInput(refLower);
>   safeAppendFilter->Update();
>
>   stlWriter = vtkSmartPointer<vtkSTLWriter>::New();
>   stlWriter->SetFileName("output_file.stl");
>   stlWriter->SetInputConnection(safeAppendFilter->GetOutputPort());
>   stlWriter->Write();
>
> I would appreciate for any help please.
>
> agatte
>
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