[vtkusers] Symmetry questions

[David Doria]

On Mon, Feb 8, 2010 at 5:17 PM, Banksie <banks at wai.com> wrote:

>
> Hi again,
>
> I'm a lot closer than I was, but I'm getting something a bit strange. When
> I
> apply symmetry to one axis, everything works fine, but when I move to
> having
> two axes with symmetry, I get a Seg Fault when it comes to the
>
> pRenderer->GetRenderWindow->Render();
>
> Command at the end of the code. I've attached the code below. Am I doing
> something silly?
>
> Thanks again
> Robbie
>
> void SnapshotView::slotSymmetry(const bool & flip, const int & axis)
> {
>        // Determine which axes are flipped
>        if(axis==xAxis) xFlipped=flip;
>        if(axis==yAxis) yFlipped=flip;
>        if(axis==zAxis) zFlipped=flip;
>
>        // Add a vtkTranform to apply symmetry to the dataset
>        vtkTransform * pTranslationX = vtkTransform::New();
>        vtkTransform * pTranslationY = vtkTransform::New();
>        vtkTransform * pTranslationZ = vtkTransform::New();
>
>        // Add a new vtkPolyDataMapper to deal with the new symmetrical data
>        vtkPolyDataMapper * pMapperSymm = vtkPolyDataMapper::New();
>        // Add a new vtkPolyData to deal with the new symmetrical data
>        vtkPolyData * pNewData = vtkPolyData::New();
>        // Add a new vtkAppendData to deal with the new symmetrical data
>        vtkAppendPolyData * pAppendData = vtkAppendPolyData::New();
>
>        // Create translation to data for given symmetry
>        pTranslationX->Translate(1.0, 0.0, 0.0);
>        pTranslationY->Translate(0.0, 1.0, 0.0);
>        pTranslationZ->Translate(0.0, 0.0, 1.0);
>
>        // Add the source data  pAppendData->AddInput(source->GetOutput());
> to our
> new vtkAppendData
>        pAppendData->AddInput(source->GetOutput());
>        vtkPolyData * pNewSourceData = source->GetOutput();
>
>        if(xFlipped){
>                // Apply translation filter to data for given symmetry
>                vtkTransformPolyDataFilter * pTransformFilter1 =
> vtkTransformPolyDataFilter::New();
>                pTransformFilter1->SetInput(pNewSourceData);
>                pTransformFilter1->SetTransform(pTranslationX);
>                pTransformFilter1->Update();
>
>                // Create a vtkPolyData set and add it to the
> vtkAppendPolyData for the
> symmetrical data
>                vtkPolyData * pData1 = pTransformFilter1->GetOutput();
>                pAppendData->AddInput(pData1);
>        }
>
>        if(yFlipped){
>                // Apply translation filter to data for given symmetry
>                vtkPolyData * pTempData = pAppendData->GetOutput();
>                vtkTransformPolyDataFilter * pTransformFilter2 =
> vtkTransformPolyDataFilter::New();
>                pTransformFilter2->SetInput(pTempData);
>                pTransformFilter2->SetTransform(pTranslationY);
>                pTransformFilter2->Update();
>
>                // Create a vtkPolyData set and add it to the
> vtkAppendPolyData for the
> symmetrical data
>                vtkPolyData * pData1 = pTransformFilter2->GetOutput();
>                pAppendData->AddInput(pData1);
>        }
>
>
>        if(zFlipped){
>                // Apply translation filter to data for given symmetry
>                vtkPolyData * pTempData2 = pAppendData->GetOutput();
>                vtkTransformPolyDataFilter * pTransformFilter3 =
> vtkTransformPolyDataFilter::New();
>                pTransformFilter3->SetInput(pTempData2);
>                pTransformFilter3->SetTransform(pTranslationZ);
>                pTransformFilter3->Update();
>
>                // Create a vtkPolyData set and add it to the
> vtkAppendPolyData for the
> symmetrical data
>                vtkPolyData * pData1 = pTransformFilter3->GetOutput();
>                pAppendData->AddInput(pData1);
>        }
>
> //      // Finally copy all the appended data to a new vtkPolyData set
>        pNewSourceData = pAppendData->GetOutput();
>
>        // Remap the data for display
>        pMapperSymm->SetInput(pNewSourceData);
>
>        // Add Mapper to Actor
>        pActor->SetMapper(pMapperSymm);
>
>        // Add Actor to renderer
>        pRenderer->AddActor(pActor);
>
>        // Reset camera
>        pRenderer->ResetCamera();
>        pRenderer->GetRenderWindow()->Render();
>
>        pTranslationX->Delete();
>        pTranslationY->Delete();
>        pTranslationZ->Delete();
>        pAppendData->Delete();
>        pNewData->Delete();
>        pNewSourceData->Delete();
> }
>
>
A quick thing, you should use
vtkSmartPointer<className> variableName = vtkSmartPointer<className>::New();
instead of
className* variableName = className::New();

Then you do not have to have the big block of Deletes()'s at the end of the
code :)

Can you make an post the simplest compilable example that demonstrates the
problem? It's much easier to debug if I can step through myself.

Thanks,

David
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