[vtkusers] vtkUnstructuredGridVolumeRayCastMapper (05B22CB8): Can't use the ray cast mapper without scalars!

[Ali Habib]

I tried your suggestion but it gave the same error


int shade = 0, compos = 0, interp = 0;

// renderer

vtkRenderer ^ren1 = gcnew vtkRenderer();

ren1->SetBackground(1.0, 1.0, 1.0);

// render window

// vtkRenderWindow renWin = new vtkRenderWindow();

// renWin.AddRenderer(ren1);

// renWin.SetSize(800, 600);

this->vtkFormsWindowControl1->GetRenderWindow()->AddRenderer(ren1);

vtkUnstructuredGrid ^grid = gcnew vtkUnstructuredGrid();

// interactor

vtkRenderWindowInteractor ^iren1 = gcnew vtkRenderWindowInteractor();

iren1->SetRenderWindow(this->vtkFormsWindowControl1->GetRenderWindow());

// set up the input file for unstructured grid reader

//1.Create a volume data

// create sphere geometry

vtkSphereSource ^sphere = gcnew vtkSphereSource();

sphere->SetRadius(1.0);

sphere->SetThetaResolution(18);

sphere->SetPhiResolution(18);

// grid.SetCells(new vtkTypeUInt16Array(),
sphere.GetOutput().GetCellData());

//2.Apply the tetrahedral mish

// vtkPolyData vp = new vtkPolyData();

// sphere.Update();

// grid.DeepCopy(sphere.GetOutputDataObject());

vtkDelaunay3D ^unstructuredReader = gcnew vtkDelaunay3D();

// this.vtkFormsWindowControl1.GetRenderWindow().get

// set up opacity transfer function

vtkPiecewiseFunction ^opacityTransferFunction = gcnewvtkPiecewiseFunction();

opacityTransferFunction->AddPoint(0, 0.02);

opacityTransferFunction->AddPoint(4095.0, 1.0);

 // set up color transfer function

vtkColorTransferFunction ^colorTransferFunction =
gcnewvtkColorTransferFunction();

colorTransferFunction->AddRGBPoint(0.0, 0.1, 0.1, 0.1);

colorTransferFunction->AddRGBPoint(4095.0, 1.0, 0.0, 1.0);

// set up volume property

vtkVolumeProperty ^volumeProperty = gcnew vtkVolumeProperty();

volumeProperty->SetColor(colorTransferFunction);

volumeProperty->SetScalarOpacity(opacityTransferFunction);

volumeProperty->SetInterpolationType(interp);

volumeProperty->SetShade(shade);

// Add scaler value

vtkDoubleArray ^arr = gcnew vtkDoubleArray();

arr->SetNumberOfTuples(unstructuredReader->GetOutput()->GetNumberOfPoints());

arr->FillComponent(0, 1.0); // e.g. double value = 1.0;

arr->SetName("myarray");

// MessageBox.Show(arr.GetData(

//unstructuredReader.GetOutput().GetPointData().SetScalars();

unstructuredReader->Update();

grid->DeepCopy(safe_cast<vtkDataObject^>(unstructuredReader->GetOutput()));

grid->GetPointData()->AddArray(arr);

grid->GetPointData()->SetScalars(arr);

// unstructuredReader.GetOutput().GetPointData().AddArray();

// unstructuredReader.GetOutput().GetPointData().

 // composite function for strucured grid renderer

vtkVolumeRayCastCompositeFunction ^compositeFunction =
gcnewvtkVolumeRayCastCompositeFunction();

compositeFunction->SetCompositeMethod(compos);

//unstructuredGridRendering

vtkUnstructuredGridVolumeRayCastMapper ^volumeUnstructedMapper =
gcnewvtkUnstructuredGridVolumeRayCastMapper();

//vtkVolumeRayCastMapper volumeUnstructedMapper = new
vtk.vtkVolumeRayCastMapper();

//volumeUnstructedMapper.set (compositeFunction);

volumeUnstructedMapper->SetInput(grid);

//volumeUnstructedMapper.SetScalarModeToUseCellData();

vtkVolume ^volume = gcnew vtkVolume();

volume->SetMapper(volumeUnstructedMapper);

volume->SetProperty(volumeProperty);

// add volume to renderer

ren1->AddVolume(volume);

this->vtkFormsWindowControl1->GetRenderWindow()->Render();

iren1->Start();

delete ren1;

this->vtkFormsWindowControl1->GetRenderWindow()->Dispose();

delete iren1;

delete opacityTransferFunction;

delete colorTransferFunction;

delete volumeProperty;

delete compositeFunction;

// unstructured grid case

delete volumeUnstructedMapper;

delete unstructuredReader;

delete volume;

delete grid;


On Mon, Oct 5, 2009 at 4:01 PM, Kevin H. Hobbs <hobbsk at ohiou.edu> wrote:

> On Tue, 2009-09-29 at 21:47 +0200, Ali Habib wrote:
> > I wrote a code to make tetrahedral mesh on sphere , but it no give
> > result except :
> >
> > ERROR: In m:\dev\cur\vtkdotnet\branch\50\VolumeRendering
> > \vtkUnstructuredGridVolumeRayCastMapper.cxx, line 274
> > vtkUnstructuredGridVolumeRayCastMapper (05B22CB8): Can't use the ray
> > cast mapper without scalars!
> >
> >
>
>
> You are trying to add a scalar array to the output of the vtkDelaunay3D
> filter.
>
> You cannot modify the output of a filter without disconnecting the
> output from the pipeline.
>
> I've never understood how to disconnect the output of a filter from the
> filter so I always just do :
>
> vtkUnstructuredGrid * my_grid = vtkUnstructuredGrid::New();
> filter->Update();
> my_grid->DeepCopy( filter->GetOutput() );
>
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