[vtkusers] Voxelization

[KS Jothybasu]

What about creating a mesh with vtkDelaunay3D?

Jothy

On Wed, Mar 10, 2010 at 1:30 AM, Daniel Soares <adaptchart.info at gmail.com>wrote:

> Hi!
>
> I have a problem with voxelization in VTK. My purpose is to create a sphere
> using vtkSphereSource, then voxelize it using vtkVoxelModeller, then draw a
> surface that is similar to the original sphere. The only way I managed to
> draw a surface, was using vtkContourFilter. The problem is that some
> artifacts are produced, looking like holes in the voxelized sphere.
> I saw at this site ( http://www.evl.uic.edu/aspale/cs526/final/3-5-2-0.htm ),
> that the results with vtkMarchingCubes are much better than the ones with
> vtkContourFilter. So I tryied to use it, but I couldn't obtain any result at
> all (blank screen). The same happened when I used vtkDiscreteMarchingCubes
> and vtkImageMarchingCubes.
>
> Does anyone have any idea why the marching cubes are not producing results
> or why the contour filter produces holes on the surface? Is there other way
> to achive what I want?
>
> Here's the source code of my experiment:
>
> //===============================================
>
> vtkSphereSource* sphereModel = vtkSphereSource::New();
> sphereModel->SetThetaResolution(10);
> sphereModel->SetPhiResolution(10);
>
> vtkVoxelModeller* voxeller = vtkVoxelModeller::New();
> voxeller->SetSampleDimensions(17, 17, 17);
> voxeller->SetModelBounds(-0.5, 0.5, -0.5, 0.5, -0.5, 0.5);
> voxeller->SetInputConnection(sphereModel->GetOutputPort());
> voxeller->Update();
> vtkImageData* imageData = voxeller->GetOutput();
> imageData->SetScalarTypeToFloat();
>
> vtkLookupTable* lut = vtkLookupTable::New();
> lut->SetNumberOfColors(3);
> lut->SetTableRange(0, 1);
> lut->SetScaleToLinear();
> lut->Build();
> lut->SetTableValue(0, 0, 0, 0, 1);
> lut->SetTableValue(0.5, 1, 0, 0, 1);
> lut->SetTableValue(1, 1, 1, 1, 1);
>
> //vtkContourFilter* surface = vtkContourFilter::New();
> vtkMarchingCubes* surface = vtkMarchingCubes::New();
> surface->SetInput(imageData);
> surface->ComputeScalarsOn();
> surface->ComputeGradientsOn();
> surface->ComputeNormalsOn();
> surface->SetValue(0, 0.5);
>
> vtkPolyDataMapper* voxelMapper = vtkPolyDataMapper::New();
> voxelMapper->SetInputConnection(discrete->GetOutputPort());
> voxelMapper->SetLookupTable(lut);
> voxelMapper->SetScalarRange(0, lut->GetNumberOfColors());
>
> vtkActor* voxelActor = vtkActor::New();
> voxelActor->SetMapper(voxelMapper);
>
> ren1->AddActor(voxelActor);
>
> //==============================================
>
> Thanks in advance.
>
> Daniel Soares
>
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