[vtkusers] vtkMarchingCubes does not work with vtkPolyData??

[Cory Quammen]

[cc'ing list]

Luca,

Inheritance from vtkPolyDataAlgorithm does not necessarily imply that
the algorithm takes vtkPolyData as input. In the case of
vtkMarchingCubes, you just need to pass in your filtered image data.
You might consider using vtkImageGaussianSmooth for smoothing your
data, or any one of the other filters starting with vtkImage* listed
at http://www.vtk.org/doc/nightly/html/classes.html.

As an aside, you are using the old style pipeline connections. It is
better to use the new style connections, such as:

m_smoother->SetInputConnection(m_input->GetOutputPort());
m_mc->SetInputConnection(m_smoother->GetOutputPort());

Hope this helps,
Cory

On 8/7/07, Luca Pamparana <luca.pamparana at gmail.com> wrote:
> Hi everyone,
>
> Looking at the documentation of the vtkMarchingCubes object, it inherits
> from vtkPolyDataAlgorithm. However, when I use the following filter
> pipeline, it fails with the error:
>
>  Input for connection index 0 on input port index 0 for algorithm
> vtkMarchingCubes(0x1753e60) is of type vtkPolyData, but a vtkImageData is
> required.
>
> The pipeline is as follows:
>
> // Convert the image data to polygons
> m_polyDataFilter->SetInput(m_input->GetOutput());
>
> m_polyDataFilter->SetOutputStyleToPolygonalize();
>
> // Smooth the data to remove the high frequencies and minmise the step
> effects
> m_smoother->SetInput(m_polyDataFilter->GetOutput());
>
> m_smoother->SetNumberOfIterations(50);
>
> // Pass this to the marching cube filter
>  m_mc->SetInput(m_smoother->GetOutput());
>
> This fails with the above error. Is it meant to be like this? Is there an
> easy way to convert polydata back to image data or alternatively smooth an
> image data with some filter.
>
> Thanks,
> Luca
>
>
>
>
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-- 
Cory Quammen
Department of Computer Science
University of North Carolina at Chapel Hill
http://www.cs.unc.edu/~cquammen