[vtkusers] Marching cubes with ITK data: Problems with negative indices, possible bug?

[Matthias Riechmann]

I changed to vtkContourFilter, now everything works fine. Is the 
marching cubes in VTK broken?


Matthias Riechmann schrieb:
> Hi,
> 
> I tried to create polgon models with marching cubes from ITK-data using 
> the ITK-VTK bridge. To force the marching cubes to close the polygons I 
> applied the "itk::ConstantPadImageFilter" on my original image data to 
> extend it by a couple of pixels. The way this filter does the job, is to 
> assign negative pixel coordinates (indices) in order not to have to 
> recalculate the image's origin.
> VTK's marching cube worked quite fine with it, ony on some images I 
> discovered a nasty phenomenon: The resulting polygon was split into 
> separate segments. This was not visible at first but after some 
> filtering holes startet to appear on the surface. A test using the 
> vtkConnectivityFilter showed the polydata really was split into several 
> pieces.
> Is it possible the ITK-VTK-bridge cannot handle the negative indices 
> properly? As a workaround I started extending my images using the 
> itk::PasteImageFilter, which which works out fine with the marching cubes.
> 
> 
> Matthias
> 
> 
> 
> 
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