[Insight-developers] itkVTKPolyDataReader.h reads ascii only--- why?

[brian avants]

Vince --- My understanding (though perhaps outdated?) is that vtk
meshes lose direction information (obtained by calling GetDirection on
an itk image) b/c a vtk image does not store this information.  So, if
you create a pipeline like this:

ITK-Image =>  VTK-Image => MarchingCube => VTK-Mesh => ITK-Mesh

then you will lose the directionality information at the ITK to VTK
stage.  Which is a problem if the direction is not the identity. The
mesh, consequently, doesnt have orientation either, unless you
explicitly set it yourself (not hard to do) by mapping the vtk-points
through the orienting transformation.  So, maybe there is a filter
that already does this or perhaps the vtk image object is updated and
now stores the orientation?   Or maybe there's another vtk filter that
should be inserted into the pipeline above to reorient the output of
marching cubes back into ITK physical space?

B


On Tue, Oct 19, 2010 at 10:55 PM, Magnotta, Vincent A
<vincent-magnotta at uiowa.edu> wrote:
> Brian,
>
> I don't understand this question. Isn't the VTK point information already in
> physical space? Maybe this is just how I have always dealt with the VTK
> data. I believe that Slicer also follows this convention.
>
> Vince
>
>
> ----------------------
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>
>
>
> -----Original Message-----
> From: insight-developers-bounces at itk.org on behalf of brian avants
> Sent: Tue 10/19/2010 2:57 PM
> To: Alexandre GOUAILLARD
> Cc: Insight-developers at itk.org; Luis Ibanez
> Subject: Re: [Insight-developers] itkVTKPolyDataReader.h reads ascii only---
> why?
>
> Hi Alexandre, Wanlin , dev-list
>
> Would it be possible to add a reference image space to the vtk reader?
>  That is, because vtk files dont have physical space associated with
> them, we could have an optional input to the filter that would
> reorient the mesh using the space of the image from which the mesh was
> originally derived.  I guess this should probably be a separate
> unoriented to oriented mesh filter ... have you already resolved this
> issue?
>
> Brian
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