[Paraview] How to generate/access Points array from vtkImageData Inbox

[David E DeMarle]

You should come up with numpy expression that derives each point's location.

vtkImageData's point locations are implicitly determined by the image data's
origin, extent, and spacing.

David E DeMarle
Kitware, Inc.
R&D Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909


On Thu, Oct 25, 2012 at 2:37 PM, Gang Song <songgang97 at gmail.com> wrote:
> Hi,
>
> I am writing a Python programmable filter in Paraview. The input
> source is a type of vtkImageData. I want to get the coordinates of all
> the points and use them to generate an output of type
> vtkStructuredGrid. Currently I am using a for loop:
>
> pdi = self.GetInput()
> pdo = self.GetOutput()
>
> numPts = pdi.GetNumberOfPoints()
> points = vtk.vtkPoints()
> points.Allocate(numPts, numPts)
>
> for i in xrange(numPts):
>         point = pdi.GetPoint(i)
>         # ...
>         # other manipulations on point
>         # ...
>         points.InsertNextPoint(point)
>
> # ...
> pdo.SetDimensions(pdi.GetDimensions())
> pdo.SetPoints(points)
>
>
> My problem is that for loop became very slow for large image volumes.
> So I am replacing it with numpy. But I couldn't find a way to get
> points array directly from vtkImageData, something like:
>
> points = pdi.Points
> points = points * 0.5
> newPoints.SetData(numpyTovtkDataArray(points))
>
>
> It seems that there is no internal points array stored in
> vtkImageData. Is there a easy way to do this?
>
>
> Thanks
>
> Gang
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