[vtkusers] converting vtkImageData to vtkUnstructuredGrid

[David Doria]

On Tue, Feb 8, 2011 at 7:05 PM, David E DeMarle
<dave.demarle at kitware.com> wrote:
> One way is to apply the threshold filter and set the threshold so that
> it includes the entire scalar range.

This kind of question comes up all way too often. In my opinion there
should be a filter to convert each VTK data type to every other type.
Sometimes the conversions would be "lossless" and other times lossy
(i.e. converting an unstructured grid with 3d cells to a polydata),
but it should still do something. Most of the time when people ask for
these conversions they want the obvious lossless one. By encapsulating
the "best practice conversion" into a filter, it makes it seem like
the right thing to do instead of a hack.

David