[vtkusers] unstructured grid + tetrahedrons

[Baliki B.]

I tried vtkShrinkFilter and it worked.  My question is why using
vtkShrinkFilter and pressing w key shows tetrahedrons and without it(e.g.
using the original unstructured grid) doesn't? Is it something with the fact
you say it results in "polydata" ?

Why you give emphasis in "results in polydata" in both first two methods
(vtkShrinkFilter and vtkExtractGeometry) ? Is something "wrong" the polydata
we get?

Also, i read in the book that polydata is types(vertices, lines, polygons
and triangle strips) which is limited and that's why we use unstructured
grid to represent a tetrahedron.
Am i missing something?

2009/12/10 Dominik Szczerba <dominik at itis.ethz.ch>

> Unfortunately, I will not have a possibility to write those examples this
> time. A few quick comments follow below.
>
>
> David Doria wrote:
>
>> On Thu, Dec 10, 2009 at 8:52 AM, Baliki B. <balikivtk at gmail.com> wrote:
>>
>>> Could you explain (with some code) a little bit more?
>>>
>>>
>>> 2009/12/10 Dominik Szczerba <dominik at itis.ethz.ch>
>>>
>>>> You can see your tets in multiple ways:
>>>>
>>>> - extract cells by region
>>>>
>>>
> There is a filter (vtkExtractGeometry) to extract parts of a volume mesh
> NOT cutting the cells. Resulting is a polydata of course, but you see the
> inside cells otherwise hidden. Combined with an interactive widget (e.g.
> vtkBoxWidget) and edge visibility it gives a very good view.
>
>  - cell shrinking
>>>>
>>>
> You can shrink all the cells by a factor (vtkShrinkFilter). This will
> result in a polydata again, but you will see the separate cells (by their 4
> shrinked triangles).
>
>
>
>>>> To see the associated data:
>>>> - volume rendering
>>>>
>>>
> see vtkVolume
>
>  - cut slices
>>>>
>>>
> see vtkCutter
>
>  - clip
>>>>
>>>
> see vtkClipDataSet
>
>  - contouring
>>>>
>>>
> see vtkContourFilter
>
> Dominik
>
>
>
>>>> Dominik
>>>>
>>>>
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>>>
>> It's sounding like this may call for a couple of examples...
>>
>> Thanks,
>>
>> Captain Example
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>
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