[Paraview] Contours of integer array

Mon Jul 11 09:13:18 EDT 2016

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

On Mon, Jul 11, 2016 at 8:44 AM, Schlottke-Lakemper, Michael <
m.schlottke-lakemper at aia.rwth-aachen.de> wrote:

> Hi David,
>
> ah, ok. However, in this case I’m wondering what I am doing wrong here: If
> I use the Extract Region Surface filter, my dataset looks just like before.
> Do I need to create an array with a certain name that contains the
> information on which the regions are extracted? And does this work also for
> 2D (unstructured grid with vtkQuads) or only in 3D?
>
>
You don't need a particular named array, but you do need to change the
"Region Array Name" from "material" to
"name-or-your-cell-aligned-integer-valued-material-array".

Darn. Looks like there is a bug somewhere in
vtkDataSetRegionSurfaceFilter's treatment of 2D cells. Please file a bug
report and reference this conversation in the report to help reproduce.

In the attached state file, change Mandelbrot1's extent from 0,25 0,25,
0,25 to 0,25 0,25, 0,0 to demonstrate.

> Sorry for being so slow :-/
>
>
Not at all.

> Michael
>
> On 11 Jul 2016, at 14:29 , David E DeMarle <dave.demarle at kitware.com>
> wrote:
>
> Extract region surface will do all domains at the same time.
>
> What it does is iterate over all cells and extract the faces of the cell
> for which either their is no neighbor or the neighbor cell has different
> material.
>
>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
> On Mon, Jul 11, 2016 at 8:25 AM, Schlottke-Lakemper, Michael <
> m.schlottke-lakemper at aia.rwth-aachen.de> wrote:
>
>> Hi David,
>>
>> Thanks for your answer. From what I understand, your suggestions allow me
>> to extract the surface for a single domain. However, what I am really
>> looking for is something like in the second example, i.e., where I get
>> lines representing the domain boundaries between *all* domains at once. I
>> just want them to align neatly with the actual boundaries and not have them
>> diluted by the Cell-to-Point filter. Any idea how I can achieve that? Or
>> maybe I just misunderstood you…
>>
>> Michael
>>
>> On 11 Jul 2016, at 13:37 , David E DeMarle <dave.demarle at kitware.com>
>> wrote:
>>
>> Could try threshold, or nearly equivalently clip by scalar, followed by
>> surface filter.
>>
>> Another option is the material interface filter. That requires
>> unstructured grid input and an integer or idtype material array. Clip its
>> output or use opacity to see inside since its external surface looks the
>> same as its input's.
>> On Jul 11, 2016 6:41 AM, "Schlottke-Lakemper, Michael" <
>> m.schlottke-lakemper at aia.rwth-aachen.de> wrote:
>>
>>> Maybe some visualization might help to illustrate the problem. This is
>>> what the domain decomposition looks like for two domains:
>>>
>>> <PastedGraphic-1.png>
>>>
>>> There are only two domains with values 0 and 1, respectively. I then
>>> select & apply the “Cell Data to Point Data” filter, then the “Contour”
>>> filter with only one isosurface set to “0.5”. However, in this example, the
>>> result is a blank screen, i.e., no visible output from the Contour filter.
>>>
>>> In another example, I get the following result:
>>> <PastedGraphic-2.png>
>>>
>>> The sharp, colored interfaces of the integer array in the back is
>>> clearly visible. In this case, there are 5 domains (values [0,4]) and I
>>> used 0.5, …, 3.5 as the isosurface values in the contour filter. While in
>>> this case I actually get an output (white lines), they follow the fuzzy
>>> output of “Cell Data to Point Data” and I am not able to reconstruct the
>>> sharp interfaces.
>>>
>>> To conclude, my problems are actually twofold: I would like to find out
>>> how to restore sharp contours, and - if that does not work - at least how
>>> to make this approach work for all datasets I am looking at.
>>>
>>> Again, thanks a lot in advance, and please excuse my double posting...
>>>
>>> Michael
>>>
>>> On 11 Jul 2016, at 12:16 , Schlottke-Lakemper, Michael <
>>> m.schlottke-lakemper at aia.rwth-aachen.de> wrote:
>>>
>>> Hi folks,
>>>
>>> I would like to visualize an integer array of an unstructured dataset
>>> based on voxels, which contains MPI rank ids generated by a filter we use.
>>> To achieve this, I plan to somehow extract the “sharp” interfaces, similar
>>> to what the contour filter does, to obtain a visual representation of the
>>> domain decomposition. However, for the contour filter, I first have to call
>>> “Cell data to point data”, which smears out the previously sharp interfaces
>>> and causes connectivity problems of the resulting contours, as in some
>>> areas the domain decomposition features are very small.
>>>
>>> Is there another way how I could extract these contours? Please note
>>> that I am not using vtkProcessId but rather an own integer array.
>>>
>>> Thanks a lot in advance
>>>
>>> Michael
>>>
>>>
>>> --
>>> Michael Schlottke-Lakemper
>>>
>>> Institute of Aerodynamics and Chair of Fluid Mechanics
>>> RWTH Aachen University
>>> Wüllnerstraße 5a
>>> 52062 Aachen
>>> Germany
>>>
>>> Phone: +49 (241) 80 95188
>>> Fax: +49 (241) 80 92257
>>> Mail: m.schlottke-lakemper at aia.rwth-aachen.de
>>> Web: http://www.aia.rwth-aachen.de
>>>
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>>> Powered by www.kitware.com
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>>> Visit other Kitware open-source projects at
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>>> Please keep messages on-topic and check the ParaView Wiki at:
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>>
>
>
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