[Paraview] non-symmetric representation of symmetric field

Tue May 27 12:34:34 EDT 2014

Hi Mikhail,

Maybe the usage of Resample With Dataset is wrong.
You should set the input (VTS) and source (Plane) on the Change Input Dialog correctly.

Try the attached state file.

Magician

On May 27, 2014, at 2:34, Mikhail Artemyev <artemiev.mikhail at gmail.com> wrote:

> Dear Magician,
> 
> Here is a precise algorithm I follow to:
> 
> 1. Read the data (I usually do that in terminal: paraview test.vts) (test.vts is attached)
> 2. Sources -> Plane (Origin: 0 0 0, Point1: 4 0 0, Point2: 0 2 0, X Resolution: 200, Y Resolution: 100)
> 3. Filters -> Resample With Dataset -> (Available input ports: Source; Select Input: Plane1) (test.pvsm is attached)
>    (After applying this filter I get nothing)
> 4. Repeating step 3 with exactly the same parameters (if I remember correctly) gave me the desired result once. But now it doesn't. Nevertheless test2.pvsm, corresponding to the state after doing this, is attached.
> 
> Thank you for your help!
> 
> Best regards,
> Mikhail
> 
> 
> 
> On 05/23/2014 06:18 PM, Magician wrote:
>> Hi Mikhail,
>> 
>> 
>> I need to get more information about your problem.
>> Can you share your dataset or screenshot?
>> .pvsm state files are more suitable.
>> 
>> 
>> Magician
>> 
>> 
>> On May 24, 2014, at 5:33, Mikhail Artemyev <artemiev.mikhail at gmail.com> wrote:
>> 
>>> Dear Magician,
>>> 
>>> Thank you for the explanation and for the hint!
>>> The only issue is that the last step of your algorithm
>>>   3. apply Resample With Dataset filter,
>>> not always gives the desired result.
>>> I was able to get the same representation like you showed, but
>>> it was an accidental choice of several Resample With Dataset filters,
>>> and I couldn't repeat it again. My impression is that I have to apply
>>> this filter several times to different sources. Am I right?
>>> 
>>> Thank you.
>>> 
>>> Best regards,
>>> Mikhail
>>> 
>>> 
>>> On 05/17/2014 12:00 AM, Magician wrote:
>>>> Hi Mikhail,
>>>> 
>>>> 
>>>> Yes, that’s because of the triangulation (or tesselation) of surface representations.
>>>> Most of the 3D programs including ParaView draw objects as groups of triangles.
>>>> That’s depends on today’s 3D rendering pipelines such as OpenGL, DirectX, etc.
>>>> Please googling the keywords: ‘vertex shading’
>>>> 
>>>> Even though you read your data as structured grid with point values,
>>>> ParaView should immediately triangulate all of the rectangles, and interpolating
>>>> the values between points of the triangles.
>>>> 
>>>> # If you visualize cell values, there are no problem caused by interpolating.
>>>> 
>>>> The attached image is one of the solution.
>>>> 1. read your data
>>>> 2. make a ‘fine resolution' Plane source with same size to the original (for example, 200x100 structured grid)
>>>> 3. apply Resample With Dataset filter
>>>> The result looks nearly-symmetric for me.
>>>> 
>>>> 
>>>> Magician
>>>> 
>>>> 
>>>> On May 17, 2014, at 10:40, paraview-request at paraview.org wrote:
>>>> 
>>>>> Date: Fri, 16 May 2014 20:40:18 -0500
>>>>> From: Mikhail Artemyev <artemiev.mikhail at gmail.com>
>>>>> To: paraview at paraview.org
>>>>> Subject: [Paraview] non-symmetric representation of symmetric field
>>>>> Message-ID: <5376BE02.7050800 at gmail.com>
>>>>> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>>>>> 
>>>>> Dear all,
>>>>> 
>>>>> Here is a minimal example of values distributed over a mesh:
>>>>> 
>>>>> 0------0------0------0------0
>>>>> |        |        |         |        |
>>>>> 0----0.5---0.75---0.5-----0
>>>>> |        |        |         |        |
>>>>> 0------0------1------0------0
>>>>> 
>>>>> To visualize this field I wrote a .vts file:
>>>>> 
>>>>> <?xml version="1.0"?>
>>>>> <VTKFile type="StructuredGrid" version="0.1" byte_order="LittleEndian">
>>>>>   <StructuredGrid WholeExtent="1 5 1 3 1 1">
>>>>>     <Piece Extent="1 5 1 3 1 1">
>>>>>       <PointData Scalars="scalars">
>>>>>         <DataArray type="Float64" Name="sol_" format="ascii">
>>>>> 0 0 1 0 0 0 0.5 0.75 0.5 0 0 0 0 0 0
>>>>>         </DataArray>
>>>>>       </PointData>
>>>>>       <Points>
>>>>>         <DataArray type="Float64" NumberOfComponents="3" format="ascii">
>>>>> 0 0 0
>>>>> 1 0 0
>>>>> 2 0 0
>>>>> 3 0 0
>>>>> 4 0 0
>>>>> 0 1 0
>>>>> 1 1 0
>>>>> 2 1 0
>>>>> 3 1 0
>>>>> 4 1 0
>>>>> 0 2 0
>>>>> 1 2 0
>>>>> 2 2 0
>>>>> 3 2 0
>>>>> 4 2 0
>>>>>         </DataArray>
>>>>>       </Points>
>>>>>     </Piece>
>>>>>   </StructuredGrid>
>>>>> </VTKFile>
>>>>> 
>>>>> The visual representation of this field, however, doesn't look symmetric 
>>>>> (a figure is attached),
>>>>> although the values are symmetric with respect to a Y-axis crossing the 
>>>>> center of the domain.
>>>>> 
>>>>> Could you please shed some light on where I am wrong -
>>>>> in my understanding of visualization technique, or in a way I pass the 
>>>>> data to ParaView?
>>>>> I use ParaView 4.1.0 64-bit, Linux.
>>>>> 
>>>>> Thank you.
>>>>> Best regards,
>>>>> Mikhail
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