[vtkusers] VTK Threshold Discrepancy

[Cory Quammen]

Hi Eric,

I don't know if you are still working on this, but would it be possible to
send me a dataset and compilable code sample to try to replicate this
problem?

Thank you,
Cory

On Wed, Nov 11, 2015 at 11:11 AM, Eric D. Robertson <
eric.robertson at cfdrc.com> wrote:

> Thank you for the reply. However, that seems to not have an effect. Here
> is my snippet of code
>
>
> threshold->SetInputData(unstructuredGrid);
> threshold->SetInputArrayToProcess(0, 0, 0,
> vtkDataObject::FIELD_ASSOCIATION_POINTS, "Flag");
> threshold->ThresholdByUpper(1); //Cut off everything that isn't Flag = 1
>
> threshold->AllScalarsOff();
>
> threshold->Update();
>
>
>
> There are 20402 original points in "unstructuredGrid."
>
> There are 16492 points after thresholding.
> However, there are 16495 points designated with Flag = 1 in
> "unstructuredGrid."
>
> Eric Robertson
> Research Engineer, BET
> CFD Research Corporation
> 701 McMillian Way NW, Suite D
> Huntsville, AL 35806
> Ph: 256-726-4912
> Email:  eric.robertson at cfdrc.com
>
>
> <eric.robertson at cfdrc.com>
> ------------------------------
> *From:* Cory Quammen [cory.quammen at kitware.com]
> *Sent:* Tuesday, November 10, 2015 4:58 PM
> *To:* Eric D. Robertson
> *Cc:* vtkusers at vtk.org
> *Subject:* Re: [vtkusers] VTK Threshold Discrepancy
>
> Eric,
>
> Try unchecking the "All Scalars" option in the Threshold filter
> properties.
>
> HTH,
> Cory
>
> On Tue, Nov 10, 2015 at 5:47 PM, Eric D. Robertson <
> eric.robertson at cfdrc.com> wrote:
>
>> I am using vtkThreshold to filter point data stored as vtkStructuredGrid.
>>
>>
>>
>> The data is essentially an array of 0’s and 1’s, where I am looking to
>> only keep the cells with 1’s stored.
>>
>>
>>
>> When I apply the vtkThreshold, the result is a domain slightly smaller
>> than the number of cells with 1’s. In other words, the number of cells in
>> the vtkThreshold doesn’t exactly match up to the number of 1’s available in
>> the original unthresholded domain. Is this a known issue?
>>
>>
>>
>>
>>
>>
>>
>> Eric Robertson
>>
>> Research Engineer, BET
>>
>> CFD Research Corporation
>>
>> 701 McMillian Way NW, Suite D
>>
>> Huntsville, AL 35806
>>
>> Ph: 256-726-4912
>>
>>
>>
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>
>
> --
> Cory Quammen
> R&D Engineer
> Kitware, Inc.
>



-- 
Cory Quammen
R&D Engineer
Kitware, Inc.
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