[Paraview] Inaccurate results with Probe filter

[Magician]

Sorry.
I forgot to add an address of PV mailing list.


Magician


On 2013/03/20, at 10:33, Magician wrote:

> Hi Tony,
> 
> 
> I discussed similar problems.
> <http://www.paraview.org/pipermail/paraview/2012-June/025273.html>
> 
> The interpolation and integration method (both space and time domain)
> of ParaView are very simple, but not ideal.
> ParaView splits all cells into tetrahedra or triangle and
> interpolate values with linear algorithm.
> I haven't research FIELDVIEW's method yet, but it may be different from PVs.
> 
> 
> Magician
> 
> 
> On 2013/03/20, at 4:13, paraview-request at paraview.org wrote:
> 
>> Hi Tony,
>> 
>> What kind of cells are these? Can you make the data available to us?
>> 
>> -berk
>> 
>> 
>> On Tue, Mar 19, 2013 at 12:16 PM, Tony McDaniel <tonymcdaniel at gmail.com>wrote:
>> 
>>> I'm using the Probe Location filter to extract data from a 3D CFD solution
>>> for an internal flow, and I'm not getting the data that I should be for
>>> some (but not all) of the points. The dataset is approximately 7 million
>>> nodes saved in Ensight format.
>>> 
>>> I'm comparing the data returned by Paraview to the data at the same
>>> locations in FieldView. For licensing reasons, I would prefer to use
>>> Paraview for this research, but I also need accurate solutions.
>>> 
>>> For two representative probe locations, I have the following results:
>>> x       y       z       pv_density  fv_density  pv_pressure fv_pressure
>>> 0.3912    -0.0376    -0.0566    0.9040      0.9040        67779.9
>>> 67779.9
>>> 0.3912    -0.0426    -0.0516    0.8275      0.8623        65849.0
>>> 66176.3
>>> 
>>> The first point matches precisely between Paraview and FieldView. However,
>>> the second point is substantially different. In addition, the velocity at
>>> point two is {0,0,0} indicating that the point is on the boundary, though
>>> it is not actually.
>>> 
>>> Looking at color plots in Paraview, the color under the point location
>>> clearly matches the numbers from FieldView. I've uploaded plots showing
>>> pressure in the plane containing the two locations here:
>>> https://dl.dropbox.com/u/**744216/probe1.png<https://dl.dropbox.com/u/744216/probe1.png>
>>> https://dl.dropbox.com/u/**744216/probe2.png<https://dl.dropbox.com/u/744216/probe2.png>
>>> 
>>> The values are wrong for points that are close to the boundary, and match
>>> FieldView for points away from the boundary. I have also tried importing
>>> the locations from a CSV file and using the Resample Dataset and get the
>>> same values.
>>> 
>>> Can anyone shed light on why this is happening?
>