Hi, Sam, Would you mind reposting this? The pdf file seems corrupt. thanks, Leo
On Sun, Jun 10, 2012 at 7:38 PM, Samuel Key <[email protected]> wrote: > Hi Leo, > > Though likely more arithmetically intense than you would like, I have > attached a 3-page write-up on how to do an exact integration over the > surface of a bi-linear isoparametric coordinate based quadrilateral in > three-space. It is easily adapted to a flux integration as well. > > If it helps, please free to incorporate it into ParaView. > > Sam Key. > > > > > On 6/10/2012 12:55 PM, Yuanxin Liu wrote: > > Hi, > This is not really a bug, but just what the linear precision > integration does. As you can see in vtkIntegrateAttributes.cxx:215, the > quad cell is basically cut into two triangles along a diagonal, integration > is done for each triangle and the results are added up. So, depending > where your "1" falls on a diagonal vertex, you will get different results. > > Leo > > > On Sat, Jun 9, 2012 at 8:57 AM, Magician <[email protected]> wrote: > >> Hi all, >> >> >> Now I found a bug of the filter. >> >> My ParaView's version is 3.14.1. >> I define node names as below: >> > c--d >> > | | >> > a--b >> >> Case 1: a=1.0, b=0.0, c=0.0, d=0.0 >> Integration Value = 0.33333 >> >> Case 2: a=0.0, b=1.0, c=0.0, d=0.0 >> Integration Value = 0.16666 >> >> Case 3: a=0.0, b=0.0, c=1.0, d=0.0 >> Integration Value = 0.16666 >> >> Case 4: a=0.0, b=0.0, c=0.0, d=1.0 >> Integration Value = 0.33333 >> >> So Integration Values are calculated as (2*a+b+c+2*d)/6. >> I think it's not a good result. >> >> >> Magician >> >> >> On 2012/06/08, at 12:54, Magician wrote: >> >> > Hi all, >> > >> > >> > I'm now comparing integration results of each postprocessors. >> > I made a simple Quadratic VTK model as below: >> >> # vtk DataFile Version 2.0 >> > >> >> QuadCell >> >> ASCII >> >> DATASET UNSTRUCTURED_GRID >> >> POINTS 4 FLOAT >> >> 0 0 0 >> >> 1 0 0 >> >> 0 1 0 >> >> 1 1 0 >> >> CELLS 1 5 >> >> 4 0 1 3 2 >> >> CELL_TYPES 1 >> >> 9 >> >> POINT_DATA 4 >> >> SCALARS scalar FLOAT 1 >> >> LOOKUP_TABLE DEFAULT >> >> 0.0 >> >> 1.0 >> >> 2.0 >> >> 4.0 >> > >> > When I apply Point Data to Cell Data filter, >> > scalar values are interpolated as 1.75. >> > It may be calculated as (0.0+1.0+2.0+4.0)/4.0. >> > >> > But when I apply Integrate Variables filter, >> > scalar value is integrated as 1.833.... >> > The area value of quadratic cell is 1.0, so I thought >> > integrated values should be equal to cell data. >> > >> > How the integrated value is calculated? >> > >> > >> > Magician >> >> _______________________________________________ >> Powered by www.kitware.com >> >> Visit other Kitware open-source projects at >> http://www.kitware.com/opensource/opensource.html >> >> Please keep messages on-topic and check the ParaView Wiki at: >> http://paraview.org/Wiki/ParaView >> >> Follow this link to subscribe/unsubscribe: >> http://www.paraview.org/mailman/listinfo/paraview >> > > > > _______________________________________________ > Powered by www.kitware.com > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Please keep messages on-topic and check the ParaView Wiki at: > http://paraview.org/Wiki/ParaView > > Follow this link to > subscribe/unsubscribe:http://www.paraview.org/mailman/listinfo/paraview > >
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