Hi, Sam, <div> Would you mind reposting this? The pdf file seems corrupt.</div><div>thanks,</div><div>Leo<br><br><div class="gmail_quote">On Sun, Jun 10, 2012 at 7:38 PM, Samuel Key <span dir="ltr"><<a href="mailto:samuelkey@bresnan.net" target="_blank">samuelkey@bresnan.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Hi Leo,<br>
<br>
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.<br>
<br>
If it helps, please free to incorporate it into ParaView.<br>
<br>
Sam Key.<div><div class="h5"><br>
<br>
<br>
<br>
On 6/10/2012 12:55 PM, Yuanxin Liu wrote:
<blockquote type="cite">Hi, <br>
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.
<div>
<br>
</div>
<div>Leo</div>
<div><br>
</div>
<br>
<div class="gmail_quote">On Sat, Jun 9, 2012 at 8:57 AM, Magician
<span dir="ltr"><<a href="mailto:f_magician@mac.com" target="_blank">f_magician@mac.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi all,<br>
<br>
<br>
Now I found a bug of the filter.<br>
<br>
My ParaView's version is 3.14.1.<br>
I define node names as below:<br>
> c--d<br>
> | |<br>
> a--b<br>
<br>
Case 1: a=1.0, b=0.0, c=0.0, d=0.0<br>
Integration Value = 0.33333<br>
<br>
Case 2: a=0.0, b=1.0, c=0.0, d=0.0<br>
Integration Value = 0.16666<br>
<br>
Case 3: a=0.0, b=0.0, c=1.0, d=0.0<br>
Integration Value = 0.16666<br>
<br>
Case 4: a=0.0, b=0.0, c=0.0, d=1.0<br>
Integration Value = 0.33333<br>
<br>
So Integration Values are calculated as (2*a+b+c+2*d)/6.<br>
I think it's not a good result.<br>
<span><font color="#888888"><br>
<br>
Magician<br>
</font></span>
<div>
<div><br>
<br>
On 2012/06/08, at 12:54, Magician wrote:<br>
<br>
> Hi all,<br>
><br>
><br>
> I'm now comparing integration results of each
postprocessors.<br>
> I made a simple Quadratic VTK model as below:<br>
>> # vtk DataFile Version 2.0<br>
><br>
>> QuadCell<br>
>> ASCII<br>
>> DATASET UNSTRUCTURED_GRID<br>
>> POINTS 4 FLOAT<br>
>> 0 0 0<br>
>> 1 0 0<br>
>> 0 1 0<br>
>> 1 1 0<br>
>> CELLS 1 5<br>
>> 4 0 1 3 2<br>
>> CELL_TYPES 1<br>
>> 9<br>
>> POINT_DATA 4<br>
>> SCALARS scalar FLOAT 1<br>
>> LOOKUP_TABLE DEFAULT<br>
>> 0.0<br>
>> 1.0<br>
>> 2.0<br>
>> 4.0<br>
><br>
> When I apply Point Data to Cell Data filter,<br>
> scalar values are interpolated as 1.75.<br>
> It may be calculated as (0.0+1.0+2.0+4.0)/4.0.<br>
><br>
> But when I apply Integrate Variables filter,<br>
> scalar value is integrated as 1.833....<br>
> The area value of quadratic cell is 1.0, so I thought<br>
> integrated values should be equal to cell data.<br>
><br>
> How the integrated value is calculated?<br>
><br>
><br>
> Magician<br>
<br>
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