It seems rounding errors... try to scale your model at least 100x to see what happens...<br><br>Just to reforce Jie Xu's problem. It's not the first time the Integrate Variable presents issues in volume calculations. Take a look: <a href="http://markmail.org/message/67dkxpypfodylfnr#query:volume%20integration%20paraview%20renato+page:1+mid:67dkxpypfodylfnr+state:results">http://markmail.org/message/67dkxpypfodylfnr#query:volume%20integration%20paraview%20renato+page:1+mid:67dkxpypfodylfnr+state:results</a> <br>
<br>In my case, I don't remember if the problem was solved....<br><br>I tried to find my dataset to test it again but I haven't found (yet).... :-(<br><br>Renato.<br><br><br><br><div class="gmail_quote">On Fri, Apr 10, 2009 at 4:30 PM, Jie Xu <span dir="ltr"><<a href="mailto:victoryxj@gmail.com">victoryxj@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi Berk,<br>
<br>
Thanks for looking at my questions.<br>
<br>
1) I attached a sample data set: test.vtk, and the screenshot of my<br>
paraview window, from which you can see that the clip is created at<br>
(0,0,0) with radius of 50e-6, and the calculated volume is<br>
3.32862e-13, which is much less than what it should be.<br>
(Interestingly, in this specific case, the calculated volume is about<br>
2/pi times the real volume.)<br>
<br>
2) Thanks for letting me know.<br>
<br>
3) Unfortunately, I have no experience with Python. Now I am trying to<br>
see if I can use matlab to do the tensor calculates and modify the vtk<br>
file readable by paraview.<br>
<br>
Regards,<br>
<font color="#888888">Jie<br>
</font><div><div></div><div class="h5"><br>
On Thu, Apr 9, 2009 at 1:51 PM, Berk Geveci <<a href="mailto:berk.geveci@kitware.com">berk.geveci@kitware.com</a>> wrote:<br>
> Hi Jie,<br>
><br>
>> 1) Volume calculation:<br>
>> I found that the "integrate variables" over a sphere clip never gives<br>
>> the correct volume. For example, I tried to use a very simple geometry<br>
>> and a very fine mesh (a 200x200x200 micron cube with 2 micron cube<br>
>> elements), and use paraview to generate a sphere clip that has radius<br>
>> of 50 micron in the center of that cube, then I apply the "integrate<br>
>> variables" filter to the clip and show the "Cell Data", it gives a<br>
>> volume of 4.78818e-13 instead of 5.236e-13, which is 4/3*pi*r^3. The<br>
>> discrepancy is so large that it just cannot be due to the coarseness<br>
>> of the mesh. Different mesh and different size of clips gives<br>
>> different discrepancies, and I cannot find any obvious relationship<br>
>> between the paraview-calculated volume and the real volume.<br>
><br>
> When I create a 100^3 wavelet and clip it with a sphere of radius 20,<br>
> I am getting a volume of 33447.5 which is pretty close to the analytic<br>
> value of 33510.3. Can you send me a dataset that demonstrates this<br>
> problem?<br>
><br>
>> 2) X-Y plot: how can I do a xyplot of a scalar along a curved line?<br>
>> For example, if I have the pressure field data from a<br>
>> flow-around-a-cylinder case, I want to plot the pressure along the<br>
>> surface of the cylinder as a function of angle or arc length.<br>
><br>
> You can't, yet. I am working on that feature for the next release.<br>
><br>
>> 3) tensor calculation: I have the pressure field and velocity field<br>
>> calculated from a CFD tool (Transat in my case), how do I calculate<br>
>> stress tensors at each point from P V field in paraview?<br>
><br>
> Let me ask a question back : do you have any Python knowledge? We are<br>
> working on making this really simple but currently the array<br>
> calculator is too limited and cannot produce tensors. However, this is<br>
> doable using the programmable filter.<br>
><br>
> -berk<br>
><br>
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