<div>I will check it.</div>
<div> </div>
<div>Thanks.</div>
<div> </div>
<div>-Zhanping<br><br></div>
<div class="gmail_quote">On Sat, Apr 11, 2009 at 12:15 AM, Takuya OSHIMA <span dir="ltr"><<a href="mailto:oshima@eng.niigata-u.ac.jp">oshima@eng.niigata-u.ac.jp</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Hi Jie, Renato,<br><br>There had been a bug until ParaView 3.4 that led the volume of a wedge<br>to have been miscalculated as a negated volume of a tetrahedron.<br>
<a href="http://www.paraview.org/pipermail/paraview/2008-August/009246.html" target="_blank">http://www.paraview.org/pipermail/paraview/2008-August/009246.html</a><br><a href="http://paraview.org/Bug/view.php?id=7588" target="_blank">http://paraview.org/Bug/view.php?id=7588</a><br>
<br>The bug has been fixed with the recent CVS versions.<br><br>I can confirm that the bug also affects volume calculations of clipped<br>hexahedral meshes as well by Jie's test.vtk. If I try the .vtk with a<br>CVS version and follow Jie's procedure I get a volume of 4.95177e-13<br>
which is closer to the analytic value of 5.23599e-13. However if I<br>revert the bugfix (revert vtkWedge.cxx from the current revision 1.7<br>to ParaView 3.4's 1.5) I get the identical value with what Jie got,<br>3.32862e-13.<br>
<br>Takuya OSHIMA, Ph.D.<br>Faculty of Engineering, Niigata University<br>8050 Ikarashi-Ninocho, Nishi-ku, Niigata, 950-2181, JAPAN<br><br><br>From: Renato Elias <<a href="mailto:rnelias@gmail.com">rnelias@gmail.com</a>><br>
Subject: Re: [Paraview] Questions regarding: volume calculation, xyplot along a curve and tensor calculation<br>Date: Fri, 10 Apr 2009 22:39:36 -0300<br><br>> It seems rounding errors... try to scale your model at least 100x to see<br>
> what happens...<br>><br>> Just to reforce Jie Xu's problem. It's not the first time the Integrate<br>> Variable presents issues in volume calculations. Take a look:<br>> <a href="http://markmail.org/message/67dkxpypfodylfnr#query:volume%20integration%20paraview%20renato+page:1+mid:67dkxpypfodylfnr+state:results" target="_blank">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>><br>> Renato.<br>><br>><br>
><br>> On Fri, Apr 10, 2009 at 4:30 PM, Jie Xu <<a href="mailto:victoryxj@gmail.com">victoryxj@gmail.com</a>> wrote:<br>><br>>> 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>>> Jie<br>>><br>>> On Thu, Apr 9, 2009 at 1:51 PM, Berk Geveci <<a href="mailto:berk.geveci@kitware.com">berk.geveci@kitware.com</a>><br>>> 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>Powered by <a href="http://www.kitware.com/" target="_blank">www.kitware.com</a><br><br>Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>
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</blockquote></div><br><br clear="all"><br>-- <br>Zhanping Liu, PhD<br>Kitware, Inc.<br>28 Corporate Drive<br>Clifton Park, NY 12065-8662<br>Phone: 518-371-3971 x 138<br><a href="http://www.zhanpingliu.org">http://www.zhanpingliu.org</a><br>