<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Hi!</div><div><br class="webkit-block-placeholder"></div><div>We have developed a vtkUnstructuredGridQuadricDecimation filter that simplifies 3-D unstructured grids. It implements a non-streamable version of the algorithm described in "Streaming Simplification for Tetrahedral Meshes Grids", H. Vo, S. Callahan, P. Lindstrom, V. Pascucci, and C. Silva, IEEE Transactions on Visualization and Computer Graphics, 13(1):145-155, 2007.</div><div><br class="webkit-block-placeholder"></div><div>We would be happy to contribute this code to VTK, if people find it useful. We have been using it "in house" at Utah for 2 years now, and it has been quite stable.</div><div><br class="webkit-block-placeholder"></div><div>In the meantime, I can simply send a copy to whoever wants it. Please let me know.</div><div><br class="webkit-block-placeholder"></div><div>Claudio.</div><div><br class="webkit-block-placeholder"></div><div><br class="webkit-block-placeholder"></div><br><div><div>On Nov 14, 2007, at 12:23 AM, Sylvester Gerardson wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> <div> <div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="281372207-14112007">Randall and Simone,</span></font></div> <div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="281372207-14112007"></span></font> </div> <div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="281372207-14112007">Thank you both for your help. Too bad it can't be done though...</span></font></div> <div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="281372207-14112007"></span></font> </div> <div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="281372207-14112007">Sylvester</span></font></div><br> <div class="OutlookMessageHeader" lang="nl" dir="ltr" align="left"> <hr tabindex="-1"> <font face="Tahoma" size="2"><b>From:</b> Randall Hand [<a href="mailto:randall.hand@gmail.com">mailto:randall.hand@gmail.com</a>] <br><b>Sent:</b> Wednesday, November 14, 2007 3:23 AM<br><b>To:</b> Simone Crippa<br><b>Cc:</b> Sylvester Gerardson; <a href="mailto:paraview@paraview.org">paraview@paraview.org</a><br><b>Subject:</b> Re: [Paraview] Quadric Clustering on 3D Unstructured Grid (PV3.2)<br></font><br></div> <div></div>Quadric Clustering only applies to Polygonal datasets. Volumetric Datasets cannot be decimated via the Quadric Clustering algorithm. Using the Extract Surface simply extracts a polygonal outer surface from your volume which is why you're then able to use it. <br><br><br> <div class="gmail_quote">On Nov 13, 2007 8:10 AM, Simone Crippa <<a href="mailto:crippa@kth.se">crippa@kth.se</a>> wrote:<br> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">Hi,<br><br>OK, sorry I misread your post ... I obviously thought that you want to<br>apply quadric clustering on a boundary grid.<br>I hope somebody else can help you out on how to do it for a volume<br>dataset, as I also didn't manage so far with it! <br> <div> <div></div> <div class="Wj3C7c"><br><br>/Simone<br><br><br><br>Sylvester Gerardson wrote:<br>> Hi Simone,<br>><br>> Thank you for your answer.<br>><br>> I am not sure I understand your suggestion. When I apply the 'Extract <br>> Surface' filter only my (3D) surfaces remain and the Quadric<br>> Clustering filter becomes available.<br>><br>> But I need the volume cells, not the surfaces. Am I doing something wrong?<br>><br>> regards,<br>> Sylvester<br>><br>><br>> On 11/13/07, Simone Crippa <<a href="mailto:crippa@kth.se">crippa@kth.se</a>> wrote:<br>>> Hi,<br>>><br>>> the way I do it is to extract first the surface of the unstructured grid <br>>> (vtkDataSetSurfaceFilter), then it is possible to use quadric clustering.<br>>><br>>><br>>> /Simone<br>>><br>>><br>>><br>>><br>>> Sylvester Gerardson wrote:<br>>>> Hi All,<br>>>><br>>>> How do I apply the Quadric Clustering filter to a 3D Unstructured Grid? (it<br>>>> is greyed out in the menu) Or is there another way to coarsen the mesh?<br>>>> I've used it with great success on 2D cutplanes. <br>>>><br>>>> A bit of coding and compiling is not a problem for me.<br>>>><br>>>> Thank you.<br>>>><br>>>> Sylvester<br>>>><br>>>> _______________________________________________ <br>>>> ParaView mailing list<br>>>> <a href="mailto:ParaView@paraview.org">ParaView@paraview.org</a><br>>>> <a href="http://www.paraview.org/mailman/listinfo/paraview" target="_blank">http://www.paraview.org/mailman/listinfo/paraview </a><br>>><br>>> --<br>>> Simone Crippa<br>>> Research assistant, Dipl.-Ing.<br>>> Royal Institute of Technology (KTH)<br>>> Aeronautical and Vehicle Engineering<br>>> Division of Aerodynamics <br>>> Teknikringen 8<br>>> SE-10044 Stockholm, Sweden<br>>> +46 (0)8 790 6465<br>>><br><br><br></div></div>--<br> <div> <div></div> <div class="Wj3C7c">Simone Crippa<br>Research assistant, Dipl.-Ing. <br>Royal Institute of Technology (KTH)<br>Aeronautical and Vehicle Engineering<br>Division of Aerodynamics<br>Teknikringen 8<br>SE-10044 Stockholm, Sweden<br>+46 (0)8 790 6465<br>_______________________________________________ <br>ParaView mailing list<br><a href="mailto:ParaView@paraview.org">ParaView@paraview.org</a><br><a href="http://www.paraview.org/mailman/listinfo/paraview" target="_blank">http://www.paraview.org/mailman/listinfo/paraview </a><br></div></div></blockquote></div><br><br clear="all"><br>-- <br>----------------------------------------<br>Randall Hand <br>Visualization Scientist<br>ERDC MSRC-ITL </div> _______________________________________________<br>ParaView mailing list<br><a href="mailto:ParaView@paraview.org">ParaView@paraview.org</a><br>http://www.paraview.org/mailman/listinfo/paraview<br></blockquote></div><br></body></html>