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="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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>>>> _______________________________________________
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</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>_______________________________________________
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</a><br></div></div></blockquote></div><br><br clear="all"><br>-- <br>----------------------------------------<br>Randall Hand <br>Visualization Scientist<br>ERDC MSRC-ITL