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<div>I might be mistaken, but I thought the triangulation filter correctly handled concave polygons. The advice I usually see on the ParaView mailing list when someone's concave polygons are not rendering correctly is to triangulate them.</div>
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<div>-Ken</div>
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<span style="font-weight:bold">From: </span>Philippe Pébay <<a href="mailto:philippe.pebay@kitware.com">philippe.pebay@kitware.com</a>><br>
<span style="font-weight:bold">Date: </span>Tuesday, March 12, 2013 9:53 AM<br>
<span style="font-weight:bold">To: </span>David Thompson <<a href="mailto:david.thompson@kitware.com">david.thompson@kitware.com</a>><br>
<span style="font-weight:bold">Cc: </span>VTK Developers <<a href="mailto:vtk-developers@vtk.org">vtk-developers@vtk.org</a>><br>
<span style="font-weight:bold">Subject: </span>[EXTERNAL] Re: [vtk-developers] Measuring the area of arbitrary polygons<br>
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<div>Hello D<br>
<br>
Thanks for the prompt answer. So this is what I was concerned about :) Namely that there is no way to generically deal with concave polygons at this point. In fact, just finding a correct triangulation is not trivial. One could for instance compute a CDT and
remove outside triangles. This would be computationally expensive for large meshes composed of such elements, but is there another choice?<br>
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Thanks<br>
P<br>
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<div class="gmail_quote">On Tue, Mar 12, 2013 at 3:31 PM, David Thompson <span dir="ltr">
<<a href="mailto:david.thompson@kitware.com" target="_blank">david.thompson@kitware.com</a>></span> wrote:<br>
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Hi P,<br>
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> Is anyone aware of a routine already available to measure the surface area of arbitrary planar polygons in VTK, including non-convex ones?<br>
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I don't know of anything in VTK to handle concave polygons. For convex ones, I believe the triangulate filter followed by the mesh quality filter should get you the area of a decomposition of the polygon. Assuming that the triangulate filter creates pedigree
IDs, you could sum areas with matching pedigree IDs.<br>
<span class="HOEnZb"><font color="#888888"><br>
David</font></span></blockquote>
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-- <br>
<font color="#888888">Philippe Pébay, PhD<br>
</font><font color="#888888">Director of Visualization and High Performance Computing /<br>
</font><font color="#888888">Directeur de la Visualisation et du Calcul Haute Performance<br>
Kitware SAS<br>
26 rue Louis Guérin, 69100 Villeurbanne, France</font><br>
<font color="#888888"><a value="+33426685003">+33 (0) 6.83.61.55.70 / 4.37.45.04.15</a></font><font color="#888888"><br>
<a href="http://www.kitware.fr/" target="_blank">http://www.kitware.fr</a></font><font color="#888888"><a href="http://www.kitware.fr/" target="_blank"></a></font></div>
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