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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi Jothy<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Since you are using vtkDiscreteMarchingCubes, I assume your mesh is a 3d surface mesh.<o:p></o:p></p><p class=MsoNormal>vtkPolygon is meant to used for 2D polygons (e.g. a triangle in the xy-plane). Unless you project your 3D mesh to a 2d plane, and obtain the silhouette, this will not work.<o:p></o:p></p><p class=MsoNormal><a href="http://www.vtk.org/doc/nightly/html/classvtkPolyDataSilhouette.html">http://www.vtk.org/doc/nightly/html/classvtkPolyDataSilhouette.html</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Also, it seems dangerous or even wrong to cast the points and polygons to a double pointer like this. First, the points could also be floats. Second, I doubt the polys in your mesh can be cast to <double*>.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Instead, you should probably use one of the cell locators, e.g. vtkOBBTree or vtkCellLocator to test if your point is inside the mesh in 3D.<o:p></o:p></p><p class=MsoNormal>You could have a look at the code in “vtkSelectEnclosedPoints” to see how to do this in a robust way. You can even use this filter directly, via the function “vtkSelectEnclosedPoints::IsInsideSurface”.<o:p></o:p></p><p class=MsoNormal><a href="http://www.vtk.org/doc/nightly/html/classvtkSelectEnclosedPoints.html">http://www.vtk.org/doc/nightly/html/classvtkSelectEnclosedPoints.html</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers<o:p></o:p></p><p class=MsoNormal>Bryn<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> vtkusers-bounces@vtk.org [mailto:vtkusers-bounces@vtk.org] <b>On Behalf Of </b>Jothy<br><b>Sent:</b> Friday, July 22, 2011 4:39 PM<br><b>To:</b> VTK Mailing List<br><b>Subject:</b> [vtkusers] PointInPolygon returns 1 for all points within bounds<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hi all,<br><br>I have a mesh generated from vtkDiscreteMarchingCubes and processed through vtkDecimatePro and vtkWindowedSincPolyDataFilter. Now, I want to find the points/voxels inside this mesh. I am using vtkPolygon::PointInPolygon. But, the result is "1! for the all the points whichever falls with the bounds.<br><br>Here is the piece of code that I am using<br><br>(smoother is vtkWindowedSincPolyDataFilter)<br><br> int npts=smoother->GetOutput()-> GetPoints()->GetNumberOfPoints();// test point <br> //double n[3]={0.707, 0.707, 0};<br> double n[3];<br><br> vtkSmartPointer<vtkPolygon> polygon =<br> vtkSmartPointer<vtkPolygon>::New();<br> <b><span style='color:#CC0000'>polygon->ComputeNormal(mapper->GetInput()->GetPoints()->GetNumberOfPoints(),<br> static_cast<double*>(mapper->GetInput()->GetPoints()->GetData()->GetVoidPointer(0)), n); </span></b> <br><br> double bds[6];<br> smoother->GetOutput()->GetBounds(bds); <br> qDebug()<< polygon->PointInPolygon(testIn,npts,<b><span style='color:red'>static_cast<double*>(mapper->GetInput()->GetPolys()->GetData()->GetVoidPointer(0)</span></b>),bds,n)<<"Result";<br><br>Are these two highlighted lines correct?<br><br>Many thanks<br><br>Jothy<br> <o:p></o:p></p></div></div></body></html>