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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Dear VTK and ITK users,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I tried to calculate polydata volume through vtkMassProperties. Firstly, the polydata was generated from a set of 3D points. Then I applied vtkSurfaceReconstructionFilter to generate a surface. And then a contour was generated by vtkContourFilter. After several other steps, I got the volume by vtkMassProperties.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The problem is:<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Whether my code is proper to calculate polydata volume?<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>When I change the SetValue(0, 10) of vtkContourFilter to some value else, for example, SetValue(0, 20), the calculated volumes under the two conditions are very different. What value is proper to calculate volume?<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>What is the correct way to calculate polydata volume?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks very much! The following is the code:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe;color:blue'> for</span><span style='font-size:10.0pt;font-family:DotumChe'> (i = 0; i < spl_max; i++)<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> {<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> points->InsertNextPoint(segment_point_list[i][0], segment_point_list[i][1], segment_point_list[i][2]);<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:DotumChe'> }<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:DotumChe'> polydata->SetPoints(points);</span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkSurfaceReconstructionFilter *surf = vtkSurfaceReconstructionFilter::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> surf->SetInput(polydata); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkContourFilter *contours = vtkContourFilter::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> contours->SetInputConnection(surf->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> contours->SetValue(0,10); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:green'>// # Extract boundary edges <o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkFeatureEdges *boundary = vtkFeatureEdges::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> boundary->BoundaryEdgesOn(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> boundary->FeatureEdgesOff(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> boundary->ManifoldEdgesOff(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> boundary->NonManifoldEdgesOff(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> boundary->SetInputConnection(contours->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:green'>// # Build a polyline from boundary edges <o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkStripper *stripper = vtkStripper::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> stripper->SetInputConnection(boundary->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> stripper->Update(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkPolyData *holePoly = vtkPolyData::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> holePoly->SetPoints(stripper->GetOutput()->GetPoints()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> holePoly->SetPolys(stripper->GetOutput()->GetLines()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:green'>// # Triangulate hole <o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkTriangleFilter *filler = vtkTriangleFilter::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> filler->SetInput(holePoly); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:green'>// # Combine into a single polydata <o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkAppendPolyData *apd = vtkAppendPolyData::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> apd->AddInputConnection(contours->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> apd->AddInputConnection(filler->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:green'>// # Merge duplicate points <o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkCleanPolyData *cleaner = vtkCleanPolyData::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> cleaner->AddInputConnection(apd->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:green'>// # Add normals <o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkPolyDataNormals *apdNormals = vtkPolyDataNormals::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> apdNormals->SetInputConnection(cleaner->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkReverseSense *reverse = vtkReverseSense::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> reverse->SetInputConnection(apdNormals->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> reverse->ReverseCellsOn(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> reverse->ReverseNormalsOn(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkTriangleFilter *triangle = vtkTriangleFilter::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> triangle->SetInputConnection(reverse->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> vtkMassProperties *massProperty = vtkMassProperties::New(); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> massProperty->SetInputConnection(triangle->GetOutputPort()); <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;font-family:DotumChe'> massProperty->Update();<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:DotumChe'> <span style='color:blue'>double</span> vol = massProperty->GetVolume();</span><o:p></o:p></p></div></body></html>