<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Hi Andrew and Dan,<div><br></div><div>Thanks very much for your help and the useful Python script.</div><div><br></div><div>I have now fixed the problem, it was related to a bug in the way I generate my vtkPolyData objects from my input data. </div><div><br></div><div>For future reference, my input data consists of a set of closed loops consisting of 3D points, stored in a vector<vector<double>>.</div><div>I now successfully convert this to vtkPolyData using the following two functions:</div><div><br></div><div><div>vtkSmartPointer<vtkPolyData> convertContourToPolyData(vector<double> c) {</div><div> auto points = vtkSmartPointer<vtkPoints>::New();</div><div> for (auto i = 0; i < c.size(); i += 3) {</div><div> auto id = points->InsertNextPoint(c[i], c[i + 1], c[i + 2]);</div><div> }</div><div><br></div><div> auto poly_line = vtkSmartPointer<vtkPolyLine>::New();</div><div> poly_line->GetPointIds()->SetNumberOfIds(points->GetNumberOfPoints());</div><div> for (auto i = 0; i < points->GetNumberOfPoints(); i++) {</div><div> poly_line->GetPointIds()->SetId(i, i);</div><div> }</div><div><br></div><div> auto cells = vtkSmartPointer<vtkCellArray>::New();</div><div> cells->InsertNextCell(poly_line);</div><div><br></div><div> auto poly_data = vtkSmartPointer<vtkPolyData>::New();</div><div> poly_data->SetPoints(points);</div><div> poly_data->SetLines(cells);</div><div><br></div><div> return poly_data;</div><div>}</div></div><div><br></div><div><div>vtkSmartPointer<vtkPolyData> convertContoursToPolyData(vector<vector<double>> contours) {</div><div> auto append_filter = vtkSmartPointer<vtkAppendPolyData>::New();</div><div><br></div><div> for (auto c : contours) {</div><div> append_filter->AddInputData(convertContourToPolyData(c));</div><div> }</div><div> append_filter->Update();</div><div><br></div><div> return append_filter->GetOutput();</div></div><div>}</div><div><br></div><div>Kind regards,</div><div><br></div><div>Dave</div><div><br><div><div>On 26 May 2016, at 03:12, Andrew Maclean <<a href="mailto:andrew.amaclean@gmail.com">andrew.amaclean@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div>Hi David and Dan,</div><div><br></div>I had a little look at the data using Dan's python script.<div><br></div><div>Line 29 needs to be changed from:</div><div>points.InsertPoint(currentPointId, d.GetPoint(pointIds[i]))</div><div>to:</div><div>points.InsertPoint(currentPointId, d.GetPoint(i))<br></div><div><br></div><div>When this is done, out.vtp has the points that are not associated with the cells in the original data in it.</div><div><br></div><div>Now, if you change line 28 to:</div><div>if pointIds[i] == 1 and i > 0:<br></div><div>This will select all points associated with the cells. The extra i > 0 condition is needed as point 0 in cell 0 lies way outside the boundary of all the other points for some reason, yet is associated with a cell. This one point has a value of: (0, 3.6e19, -5.2e27), whilst the dimensions of the polygonal mesh are:<br></div><div>X-range: -195 to 193 (delta: 389)</div><div>Y-range: -45.2 to 242 (delta: 287)</div><div>Z-range: -583 to 362 (delta: 945)</div><div><br></div><div>This is a nice little script Dan for filtering out points not associated with cells, I'll add it to my list of useful scripts, thanks.</div><div><br></div><div><br></div><div>Regards</div><div> Andrew</div><div><br><div class="gmail_extra"><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><br><br>---------- Forwarded message ----------<br>From: David Edmunds <<a href="mailto:David.Edmunds@icr.ac.uk">David.Edmunds@icr.ac.uk</a>><br>To: Dan Lipsa <<a href="mailto:dan.lipsa@kitware.com">dan.lipsa@kitware.com</a>><br>Cc: "<a href="mailto:vtkusers@vtk.org">vtkusers@vtk.org</a>" <<a href="mailto:vtkusers@vtk.org">vtkusers@vtk.org</a>>, David Edmunds <<a href="mailto:David.Edmunds@icr.ac.uk">David.Edmunds@icr.ac.uk</a>><br>Date: Wed, 25 May 2016 14:51:14 +0100<br>Subject: Re: [vtkusers] Traversing vtkPolyData returns incorrect number of points<br><div style="word-wrap:break-word">Hi,<div><br></div><div>Sorry for the late reply but I couldn’t send attachments to the mailing list. My input file can be found at <a href="http://www.filedropper.com/organbody" target="_blank">http://www.filedropper.com/organbody</a>.</div><div><br></div><div>Kind regards,</div><div><br></div><div>Dave</div><div><br><div><div>On 23 May 2016, at 18:20, Dan Lipsa <<a href="mailto:dan.lipsa@kitware.com" target="_blank">dan.lipsa@kitware.com</a>> wrote:</div><br><blockquote type="cite"><div dir="ltr">I see,<div>Well, in this case, you may have points that are not part of any cells. Can you share your data file?</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 23, 2016 at 12:16 PM, David Edmunds <span dir="ltr"><<a href="mailto:David.Edmunds@icr.ac.uk" target="_blank">David.Edmunds@icr.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div style="word-wrap:break-word">Hi Dan,<div><br></div><div>Thanks, but I actually get a much smaller number when I count all the points from cells. Also, in my input dataset the cells are disjoint, i.e. no points are shared between multiple cells.</div><div><br></div><div>Kind regards,</div><div><br></div><div>Dave</div><div><div><br></div><div><div><div>On 23 May 2016, at 16:51, Dan Lipsa <<a href="mailto:dan.lipsa@kitware.com" target="_blank">dan.lipsa@kitware.com</a>> wrote:</div><br><blockquote type="cite"><div dir="ltr">Hi David,<div>You have shared points between cells so it is normal you'll get a bigger number when you count all the points from cells.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 23, 2016 at 10:01 AM, David Edmunds <span dir="ltr"><<a href="mailto:David.Edmunds@icr.ac.uk" target="_blank">David.Edmunds@icr.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">Dear all,<br>
<br>
I am traversing a vtkPolyData object which is read in from a file using vtkXMLPolyDataReader. I access the number of points in the vtkPolyData in two different ways, here is my source code:<br>
<br>
vtkSmartPointer<vtkXMLPolyDataReader> reader = vtkSmartPointer<vtkXMLPolyDataReader>::New();<br>
reader->SetFileName("/Users/dedmunds/Desktop/organ_Body.vtp");<br>
reader->Update();<br>
vtkSmartPointer<vtkPolyData> poly_data = reader->GetOutput();<br>
<br>
cout << "Number of points: " << poly_data->GetNumberOfPoints() << endl;<br>
<br>
int traversal_points = 0;<br>
for (int i=0; i<poly_data->GetNumberOfCells(); i++) {<br>
traversal_points += poly_data->GetCell(i)->GetNumberOfPoints();<br>
}<br>
cout << "Traversal number of points: " << traversal_points << endl;<br>
<br>
Here is the output:<br>
<br>
Number of points: 286402<br>
Traversal number of points: 143204<br>
<br>
Why do I get two different answers? The second number is approximately half the first. What am I doing wrong?<br>
<br>
Thanks for your help,<br>
<br>
Kind regards,<br>
<br>
Dave<br>
<br>
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The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP.<br>
<br>
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The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP.<br>
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