[vtkusers] Filter to merge several lines into a single polyline?

[Jean-Dominique Barnichon]

Mathieu,

replacing
	LinePoly->SetLines((cutStrips->GetOutput())->GetLines());
by
	LinePoly->SetPolys(cutStrips->GetOutput()->GetLines());

doesn't do what I need : it build a closed polyline, which is not what I
expect as the 3D surface I am cutting through is not closed (it's a portion
of a digitized topographic map).
So in other word, I do expect an unclosed polyline as a result of the
cutting operation.

Jean-Do

-----Message d'origine-----
De : Mathieu Malaterre [mailto:mathieu.malaterre at kitware.com]
Envoye : mardi 11 mai 2004 22:46
A : Jean-Dominique Barnichon
Cc : vtkusers
Objet : Re: [vtkusers] Filter to merge several lines into a single
polyline?


Jean-Dominique,

	Change:

LinePoly->SetLines((cutStrips->GetOutput())->GetLines());

into

LinePoly->SetPolys(cutStrips->GetOutput()->GetLines());

HTH
Mathieu

Jean-Dominique Barnichon wrote:
> It's done already (see code of original message)
> Jean-Do
>
> -----Message d'origine-----
> De : Amy Henderson [mailto:amy.henderson at kitware.com]
> Envoye : mardi 11 mai 2004 22:09
> A : Jean-Dominique Barnichon; vtkusers
> Objet : Re: [vtkusers] Filter to merge several lines into a single
> polyline?
>
>
> Hi Jean-Do,
>
> Try passing the results of vtkCutter through vtkStripper.
>
> - Amy
>
> At 04:04 PM 5/11/2004, Jean-Dominique Barnichon wrote:
>
>>Hello,
>>
>>As a result of applying a vtkCutter filter to a 3D surface (see code
>
> snippet
>
>>below), I obtain a vtkPolyData object that is made of :
>> - a set of points,
>> - a set of lines (7 in the example below, see ouput below).
>>
>>You can notice that output lines share end points, i.e. they could
'easily'
>>all be converted into a single polyline (in the exmaple shown below, this
>>could be done starting backward from the last line, but I don't known this
>>can always be done this way).
>>
>>All I need is converting this set of 'jointive' lines into a single
>>polyline.
>>Is there any filter that can do that? Or do I have to write one by myself?
>>
>>Any answer/hint is welcome.
>>Note that applying vtkCleanPolyData is pointless here as there are already
>>no duplicate points.
>>
>>Jean-Do
>>
>>
>>code snippet
>>        //Define cutting plane
>>        vtkPlane* plane = vtkPlane::New();
>>        plane->SetOrigin(300., 500., 0);
>>        plane->SetNormal(-1, -1, 0);
>>
>>        //Generate cut lines
>>        vtkCutter* cutEdges = vtkCutter::New();
>>        cutEdges->SetInput(Normals->GetOutput());
>>        cutEdges->SetCutFunction(plane);
>>
>>        //Forms lines from cutter
>>        vtkStripper* cutStrips = vtkStripper::New();
>>        cutStrips->SetInput(cutEdges->GetOutput());
>>        cutStrips->Update();
>>
>>        //Defines polygons as polyline
>>        vtkPolyData* LinePoly = vtkPolyData::New();
>>        LinePoly->SetPoints((cutStrips->GetOutput())->GetPoints());
>>        LinePoly->SetLines((cutStrips->GetOutput())->GetLines());
>>
>>        //Write PolyData to file
>>        vtkPolyDataWriter* wr = vtkPolyDataWriter::New();
>>        wr->SetFileName("Line4.vtk");
>>        wr->SetInput(LinePoly);
>>        wr->Write();
>>
>>Output of the vtkPolyDataWriter (file Line4.vtk)
>># vtk DataFile Version 3.0
>>vtk output
>>ASCII
>>DATASET POLYDATA
>>POINTS 28 float
>>252.329 547.171 500 235.668 563.832 500 314.825 484.675 549.214
>>305.908 493.592 553.277 224.208 575.292 500 223.112 576.388 500
>>342.103 457.397 590.352 339.985 459.515 587.917 446.203 353.297 737.623
>>441.629 357.871 700 294.445 505.055 542.116 343.253 456.247 592.317
>>415.885 383.615 664.838 409.217 390.283 664.838 350.938 448.562 600
>>426.08 373.42 670.902 439.236 360.264 700 492.288 307.212 866.422
>>482.154 317.346 884.873 458.735 340.765 779.183 451.048 348.452 750.164
>>479.711 319.789 887.034 463.563 335.937 800 512.234 287.266 900
>>510.437 289.063 900 496.357 303.143 851.732 502.247 297.253 829.042
>>519.514 279.986 900
>>LINES 7 41
>>4 0 1 4 5
>>4 2 3 10 0
>>3 6 7 2
>>9 8 9 16 15 12 13 14 11 6
>>7 17 18 21 22 19 20 8
>>5 23 24 26 25 17
>>2 27 23
>>
>>CELL_DATA 7
>>POINT_DATA 28
>>
>>
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>
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