[vtkusers] simple question vtkCleanPolyData

[jeando.barnichon at free.fr]

Ok, I understand.
The next question now is :
Is there a filter that could do the "simple" task of "cleaning" (i.e. removing
duplicate points) a polydata that is made of points only?
Jean-Do

Selon Amy Squillacote <amy.squillacote at kitware.com>:

> You are right; you do need cells in your vtkPolyData, not just
> points.  This is because one of the features of vtkCleanPolyData is
> to remove points that are not used by any cells.  Thus if your data
> has no cells, then this is true for all the points in your data set,
> so all of them will be removed, resulting in an empty vtkPolyData data set.
>
> - Amy
>
> At 05:06 PM 4/17/2006, Janet Kim wrote:
> >I tried out vtkCleanPolyData and it looked like you
> >might need actual geometry for the polydata to clean,
> >not just points.  When I just had points, I had the
> >same result.  But once I added the points to cells,
> >the clean worked.  Maybe someone else can explain a
> >bit better, unless, I'm wrong.
> >
> >
> >On Mon, 17 Apr 2006, Jean-Dominique Barnichon wrote:
> >
> >>Should be a simple one.
> >>I've got a polydata containing only points (see end of email), some
> >>of which are duplicate points.
> >>I want to keep only a single point with given coordinates (yes, I
> >>know that the vtkCleanPolyData filter should do the trick, but I
> >>just can couldn't get it working so far).
> >>When I run the piece of code given below, the cleaned polydata is
> >>empty (i.e. it has 0 points), and I don't understand why.
> >>Any Idea?
> >>Jean-Do
> >>
> >>Code snippet:
> >>       vtkPolyDataReader *re = vtkPolyDataReader::New();
> >>       re->SetFileName("InitialPolydata.vtk");
> >>
> >>       vtkPolyData *pdata = vtkPolyData::New();
> >>       pdata = re->GetOutput();
> >>
> >>       // pdata is the vtkPolyData
> >>       vtkCleanPolyData *Clean = vtkCleanPolyData::New();
> >>       Clean->SetInput(pdata);
> >>       Clean->SetTolerance(0.0);
> >>       Clean->PointMergingOn();
> >>       Clean->Update();
> >>
> >>       vtkPolyDataWriter *wr = vtkPolyDataWriter::New();
> >>       wr->SetFileName("CleanedPolydata.vtk");
> >>       wr->SetInput(Clean->GetOutput());
> >>       wr->Write();
> >>
> >>
> >>//beginning_of_file (InitialPolydata.vtk)
> >># vtk DataFile Version 3.0
> >>vtk output
> >>ASCII
> >>DATASET POLYDATA
> >>POINTS 12 float
> >>3.35936 1.84257 49.9219 6.3551 1.84257 40.9347 17.8945 1.84257 39.9079
> >>17.8945 1.84257 39.9079 25.3551 1.84257 23.6583 25.3551 1.84257 23.6583
> >>34.0223 1.84257 20.6629 34.0223 1.84257 20.6629 36.8945 1.84257 20.1843
> >>45.263 1.84257 1.84257 45.263 1.84257 1.84257 83.3594 1.84257 0
> >>
> >>POINT_DATA 12
> >>//end_of_file
> >>
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