[vtkusers] simple question vtkCleanPolyData

[Amy Squillacote]

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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