Retrieving point info from PolyData

[Jordi Cabot]

If you have used vtkPolyReader for example to read this file and you
have not rendered anything, you must call the Update method in order to
update the reader, and then use GetNumberOfPoints.


"Joy P. Ku" wrote:
> 
> When I call GetNumberOfPoints on a PolyData, created
> from the file below, I get a value of 0.  I was expecting
> to get a value of 32.  Can anyone tell me why I get a
> value of 0?
> 
> Joy Ku
> Stanford University
> 
> # vtk DataFile Version 2.0
> vtk output
> ASCII
> DATASET POLYDATA
> POINTS 32 float
> 43.2042 62.0422 20 42.7025 62.1283 20 43.9466 61.5733 20
> 43.5158 61.8454 20 44.4534 60.8563 20 44.1591 61.2726 20
> 44.6467 60 20 44.5345 60.4974 20 44.4982 59.1348 20
> 44.5845 59.6374 20 44.0293 58.3924 20 44.3016 58.8236 20
> 43.3122 57.8856 20 43.7284 58.1797 20 42.456 57.6923 20
> 42.9526 57.8044 20 41.5908 57.8408 20 42.0922 57.7547 20
> 40.8484 58.3097 20 41.2783 58.0382 20 40.3425 59.0268 20
> 40.6353 58.6118 20 40.1482 59.883 20 40.2606 59.3877 20
> 40.2978 60.7482 20 40.2113 60.2477 20 40.7657 61.4906 20
> 40.4949 61.061 20 41.4827 61.9974 20 41.0676 61.704 20
> 42.339 62.1908 20 41.8429 62.0787 20
> LINES 32 96
> 2 0 1
> 2 2 3
> 2 4 5
> 2 6 7
> 2 8 9
> 2 10 11
> 2 12 13
> 2 14 15
> 2 16 17
> 2 18 19
> 2 20 21
> 2 22 23
> 2 24 25
> 2 26 27
> 2 28 29
> 2 30 31
> 2 31 28
> 2 29 26
> 2 27 24
> 2 25 22
> 2 23 20
> 2 21 18
> 2 19 16
> 2 17 14
> 2 15 12
> 2 13 10
> 2 11 8
> 2 9 6
> 2 7 4
> 2 5 2
> 2 3 0
> 2 1 30
> 
> CELL_DATA 32
> SCALARS scalars float
> LOOKUP_TABLE default
> 0 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0 0
> 0 0 0 0 0
> POINT_DATA 32
> SCALARS scalars float
> LOOKUP_TABLE default
> 6.79584 7.29752 6.05339 6.48424 5.54658 5.84087 5.35326 5.46555 5.50182
> 5.41552 5.97068 5.69841 6.68776 6.27157 7.54404 7.04742 8.4092 7.90783
> 9.15165 8.72172 9.65746 9.36473 9.85178 9.73936 9.70222 9.78874 9.23435
> 9.50508 8.51727 8.93245 7.661 8.15713
> 
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