[vtkusers] generating isopoints with vtkContourFilter -- segmentation fault

[Greg Whittier]

I'm still having the problem of getting a segmentation fault when trying
to contour lines to get isopoints.  The previous example used VTKData. 
Below is a standalone version in both python and tcl that generates a
segmentation fault. I've verified that windows (python 2.2.3 enthought
edition) also generates a seg fault.

Can anyone confirm they get this behavior?  Am I doing something
obviously wrong?

Thanks,
Greg


## python version ##

import vtk
 
points = vtk.vtkPoints()
points.InsertPoint(0, 0.0, 0.0, 0.0)
points.InsertPoint(1, 1.0, 0.0, 0.0)
 
lines = vtk.vtkCellArray()
lines.InsertNextCell(2)
lines.InsertCellPoint(0)
lines.InsertCellPoint(1)
 
scalars = vtk.vtkFloatArray()
scalars.InsertNextValue(0.0)
scalars.InsertNextValue(1.0)
 
line = vtk.vtkPolyData()
line.SetLines(lines)
line.GetPointData().SetScalars(scalars)
 
cfilter = vtk.vtkContourFilter()
cfilter.SetValue(0,0.5)
cfilter.SetInput(line)
cfilter.Update()  # seg faults here

## tcl vesion ##
package require vtk
 
vtkPoints points
   points InsertPoint 0 0.0 0.0 0.0
   points InsertPoint 1 1.0 0.0 0.0
 
vtkCellArray lines
   lines InsertNextCell 2
   lines InsertCellPoint 0
   lines InsertCellPoint 1
 
vtkFloatArray scalars
   scalars InsertNextValue 0.0
   scalars InsertNextValue 1.0
 
vtkPolyData line
   line SetLines lines
   [line GetPointData] SetScalars scalars
 
vtkContourFilter cfilter
   cfilter SetValue 0 0.5
   cfilter SetInput line
   cfilter Update


On Sun, 2004-01-18 at 20:58, Greg Whittier wrote:
> I'm new to VTK, so I apologize if I'm doing something wrong here.  I
> would like to use vtkContourFilter with vtkPolyData to get a set of
> isopoints from a set of lines.  The vtkContourFilter docs say you can
> generate isopoints from 1D or 0D cell data, but I can't find any
> examples.  Is this really possible?  When I try, I get a segmentation
> fault.
> 
> Here is some sample code that generates a seg fault.
> 
> import vtk
>  
> reader = vtk.vtkPolyDataReader()
> reader.SetFileName("/usr/share/doc/vtk-data-4.5.0/Data/track1.binary.vtk")
> 
>  
> cfilter = vtk.vtkContourFilter()
> cfilter.SetValue(0,5.0)
> cfilter.SetInput(reader.GetOutput())
>  
> writer = vtk.vtkPolyDataWriter()
> writer.SetFileName('test.vtk')
> writer.SetInput(cfilter.GetOutput())
> writer.Write()
> 
> Opening track1.binary.vtk with mayavi and selecting isosurface also
> generates a seg fault.
> 
> I'm running Red Hat Linux 9 and using using the 20040118 rpms from
> http://creatis-www.insa-lyon.fr/vtk/.
> 
> Any help would be appreciated.  Thanks for such a great piece of
> software.
> 
> Greg
> 
> 
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-- 
Greg Whittier <greg at thewhittiers.com>