[vtkusers] get points of a cutter

[KS Jothybasu]

I am bale to get the points like this

cutter=vtk.vtkCutter()
        cutter.SetCutFunction(plane)
        cutter.SetInput(vtkObject.GetOutput())
        cutter.Update()

        out=cutter.GetOutput()
        points=out.GetPoints()
        NumPts=points.GetNumberOfPoints()
        #print NumPts
        OutlinePts=np.zeros([NumPts,3])
        for n in range(0,NumPts,1):
            OutlinePts[n,:]=np.round(points.GetPoint(n))


As David said, you have to call the Update method.

Jothy

On Thu, Feb 4, 2010 at 7:04 PM, David Doria
<daviddoria+vtk at gmail.com<daviddoria%2Bvtk at gmail.com>
> wrote:

>
>
> On Thu, Feb 4, 2010 at 11:46 AM, Eddy Cappeau <ecappeau at phenix-systems.com
> > wrote:
>
>> Hi,
>>
>> I'm new to VTK and I'v got a little problem with it.
>> I want to cut a mesh with a plane and get the polyline of the
>> intersection.
>> The mesh come from a stl file loaded like this :
>>
>>    vtkSmartPointer<vtkSTLReader> reader =
>> vtkSmartPointer<vtkSTLReader>::New();
>>    reader->SetFileName("myfile.stl");
>>
>>    vtkSmartPointer<vtkPolyDataMapper> stlMapper =
>> vtkSmartPointer<vtkPolyDataMapper>::New();
>>    stlMapper->SetInputConnection(reader->GetOutputPort());
>>
>> I create a cutter like this :
>>
>>    vtkCutter * sliceCutter = vtkCutter::New();
>>    sliceCutter->SetInput( reader->GetOutput() );
>>    vtkPlane *slicePlane = vtkPlane::New();
>>    slicePlane->SetOrigin(0.0,0.0,7.0);
>>    slicePlane->SetNormal(0.0,0.0,1.0);
>>
>>    sliceCutter->SetCutFunction( slicePlane );
>>
>> I'v created a mapper and an actor for the mesh and the section, and i can
>> visualize them both.
>>
>> So I try to retrieve the points like this :
>>
>>    vtkPolyData * testdata = sliceCutter->GetOutput();
>>    vtkPoints * points = sliceCutter->GetOutput()->GetPoints();
>>    int n = points->GetNumberOfPoints();
>>
>> But the vtkPoints is always NULL and  I don't understand why.
>> How can I get those points ?
>>
>> thanks.
>> _____
>
>
> Sounds like you need to call Update on the cutter
> sliceCutter->Update();
>
> Let me know if that works.
>
> Thanks,
>
> David
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20100205/f9c8a11c/attachment.htm>