[vtkusers] Extract Polydata points with same scalar value

[Sara Rolfe]

Actually, I just realized that vtkThresholdPoints appears to have  
extracted the points and the connections were lost.  So when I run it  
though the vtkPolydataConnectivityFilter there is one region for each  
point in the polydata.  Could you let me know if there's a way to get  
vtkThresholdPoints to preserve connectivity, or if there's a better  
approach?

I've also tried using the vtkPolydaytaConnectivity filter operating on  
the scalar data, but was only able to get it to return the largest  
region for each label.

Thanks,
Sara


On Jun 26, 2012, at 2:16 PM, Sara Rolfe wrote:

> Hi Jochen,
>
> I was able to use vtkThresholdPoints to do exactly what I wanted.   
> Thanks for your help!
>
> Sara
>
> On Jun 26, 2012, at 1:52 AM, Jochen K. wrote:
>
>> Hi Sara,
>>
>> you may try to separate your polydata by scalar values using a  
>> vtkThresholdPoints object:
>>
>> untested snippet:
>>          //...
>>          vtkSmartPointer<vtkThresholdPoints> threshold =  
>> vtkSmartPointer<vtkThresholdPoints>::New();
>>          threshold.SetInput(contourPolydata);
>>          threshold.SetInputArrayToProcess(
>>             0,
>>             0,
>>             vtkDataObject::FIELD_ASSOCIATION_POINTS,
>>             vtkDataSetAttributes::SCALARS,
>>             "NameOfYourScalarArray");
>>          threshold->ThresholdBetween(0, 1); // would give you the  
>> points labeled with 1
>>          // you may have to experiment with the value range a bit
>>          //threshold->ThresholdBetween(1, 2); // would give you the  
>> points labeled with 2
>>
>>          threshold->Update();
>>
>>          vtkSmartPointer<vtkPolyData> part =  
>> vtkSmartPointer<vtkPolyData>::New();
>>          part->SetInputConnection(threshold->GetOutputConnection());
>>          //...
>>
>> best regards
>> Jochen
>> View this message in context: Re: Extract Polydata points with same  
>> scalar value
>> Sent from the VTK - Users mailing list archive at Nabble.com.
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