[vtkusers] vtkExtractEdges changes point IDs?

[Burnie West]

On 04/09/2010 11:07 AM, David Doria wrote:
>> Yes.  Here is what happens.  The "for" loops in the filter traverse
>> the geometry, i.e. the cells.  Whenever an input point is needed for
>> the output geometry, it is inserted into the output points.  As a
>> result, the sorting of the output points is different from the input
>> points.
>>
>> Conversely, for filters that traverse the points (as opposed to
>> traversing the cells), the output points are usually kept in the same
>> order as the input points.
>>
>>    David
>>
>>      
> Ah, makes sense. Thanks for the explanation.
>    
The word "usually" troubles me. In what cases might I expect the output 
points to be ordered differently from the input points for a filter that 
traverses the points?

  -- Burnie