[vtkusers] Error using SetOutput()

[David E DeMarle]

I'm not really familiar with pre 4.0 vtk to comment about a direct
translation, but could you use:

f1 -> vtkPassThrough -> g1/h1/j1 etc

?
Then when you want to swap f2 and f3 in, you can just change vtkPassThough's
input.

David E DeMarle
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x109


On Wed, Sep 16, 2009 at 3:11 PM, John Platt <jcplatt at dsl.pipex.com> wrote:

>  Hi Dave,
>
> This is the pipeline management problem I am trying to solve
>
>                                g1 -> g2 -> ...
> f1 -> [ f2 ] -> [ f3 ] ->  h1 -> h2 -> ...
>                                 j1 ->  j2 -> ...
>
> where the filters in [] are optional. I want to be able to add/remove f2 &
> f3 without having to find g1, h1 & j1 to reset the input connection. I
> therefore create the output object for the chain f1 -> [ f2 ] -> [ f3 ]  and
> use SetOutput() on the last filter. This way, the input connection to
> filters g1, h1 & j1 only has to be set once.
>
> This is a technique I used in VTK 4.2 with the 'old' pipeline
> architecture. Are there any other ways to achieve this effect?
>
> Thanks for help.
>
> John.
>
> ----- Original Message -----
>
>  *From:* David E DeMarle <dave.demarle at kitware.com>
> *To:* John Platt <jcplatt at dsl.pipex.com>
> *Cc:* vtkusers <vtkusers at vtk.org>
> *Sent:* Wednesday, September 16, 2009 6:34 PM
> *Subject:* Re: [vtkusers] Error using SetOutput()
>
> Are you sure you want to SetOutput? For the most part (that is everywhere
> other than within the filter which typically gets its own output from the
> executive and populates it) , filter outputs shouldn't be messed with for
> two reasons :
>
> * the next time the filter updates the output will be replaced
>
> * more than one thing can be connected to a given filter's output, so
> changing the output or its contents will cause inconsistency
>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 28 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-371-3971 x109
>
>
> On Tue, Sep 15, 2009 at 6:23 PM, John Platt <jcplatt at dsl.pipex.com> wrote:
>
>>  Hi,
>> I am having trouble moving an output between filters using SetOutput() as
>> follows.
>>
>> 1. Single filter, f1.
>>     vtkPolyData* myOutput = vtkPolyData::New();
>>      f1->SetOutput( myOutput );
>>
>>     vtkAppendPolyData* myAppend =  vtkAppendPolyData::New();
>>     myAppend->AddInput( myOutput );
>>
>> "myOutput" is displayed correctly.
>>
>> 2. Append filter f2 to f1.
>>     f1->SetOutput( 0 );
>>     f2->SetInputConnection( f1->GetOutputPort() );
>>     f2->SetOutput( myOutput );
>>
>> "myOutput" does not appear to see the changes made by filter f2.
>> 3. Remove filter f2.
>>     f 2->Delete();
>>     f1->SetOutput( myOutput );
>> ERROR: In
>> /home/john/VTK/vtk-5.4.2/VTK/Filtering/vtkStreamingDemandDrivenPipeline.cxx,
>> line 747
>> vtkStreamingDemandDrivenPipeline : No maximum number of pieces has been
>> set in the information for output port 0 on algorithm vtkf1"
>> Any help on using SetOutput() would be greatly appreciated.
>>
>> Thanks.
>>
>> John.
>>
>> _______________________________________________
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>>
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>  ------------------------------
>
> _______________________________________________
> 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
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