[Paraview] custom filter?

[Utkarsh Ayachit]

Custom filter mechanism is designed to be used to combine a sub-pipeline 
into a single filter (or source) (with all the a paramter settings for 
each of the individual filters/sources) exposing a subset of the 
parameters to the user.

Eg. Here's my pipeline:
Sphere -> Shrink --> "Extract Edges"

Suppose we want to combine the Shrink-->ExtractEdges into a new custom 
filter "ShrunkEdges".

* Select the Shrink and the Extract Edges filter in the pipeline browser 
(use Ctrl key for multiple selections).
* With the two filters selected, go to Tools menu and choose "Create 
Custom Filter"
* The "Create Custom Filter" wizard will show up.
* First give our filter a new name. This name must be unique and if 
conflicting an error message will be shown. We are calling this one 
"ShrunkEdges" (step1.png). Then click "Next".
* We now choose what are the inputs to the custom filter that the user 
can set. By default, paraView will find the first filter in the 
sub-pipeline (in this case "Shrink") and expose it's "Input" property as 
the input to this custom filter. Since that's exactly what we want here 
(step2.png), click "Next".
* Next we need to choose the outputs from this filter. By default, 
paraview will choose the last filter in the subpipeline (in this case 
'ExtractEdges'. Let's say we want this custom filter to have two 
outputs, the output after the shrink stage as well as the one after 
extracting edges. ExtractEdges is already exposed as an output, we now 
expose the shrink filter as well. Select the "Shrink" in the left-side 
tree. It's output ports will be shown the "Output Port" combo. Choose 
the output port (relevant if the filter itself had more than 1 output 
ports), the assign it some unique name, say "ShrunkOutput" then press 
"+" to add it to the exposed outputs list (step3.png).  Click "Next".
* Next we expose the subset of parameters on this custom filter that the 
user can change at run-time. Let's say we want to allow the user to 
change the "Shrink Factor" on the shrink filter. Select the "Shrink" 
filter in the tree and then select the property to expose in the 
"Property" combo, assign it some name (or use the default) and the hit 
"+" to expose it (step4.png). Once all required properties are exposed, 
click "Finish" to create a definition for the custom filter.

The "Custom Filter Manager" will popup showing the newly defined custom 
filter. The manager is also available under the "Tools" menu. It can be 
used to remove/export/import custom filters.

Close this dialog.

Now to instantiate our new custom filter, simply look under the 
"Filters|Alphabetical" menu, we see our new "ShrunkEdges" filter. Now 
you can create it simply as if it were a normal filter.

Same is true with sources, if no input property is exposed, it's treated 
as a source and is available under "Sources" menu.

Utkarsh






Dominik Szczerba wrote:
> I have a complicated layout of filters on the left panel. How do I go about 
> saving them as a filter in PV CVS? (saving state does not work for transient, 
> fixing number current time steps). I tried 'create a custom filter' but it is 
> not comprehensive. I clicked around and ended up nowhere. Any hints are 
> appreciated.
> PS. I dd not find anything on wiki, and can again no longer find a search link 
> to ML archives.
> 
> best regards
> 
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