[Paraview] Exposing Timesteps in a Custom File Format

[Berk Geveci]

Hi Mike,

First a disclaimer: the time support in VTK and ParaView is evolving.

Currently, the only way to set the time on a reader in ParaView is
though a set/get method pair on the public API. Exodus does this by
providing SetTimeStep and GetTimeStep methods. To add the time
support on the GUI, readers.xml and Readers.xml files have to updated.

In VTK, a time aware pipeline can send UPDATE_TIME_INDEX() to request
a specific time step instead of using the public methods. This is not
yet supported in paraview. It is however on our roadmap.

A reader tells the pipeline (and paraview) which time steps are
available by setting TIME_STEPS() key on the output information during
RequestInformation(). This is also what is used to automatically display
the current time value as annotation.

Also, there has been some recent changes to the time support in VTK.
UPDATE_TIME_INDEX() is no longer used. UPDATE_TIME_STEPS() is used
instead. This is not index based. It contains the time values that the
pipeline is requesting. It is up to the reader to find the closest time
step or even interpolate if desired. For more information, look here:
http://www.vtk.org/Wiki/VTK/Time_Support

I hope that there will be an article on this in the next Kitware Source.

-berk

On 11/8/06, Mike Jackson <mike.jackson at imts.us> wrote:
> I am developing a ParaView reader for my custom file format. Inside our
data
> we have the data laid by timesteps. I was wanting to use this information
> inside of ParaView so I am basically copying the Exodus Reader (at least
the
> timestep portion). So far everything is ok except that the following line
of
> code comes back false:
>
>   if(outInfo->Has(vtkStreamingDemandDrivenPipeline::UPDATE_TIME_INDEX()))
>
> It is with in this block that the time value and the index get updated but
> for some reason when run in my code this comes back false. I am currently
> running the reader using a command line "test" program and have not
actually
> tried it in ParaView for some other reasons. Is there a special type of
> pipeline I need to instantiate in a non-ParaView setting? Is there
something
> is the xml files that needs to be set so the UPDATE_TIME_INDEX key is
> present? How about in the header file for my class? Maybe some
undocumented
> accessor method?
>
> Any help would be appreciated.
>
> --
> Mike Jackson   Senior Research Engineer
> Innovative Management & Technology Services
>
>
>
>
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>


-- 
Berk Geveci
Kitware Inc.
28 Corporate Drive
Clifton Park, NY, 12309
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