[vtkusers] vtkTemporalData

[Gerrick Bivins]

Hi Erik,
I asked the very same question a couple of months back. John Biddiscombe was
very helpful in getting me up and running. Check out this thread for more
info (more towards the end of the thread will have the info you're
interested in):
http://www.nabble.com/TemporalDataSet-examples-td18096276.html

Basically, it is recommended to write a reader for your original data that
handles the temporal information keys (I looked at vtkEnSightReader.cxx for
an example) in RequestData and RequestInformation or use the
vtkFileSeriesReader interface in paraview.
 Gerrick


On 4/20/09 2:22 PM, "Erik Anderson" <eranders at sci.utah.edu> wrote:

> Hi Everyone,
>     I am trying to get some visualizations of pathlines/streaklines/etc
> out of VTK.  I have some time-varying data that I have created a
> vtkTemporalDataSet out of.  To do this, I use something like the
> following (in Python):
> 
> ds = vtk.vtkTemporalDataSet()
> ds.SetNumberOfTimeSteps(5)
> for i in range(num_time_steps):
>     ds.SetTimeStep(i, data[i])   #  data is a list of vtkStructuredPoints
> 
> 
> After the vtkTemporalDataSet is constructed, I would like to use the
> vtkTemporalDataSetAlgorithms using the new data as input.  For instance,
> I would like to use the vtkTemporalStreamTracer in conjuction with
> vtkTemporalPathLineFilter to take advantage of the time-varying vector
> field.  If I print out the vtkTemporalDataSet I generate, I get exactly
> the dataset I would expect - 5 children with the appropriate fields
> attached.  However, when I use a vtkTemporalStreamTracer, with the data
> as an input and a plane used to seed the lines in the source connection,
> I get the following error:
> 
> vtkCompositeDataPipeline (0x6bb3890): Algorithm
> vtkTemporalStreamTracer(0x7066260) returned failure for request:
> vtkInformation (0x723ab10)
>   Debug: Off
>   Modified Time: 1281919
>   Reference Count: 1
>   Registered Events: (none)
>   Request: REQUEST_UPDATE_EXTENT
>   ALGORITHM_BEFORE_FORWARD: 1
>   FORWARD_DIRECTION: 0
>   FROM_OUTPUT_PORT: 0
> 
> 
> 
> ERROR: In /home/eranders/env/VTK/Parallel/vtkTemporalStreamTracer.cxx,
> line 803
> vtkTemporalStreamTracer (0x7066260): No time step info
> 
> 
> Am I forming the dataset incorrectly?  I'm relatively confident that my
> pipeline is correct:
> 
> s = vtk.vtkTemporalStreamTracer()
> s.SetInput(ds)
> s.SetSourceConnection(seeds)
> 
> where seeds is a vtkPlane
> 
> Thanks in advance for any help!
> Erik Anderson
> 
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