[vtkusers] vtkTemporalData

[Erik Anderson]

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