[Paraview] Assistance/Suggestion With Animating Relatively Small Datasets Over Many Timesteps

[John.CTR.Mick at faa.gov]

     This is my first experience posting to the ParaView Mailing List; as 
well as my first project I am exploring with ParaView.  I hope I am 
posting this question to the correct audience.

     I am attempting to create an animation of our Solar System - at an 
extremely high update interval - perhaps plotting the position and 
velocity of significant solar system bodies over 165 Earth years at
a one day interval.  Initially I thought I would be able to work with CSV 
files to define a dataset which includes time, positional coordinates, and 
velocity vectors.  While testing this approach I managed to use the 
TableToPoints filter to create a visualization of a sample dataset; but I 
was not able to sequence over the individual timesteps.  So in effect you 
see all the positions a particular planet was at for the entire duration 
of the dataset.

I created a video of this test and made it available online:
     http://www.youtube.com/watch?v=XLPxx-2Zc9Q 

     Next I thought perhaps the CSV format was a little too general for 
what I needed, so I read the VTK file format document and migrated over to 
the XML VTK format.  It seems like there is no way to define time 
sequenced data natively within the file format itself?  ParaView expects 
the user to break the timesteps into individual files - with a numeric 
indicator in the filename to define the sequence.  If I were to take this 
approach, I could be looking at creating nearly 500,000 individual files 
to represent the entire duration of time I'm interested in plotting.  I 
feel like there must be a better way to do this.

     As a small improvement I thought I could at least combine all of the 
unique solar system bodies (Earth, Sun, etc.), into a single timestep file 
such as this:
          (filename: timeseries_2455562.vtu)

<?xml version="1.0"?>
<VTKFile type="UnstructuredGrid" version="0.1" byte_order="LittleEndian" 
compressor="vtkZLibDataCompressor">
  <UnstructuredGrid>
    <Piece NumberOfPoints="2" NumberOfCells="2">
      <PointData Vectors="Velocity" Scalars="Radius">
        <DataArray Name="Time" type="Float32" format="ascii">2455562 
2455562</DataArray>
        <DataArray Name="Radius" type="Float32" format="ascii">6371 
696000</DataArray>
        <DataArray Name="Velocity" type="Float32" NumberOfComponents="3" 
format="ascii">
          -2.982651603443954E+01 -5.304542013817379E+00 
-7.226846229160870E-04
          0 0 0
        </DataArray>
      </PointData>
      <Points>
        <DataArray type="Float32" NumberOfComponents="3" format="ascii">
          -2.567030301930377E+07 1.448508985971261E+08 
-3.607762965630511E+03
          0 0 0
        </DataArray>
      </Points>
      <Cells>
        <DataArray Name="connectivity" type="Int32" format="ascii">0 
1</DataArray>
        <DataArray Name="offsets" type="Int32" format="ascii">1 
2</DataArray>
        <DataArray Name="types" type="UInt8" format="ascii">1 
1</DataArray>
      </Cells>
    </Piece>
  </UnstructuredGrid>
</VTKFile>

The idea of this approach was to list all of the scalars and vectors for 
each corresponding body in a single file.  In this example the first 
listed scalar, vector, or coordinate point, is the Earth while the second 
set of values indicates the Sun's data.  By combining the bodies into a 
single file I could reduce the 500,000 files required down to some 60,000 
files....still undesirable but better.

However I would also like to segment the Points once inside the ParaView 
environment; so I can create a distinct pipeline for each body in the 
dataset.  One application for this would be to allow different Glyph 
rendering rules for the Sun and the Earth so I can make the Sun...have a 
Sun texture - and the Earth an Earth texture. 

After experimenting with this for awhile I found myself trying to 
implement a Programmable Filter.  The filter would take the Unstructured 
Grid for the given timestep, and given an index, extract the Point, 
Scalar, and Vector data from its input - then set only those values to the 
Output Unstructured Grid.  I currently have a script that looks something 
like this:

# CELLID 0 = EARTH
cellId = 0

# Obtain References To Input/Output Data
gridI = self.GetUnstructuredGridInput()
gridO = self.GetUnstructuredGridOutput()
dataI = self.GetInput()
dataO = self.GetOutput()
scalarI = dataI.GetPointData().GetScalars()
vectorI = dataI.GetPointData().GetVectors()

# Initialize Local Storage Arrays
newVector = vtk.vtkFloatArray()
newVector.SetName(vectorI.GetName())
newVector.SetNumberOfComponents(3)
newScalar = vtk.vtkFloatArray()
newScalar.SetName(scalarI.GetName())
newPoint = vtk.vtkPoints()
newPoint.SetNumberOfPoints(1)
newCell = vtk.vtkCellArray()

# Lookup CellId References
idCell = gridI.GetCell(cellId)
idCellType = gridI.GetCellType(cellId)
idPoint = gridI.GetPoints().GetPoint(cellId)
idScalar = scalarI.GetTuple(cellId)
idVector = vectorI.GetTuple(cellId)

# Populate New Local Cell Array with CellId Cell
newCell.InsertNextCell(idCell)

# Populate New Local Point Array With CellId Point
newPoint.SetPoint(0, idPoint)

# Populate New Local Scalars with CellId Scalar Tuples
newScalar.InsertNextTuple(idScalar)

# Populate New Local Vectors with CellID Vector Tuples
newVector.InsertNextTuple(idVector)

# Copy Local Cells, Scalars, Vectors, and Points Into Output Pipeline Data
gridO.SetPoints(newPoint)
gridO.SetCells(idCellType, newCell)
dataO.GetPointData().SetScalars(newScalar)
dataO.GetPointData().SetVectors(newVector)

The filter does achieve the desired effect for the cellID 0 - but when I 
switch the value of cellID to 1 (which should refer to the Sun's index) 
ParaView crashes hard - where I assume I am missing something, possibly 
requesting something out of bounds in memory.

I've been struggling with this problem for a little while now and thought 
to share my progress here; hopefully there is somebody out there with a 
little more insight that could help guide me towards either a conclusion 
with this implementation or a suggestion for a better approach.

Essentially - How can one give ParaView Point and Velocity vectors over a 
vast sequence of time without creating potentially hundreds of thousands 
of files on disc?  Does this Programmable Filter seem like a reasonable 
approach?  Is there a native feature I am missing that does this already? 
Is there some other file format other than VTK I could use to have 
ParaView understand this format of data?

Any thoughts, comments, or questions will be greatly appreciated.  :)

Thanks,
     John
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