[Paraview] Scripting and new VTK objects

[Tim Gallagher]

We had looked at the programmable source, but we didn't know how to access the XDMFReader. But, with what you pointed out, it looks like that isn't hard so I'll give it a shot. 

Out of curiosity, what is wrong with the approach I was trying? Is it possible to completely copy information from one source in a pipeline into another source in a pipeline and delete the original source? Why does Fetch() show data inside the DataObjectGenerator but no filter can seem to access it? 

Thanks for the help, 

Tim 

----- Original Message -----
From: "pat marion" <pat.marion at kitware.com> 
To: gtg085x at mail.gatech.edu 
Cc: paraview at paraview.org 
Sent: Wednesday, February 9, 2011 4:55:05 PM 
Subject: Re: [Paraview] Scripting and new VTK objects 

Hi Tim, 

Have you looked at the python programmable source? With the python programmable source you can specify python code to run on the server side. You won't be able to use paraview python api though. Instead of 

XDMFReader(FileName=...) 

it would look like: 

reader = vtkXDMFReader() 
reader.SetFileName(...) 
reader.Update() 
data = reader.GetOutput() 

You can find examples of the python programmable source: 

http://www.paraview.org/Wiki/Python_Programmable_Filter#Generating_Data_.28Programmable_Source.29 
http://www.paraview.org/Wiki/Here_are_some_more_examples_of_simple_ParaView_3_python_filters . 

Pat 


On Wed, Feb 9, 2011 at 4:20 PM, Tim Gallagher < tim.gallagher at gatech.edu > wrote: 


Hi, 

I've searched online at length for this and couldn't find the answer, so hopefully somebody here can help me. 

I am trying to create a new VTK object (vtkMultiBlockDataSet) composed of portions of manipulated data from some other VTK object (in this case, a vtkStructuredGrid). I then want to delete the vtkStructuredGrid object and visualize the new vtkMultiBlockDataSet. 

So, here's the general outline of what I do in a python script: 

newSource = DataGeneratorObject(Program="MB{}") 
newSource.UpdatePipeline() 

newData = servermanager.Fetch(newSource) 
newData.SetNumberOfBlocks(64) 

for n in range(0,64): 
myData = XDMFReader(FileName=...) 
myData.UpdatePipeline() 

localData = servermanager.Fetch(myData) 

<manipulate the data> 

newData.SetBlock(n,vtk.vtkStructuredGrid()) 
newData.GetBlock(n).DeepCopy(localData) 

Delete(localData) 
Delete(myData) 

newData.DataHasBeenGenerated() 
newSource.UpdatePipelineInformation() 
newSource.UpdatePipeline() 

With all that done, if I try to apply a filter to newSource, it doesn't work. The data is definitely inside newData -- I can print it out and such, even after I delete the localData (which is why I used DeepCopy). 

But I don't know how to send that data back to the server. Or, maybe I don't need the DataObjectGenerator -- if that's the case, how do I create a local VTK object and then send it to the server to visualize? 

Hopefully that example is clear... I appreciate any help you guys can provide. It would be easiest if I could create my own custom reader, but I can't do that because we use Paraview on a lot of machines that we can't recompile to include the new plugin. 

Thanks, 

Tim 
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