[Paraview] Python scripting: Updating PVDReader source when pvd file has changed and rendering latest time step

[Utkarsh Ayachit]

The vtkPVDReader (you may want to look at it's superclasses as well)
does not re-read the XML file, unless the reader is modified. What you
really need, is somehow call "Modified()" on the reader. One way would
be setting the filename to empty (then call
vtkSMPRoxy::UpdateVTKObjects()) and then setting it back  (and again
calling vtkSMProxy::UpdateVTKObjects()".

Utkarsh

On Fri, Mar 19, 2010 at 8:40 AM, Florian Rathgeber <frat at kth.se> wrote:
> Hi,
>
> I'm trying to get ParaView to work in an interactive context for
> numerical simulations. The first goal is to have ParaView visualize time
> steps as they are output by the solver (vtu for individual steps, pvd as
> collection). I searched the wiki, mailing lists etc. and it seems this
> cannot be done easily.
>
> My current approach uses the python scripting interface. I open a socket
> in python and wait for messages from the solver that a time step was
> finished and a new file written out. When this happens for the first
> time I initialize the visualization, i.e. load the pvd file and set some
> basic properties. For every subsequent event I set ViewTime to the
> latest sample and re-render the view. Is there a more elegant way to do
> that?
>
> This works as long as the pvd file contains all the expected time steps
> from the beginning. But the solver updates the pvd file for every vtu
> file written out and appends it to the collection. Hence, when I
> initially load the pvd, I only have the first time step. I tried all
> methods PVDReader provides but there seems to be no way to re-read the
> file of a PVDReader source. Did I miss something?
>
> I wonder if it might be a better option to try to realize this as a
> plugin, since in the end is should also be possible to send messages
> back to the solver to trigger a parameter change for the next time step
> while the simulation is running. As I'm not so familiar with the VTK /
> ParaView source and have no experience writing ParaView plugins I'd be
> happy to get some input or estimate if that is achievable in a
> reasonable amount of time.
>
> Best regards,
> Florian
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