[Paraview] Convert file types with python

[David Doria]

On Sat, Apr 25, 2009 at 2:53 PM, pat marion <pat.marion at kitware.com> wrote:

> Hi David,
>
> Good question.  I've worked with obj files before, but never in vtk.
> After a quick read of vtkOBJExporter, I think I can answer your
> question.  I encourage you to take a look at the source code for
> vtkOBJExporter.cxx, it's actually quite readable.  Here is what it
> does:
>
>
> The exporter takes a renderer, gets the actors from the renderer, and
> loops for each actor.  For each actor, it calls
> vtkOBJExporter::WriteAnActor.  This method gets the material
> properties from the actor and writes them to the .mtl file.  Then it
> gets the actor's dataset.  If the dataset is not polydata, it converts
> it to polydata by pushing it through the vtkGeometryFilter.  Then it
> writes the polydata's geometry to the .obj file.
>
>
> If you have some time and you want to improve this file, it might be
> helpful if you pulled some of the code from
> vtkOBJExporter::WriteAnActor and put it into a new subroutine named
> something like vtkOBJExporter::WriteAPolyData.  Then you could use
> this method to write a .obj file from a polydata if you are not
> interested in having an accompanying.mtl file.
>
>
> Pat
>

Pat, I did exactly what you said and now have a function:
void WriteAPolyData(vtkSmartPointer<vtkPolyData> pd, std::string
&OutputFilename)
that seems to work!

At first I tried to put it in the public section of vtkOBJExporter.h/.cxx
and recompile Paraview/VTK, but it tells me there is a compiler parsing
error (there is nothing wrong with the syntax because it compiles fine
"outside" of VTK).

In vtkOBJExporter.h, I added
#include "vtkSmartPointer.h"
#include "vtkPolyData.h"
#include <string>

And under:
  void PrintSelf(ostream& os, vtkIndent indent);
I added:
void WriteAPolyData(vtkSmartPointer<vtkPolyData> pd, std::string
&OutputFilename);

I put the function definition in vtkOBJExporter.cxx.

After fighting that for a while (with no resolution) I moved the declaration
outside the class (to the very bottom of vtkOBJExporter.h (as the function
doesn't actually rely on anything in the class anyway) and it compiled fine.
Can I commit this function? I feel like it would probably be useful for many
users. (I don't have write access).

As a side note : I have QT4.5 and cmake (with the latest cvs paraview/vtk)
wouldn't let me proceed installing vtk because the qt version was too high.
I commented out that check in the CMakeLists.txt file and it seemed to work
just fine... is there a reason that check is still there? Maybe it should be
decreased to a warning instead of a show-stopping error?

Thanks,

Dave
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