Support vtkPolyData as input in run pipeline browser

[a3VonG]

Hi! I have created a pipeline that modifies vtkPolyData. Now I'm trying to find the best way to pass a vtkPolyData to runPipelineBrowser as an input. However vtkPolyData is not a supported IOType as input (it is for output). Why is this?

I have considered the following options as workarounds:

• Use/write a function to convert the vtkPolyData to an ITK mesh. Are there any functions available that can do this efficiently? I'm not a big fan of this approach as in the C code I would have to convert the mesh again to a vtkPolydata.
• Pass the points and the cells as binary arrays and build the Polydata from these arrays again in C++. I'm not very comfortable with C++ so any help/examples would be appreciated.

I can imagine that these options are not really optimal so I would be happy the hear what the better approach is!

[thewtex]

Hi @a3VonG !

I have created a pipeline that modifies vtkPolyData.

Nice!

However vtkPolyData is not a supported IOType as input (it is for output). Why is this?

Correct -- we are missing the C++ code for this, identified in issue https://github.com/InsightSoftwareConsortium/itk-js/issues/254, we need a vtkJSONDataSetReader similar to the current vtkJSONDataSetWriter.

Use/write a function to convert the vtkPolyData to an ITK mesh. Are there any functions available that can do this efficiently?

Not currently, but see the classes:

• https://github.com/InsightSoftwareConsortium/ITKVtkGlue/blob/master/include/itkMeshToVTKUnstructuredGridFilter.h
• https://github.com/InsightSoftwareConsortium/ITKMeshToPolyData/blob/master/include/itkMeshToPolyDataFilter.h

for references to go the other direction.

Pass the points and the cells as binary arrays and build the Polydata from these arrays again in C++. I'm not very comfortable with C++ so any help/examples would be appreciated.

Yes, this is preferred -- we need a vtkJSONDataSetReader supporting PolyData.

[thewtex]

The conversion function functions are demonstrated here: https://kitware.github.io/vtk-js/examples/ItkWasmGeometry.html