Add SMTKFileWriter module for exporting Slicer scene as .aeva.smtk file which can then be loaded into aevaCMB application.

This merge request addresses aeva#115 (closed) and it was developed by @shreeraj.jadhav with input from @jcfr

It adds the SMTKFileWriter module enabling user to export a Slicer MRML scene as a .aeva.smtk json file along side with:

• Slicer segmentation saved as .vti
• Slicer surface models saved as .vtp
• Slicer solid models saved as .vtu

The exported file is saved with extension .aeva.smtk which can then be loaded into aevaCMB application.

Links:

• VTK file format at https://kitware.github.io/vtk-examples/site/VTKFileFormats/
• SMTK resource serialization at https://smtk.readthedocs.io/en/latest/tutorials/create_a_project/index.html?write-project-resource

Features

1. Export surface models as vtkPolyData (.vtp)
2. Export solid models as vtkUnstructuredGrid (.vtu)
3. Export Images/Volumes as vtkImageData (.vti)
4. Export scene as smtk json format (.aeva.smtk)
5. Individual component files (vtp, vtu, vti) are saved under a subfolder with the same name as the parent filename.
6. Components undergo transformation hardening before saving, thereby carrying forward any registrations/transformations applied within Slicer.
7. File names of component files are made more readable by using the user-specified MRML node name as a prefix to the file followed by the respective uuid. The prefix undergoes string sanitization to ensure that it is compatible as a file name.

External projects

To support this, the following external projects have been added:

• External_aeva-session.cmake
• External_Boost.cmake: Currently required Boost to be always be installed on the system. See aevaslicer#10
• External_Eigen3.cmake
• External_MOAB.cmake
• External_Netgen.cmake
• External_nlohmann_json.cmake
• External_pegtl.cmake
• External_smtk.cmake
• External_vtkFiltersParallelDIY2.cmake
• External_vtkIOParallelExodus.cmake
• External_vtkvtkm.cmake