The architecture of ParaView allows extending its functionality by creating plugins which can be loaded as dynamic libraries without recompiling ParaView.

The main mesh filetypes we are handling in our lab are .ugrid generated by AFLR3 and used widely within FUN3D, .meshb from INRIA Gamma Team and .su2 from the SU2 solver. Unfortunately there is no support for these from Paraview. Fortunately there is documentation for creating readers (plugin guides).

Here is the boilerplate for writing a reader for an unstructured grid based on the Paraview wiki.

#ifndef vtkUGRIDReader_h
#define vtkUGRIDReader_h

#include "vtkUnstructuredGridAlgorithm.h"
#include "vtkObjectFactory.h"

class vtkUGRIDReader : public vtkUnstructuredGridAlgorithm
{
public:
  static vtkUGRIDReader* New();

  vtkTypeMacro(vtkUGRIDReader,vtkUnstructuredGridAlgorithm);

  void PrintSelf(ostream& os, vtkIndent indent) VTK_OVERRIDE;

  vtkSetStringMacro(MeshFile);

  vtkGetStringMacro(MeshFile);

protected:
  vtkUGRIDReader();
  ~vtkUGRIDReader() VTK_OVERRIDE;

  int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *) VTK_OVERRIDE;
private:
  char* MeshFile;
  vtkUGRIDReader(const vtkUGRIDReader&) VTK_DELETE_FUNCTION;
  void operator=(const vtkUGRIDReader&) VTK_DELETE_FUNCTION;
};

#endif

The only important part is the RequestData function which looks like that

int vtkUGRIDReader::RequestData( vtkInformation *vtkNotUsed(request),
                                 vtkInformationVector **vtkNotUsed(inputVector),
                                 vtkInformationVector *outputVector)
{
    // get the info object
    vtkInformation *outInfo = outputVector->GetInformationObject(0);

    // get the output
    vtkUnstructuredGrid *output = vtkUnstructuredGrid::SafeDownCast( outInfo->Get(vtkDataObject::DATA_OBJECT()));

    if (!this->MeshFile)
    {
        vtkErrorMacro(<<"A File Name for the Mesh must be specified.");
        return 0;
    }

    bool res = read_mesh(this->MeshFile,output);
    output->Squeeze();
    if (not res)
        return 0;
    return 1;
}

In the read_mesh function we need to populate the output pointer using a custom reader.

Below you may find the repository for each of the readers.

Update 2020.03.16

The code on github has been updated to support ParaView 5.8.0. There are some significant changes in the way plugin are written and compiled within ParaView. The new documentation is here. Compilation is now handled by the official paraview plugin builder.