[vtkusers] vtkRectilinearGridToTetrahedra how to get 3D picture?

[Artem Babayan]

Hello.

I am trying to visualize 3D scalar data defined on rectilinear grid.
Apparently, vtkFixedPointVolumeRayCastMapper cannot render the data
from Rectilinear Grid directly. Paraview uses filter 'Tetrahedralize'
which is not present in VTK. I have tried to use
vtkRectilinearGridToTetrahedra as following:

      vtkSmartPointer<vtkFixedPointVolum> RayCastMapper> mapper_conc =
                   vtkSmartPointer<vtkFixedPointVolumeRayCastMapper>::New();

      vtkRectilinearGridToTetrahedra *rg2t =
vtkRectilinearGridToTetrahedra::New();
      rg2t->SetInputConnection(reader_grid->GetOutput()->GetProducerPort());
      mapper_conc->SetInput(rg2t->GetOutput());

but got the following runtime error:

 "Input port 0 of algorithm
vtkFixedPointVolumeRayCastMapper(0x2c90020) has 0 connections but is
not optional."

What am I doing wrong?

Best wishes
Artem