ParaView has a .nrrd reader and it works fine on this data, so you could either borrow PV’s nrrd reading code path for your VTK program, or more easily import it once in a ParaView session and export into .vti to work with in your program.
ParaView has a .nrrd reader and it works fine on this data, so you could either borrow PV’s nrrd reading code path for your VTK program, or more easily import it once in a ParaView session and export into .vti to work with in your program.