VTKFortran

Explicitly designed to be thread and processor safe, enabling concurrent file writing under OpenMP or MPI, which is critical for high-performance computing simulations as stated in the README.

Provides a native, object-oriented interface in Fortran 2003+ without external C/C++ bindings, simplifying integration into Fortran projects and avoiding cross-language dependencies.

Supports all major VTK XML topologies including structured, unstructured, rectilinear grids, and composite datasets like multi-block and parallel partitioned files, as detailed in the features table.

Offers multiple license options (GPL, BSD, MIT), allowing use in both open-source and commercial projects without restrictive terms, as highlighted in the copyrights section.