You can look into [HXT](https://gitlab.onelab.info/gmsh/gmsh/tree/master/contrib/hxt https://gitlab.onelab.info/gmsh/gmsh/tree/master/contrib/hxt) for that. Mor

You can look into [HXT](https://gitlab.onelab.info/gmsh/gmsh/tree/master/contrib/hxt https://gitlab.onelab.info/gmsh/gmsh/tree/master/contrib/hxt) for that. More specifically [this file](https://gitlab.onelab.info/gmsh/gmsh/-/blob/master/contrib/hxt/tetMesh/exe/Delaunay_CLI.c https://gitlab.onelab.info/gmsh/gmsh/-/blob/master/contrib/h...) which shows how create the Delaunay tetrahedralization of a set of point using the tetMesh library. It's a shameless plug since I am the author of the HXT core and tet meshing stuffs.