Comment on "Line of Dirac Nodes in Hyperhoneycomb Lattices".

Recently, carbon hyperhoneycomb ($\mathcal{H}$-n) lattices have been proposed to be, through a one-$p$ orbital tight-binding (TB) model with nearest-neighbor (n.n.) hopping, a family of strong 3D topological insulators (K. Mullen, B. Uchoa and D. T. Glatzhofer, Phys. Rev. Lett. 115, 026403 (2015)) . In this Comment we show, through Density Functional Theory (DFT) and Extended H\"uckel Theory (EHT) calculations for the $\mathcal{H}$-0 lattice, that the TB Hamiltonian used by the authors is inadequate, invalidating the presented conclusions.