We also evaluated the effect of post-processing after coordinate generation. The default --gen3d option for Open Babel performs coordinate generation followed by MMFF94 geometry optimization and conformer searching, increasing processing time in favor of producing fewer poor geometries (i.e., incorrectly extended ring closure bonds). As illustrated in Table , we find that both methods improve RMSD, bond and angle errors and somewhat increase stereochemical accuracy (to 94.0%) at the cost of 10 -20× increased processing time. The current default Open Babel conformer search is a weighted stochastic rotor search, changing the likelihood of different dihedral angles on the basis of evaluated MMFF94 energies. That is, during the Monte Carlo search, a high-energy conformation will lead to lower likelihood of the associated dihedral angles being chosen in subsequent iterations.