In summary, we think the superior performance of TorsionDrive is because it optimizes multiple structures at the same grid point from different propagating directions. This procedure makes the TorsionDrive result less sensitive to the sometimes unpredictable convergence of geometry optimization methods to different local minima depending on starting conformation. This procedure, optionally augmented by using multiple starting conformations, results in a higher quality PES and much higher chance of finding relevant local minima. In addition, TorsionDrive saves human effort and wall time in troubleshooting and restarting crashed calculations due to its robustness against the sometimes unpredictable convergence failure of geometry optimizations.