The usefulness of these non-conventional torsion degrees of freedom is further enhanced by TorsionDrive's robustness in building a smooth PES even for difficult systems. As an example, we conducted dihedral scans on a molecular motor that works by rotating around its torsion angle as shown in Figure . The subject molecule is a crowded and strained alkene where rotation of central double-bond torsion has to overcome a considerable energy barrier. Between the two sides of the rotation barrier there are also large structural differences such as ring pucker flips. In this example, rotation around the central double bond is characterized by a torsion angle defined by four non-consecutive atoms, because using consecutive atoms to define torsion would lead to poor projection of the barrier onto the scanned coordinates.