  The Atomic Cluster Expansion (ACE) [R. Drautz, Phys. Rev. B, 99:014104
(2019)] provides a systematically improvable, universal descriptor for the
environment of an atom that is invariant to permutation, translation and
rotation. ACE is being used extensively in newly emerging interatomic
potentials based on machine learning. This commentary discusses the ACE
framework and its potential impact.
