“…Since the 1980s, various non-disc/spherical or irregular particle shapes have been proposed in DEM including ellipses [16,17], ellipsoids [18], super-quadrics [19], cylinders [20], dilated or Minkowski-sum generated shapes [21,22,23], poly-ellipsoids [24,25] and poly-super-ellipsoids [26], polygons [27,28] and polyhedra [29,30,31,32]. More recent inclusions are level-set defined shapes based on CT scanned images [33], and analytical function represented smooth shapes, such as Fourier series-based for 2D shapes [34], NURBS (or B-spline) based [35] 3D shapes, spherical harmonic represented 3D objects [36,37], and isogeometric representation of 3D surfaces [38,39]. No doubt, these shapes significantly enhance the shape representation capability of DEM for industrial applications.…”