“…Among the methods that have been shown to possess certain regularisation effects in localisation problems there are moving least square (MLS) and reproducing kernel (RK) approximations, as well as methods based on strain smoothing techniques [Liu et al, 1999, Li et al, 2000, Chen et al, 2004, 2007, Wang and Li, 2012, Pozo et al, 2014. As strain smoothing methods, also the smoothed point interpolation methods (SPIMs) discussed in this manuscript have been shown to exhibit regularisation properties, as illustrated by Gori et al [Gori et al, 2019b], both alone as well as when combined with other regularisation strategies, like the micropolar continuum theory [Gori et al, 2019a,c]. Particle methods, like the SPH, have also been shown to be capable to deal with strain-softening problems [Vignjevic et al, 2014].…”