  We present a detailed description of a new hadronic multiparticle production
model for use in neutrino interaction simulations. Its validity spans a wide
invariant mass range starting from pion production threshold. This model
focuses on the low invariant mass region which is probed in few-GeV neutrino
interactions and is of particular importance to neutrino oscillation
experiments using accelerator and atmospheric fluxes. It exhibits reasonable
agreement with a wide variety of experimental data. We also describe
measurements that can be made in upcoming experiments that can improve modeling
in areas where uncertainties are currently large.
