  In this report we present simulated event numbers, for various MC generators,
for pion production in $\nu_{\mu}$ CC reactions on $\nucl{16}{O}$. For the
simulation we used four different neutrino interaction generators: GENIE,
FLUKA, NEUT, and NuWro, as proposed during the 45th Karpacz Winter School on
neutrino interactions. First we give a brief outline of the theoretical models
relevant to pion production. We then present results, in the form of tables
showing the occupancy of primary and final state pion topologies, for all the
generated samples. Finally we compare the results from the different generators
and draw conclusions about the similarities and differences. For some of the
generators we explore the effect of varying the axial mass parameter or the use
of a different nuclear model.
