The authors present a new Monte Carlo tool capable of simulating electron trajectories in nanotube forests, taking into account the underlying nanoscale nature of the material. The scattering angle distribution is adaptively modified at each step of the simulation according to the local environment (how the nanotubes are positioned, their diameters, and internanotube distances). This provides additional degrees of freedom in the Monte Carlo simulation that are directly related to the internal structure of the nanotube forest, allowing the model to closely match experimental data. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3511506]