Ion collisions with beam-pipe walls are a significant source of secondary electron clouds and desorbed neutral gasses in particle accelerators. Ions may reflect from beam-pipe walls and undergo further collisions downstream. These effects can cause beam degradation and are expected to be problematic in the design of heavy ion accelerators. The well-known SRIM code provides physically based Monte Carlo simulations of ion-wall collisions. However, it is difficult to interface SRIM with high-performance simulation codes. We present details on the development of a package of Python modules that integrate the simulation of ion-wall interactions at grazing incidences with the high-performance particle-in-cell and electron cloud codes WARP and POSINST. We have a Python-based set of routines that calculate reflected angles and energies of ions that strike beam-pipe walls. The results are based on interpolation of benchmark simulations run in SRIM for a variety of relevant incident angles and energies.