  We review achievements made in recent years in the field of numerical
modeling of ultra-relativistic projectiles propagation in oriented crystals,
radiation emission and related phenomena. This topic is highly relevant to the
problem of designing novel gamma-ray light sources based on the exposure of
oriented crystals to the beams of ultra-relativistic charged particles. The
paper focuses on the approaches that allow for advanced computation exploration
beyond the continuous potential and the binary collisions frameworks. A
comprehensive description of the multiscale all-atom relativistic molecular
dynamics approach implemented in the MBN Explorer package is given. Several
case studies related to modeling of ultra-relativistic projectiles (electrons,
positron and pions) channeling and photon emission in oriented straight, bent
and periodically bent crystals are presented. In most cases, the input data
used in the simulations, such as crystal orientation and thickness, the bending
radii, periods and amplitudes, as well as the energies of the projectiles, have
been chosen to match the parameters used in the accomplished and the ongoing
experiments. Wherever available the results of calculations are compared with
the experimental data and/or the data obtained by other numerical means.
