CrystalTrace is a Monte Carlo raytracing algorithm for simulating radiative transfer in ice clouds with different crystal shapes and orientations. Integrated into libradtran's MYSTIC solver, it enables efficient, realistic simulations of ice alongside water clouds. By computing single-scattering properties online at the crystal scale, it eliminates the need for precomputed lookup tables, improving efficiency and angular resolution for satellite, airborne, and ground-based observation retrievals.