PFC, or Particle Flow Code, is a general-purpose distinct-element modeling framework available as two- and three-dimensional programs, PFC2D and PFC3D. It is designed to simulate synthetic granular and solid materials as assemblies of variably sized rigid particles, including disks, spheres, rigidly connected clumps, and convex polygons or polyhedra. It provides an efficient and flexible way to model the motion, interaction, breakage, flow, deformation, and failure of particle systems across geomechanics, mining, civil engineering, materials processing, and industrial design. PFC is especially useful for problems where the behavior of a material emerges from particle-level contacts, bonding, friction, rearrangement, fracture, or flow rather than from a continuous mesh. Users can represent bonded materials such as rock, concrete, or cemented soil, as well as loose granular materials such as sand, gravel, ballast, ore, powders, and grains.