Direct fire or line-of-sight fire refers to shooting of a ranged weapon whose projectile/ordnance is launched directly at a target within the line-of-sight of the user. Direct fire weapons typically have a sighting device to ensure accuracy and must have an unobstructed view to the target with no obstacles or friendly units in between, meaning that they can only effectively engage targets that are in enfilade. Conversely, direct fire units are also directly exposed to return fire from the target unless they are shooting from a position of defilade or concealment.
Direct fire is in contrast to indirect fire, which refers to firing a projectile on a curved ballistic trajectory or delivering self-accelerated munitions capable of long range and various degrees of homing abilities to alter the flight path. Indirect fire does not need a direct line-of-sight to the target because the shots are normally directed by a forward observer who provides the coordinates and calibrations needed to hit the target. As such, indirect-fire weapons can shoot over obstacles or friendly units and the weapons can be concealed from counter-battery fire.
