ST-CS-10-339-75
March 2002

SECTION IV

WEAPONS AND GUNFIRE  (S)

1.  Gunfire Analysis  (S)

A key aspect of any realistic shoot'em'up is the way in which the game emulates the behaviour of weapons.

Counter-Strike attempts to emulate realistic weapon behaviour by two devices; firstly, as the gun fires, the crosshair jerks up and left and right, erratically. Secondly, each bullet fired is offset by a random amount vertically and horizonally from the current position of the crosshair.

Exactly how much jerk and offset are applied to a gun at any given moment depends on three factors;

1. Length of the current burst of fire
2. Movement of the player
3. Which weapon is being used

The longer the current burst of fire, the more jerk and offset are applied, up to a maximum value for jerk and offset. In practise, this means most weapons are exactly accurate for their first shot and that the next two to four rounds form a short vertical column. After that, weapons rapidly reach maximal jerk and offset and at that point the crosshair movement and bullet offset are so large that meaningful aiming is no longer possible.

Player movement seems to apply a multiplier to the current values of jerk and offset. Being stationary means no change, running appears to reduce accuracy marginally (perhaps by 50 percent) but being airborne (jumping or being on a ladder) decreases accuracy hugely - perhaps by 200 percent.

Crouching appears to make no difference.

Finally, some weapons are more accurate than others, and have a lower maximum jerk and offset rating, as well as taking longer to reach that ceiling when fired.

The following footage demonstrates all these points. A silenced (to reduce muzzle flash to aid spotting fall of fire) M4A1 was fired from a ladder, thus emulating the airborne jerk and offset multiplier. Note the M4A1 is an accurate weapon. This video capture was attempted with an ak47, but the majority of shots fired from that weapon did not even connect with the white wall, going wide to the left and right and above.

The initial shots are reasonably well centered at the crosshair. Fairly rapidly, however, the gun goes wild and bullets are scattered everywhere.

The crucial point here, clearly illustrated in the footage, is that the path of each bullet is totally unrelated to the previous bullet.