The accuracy falloff of a module is a measurement of how quickly the module's accuracy drops as a target exceeds the module's optimal range. Accuracy is perfect when the target is within the module's optimal range (though turret tracking speed may still cause shots to miss). Accuracy does not affect damage dealt, only the chance to hit.
The probability P of hitting a target is calculated by P = 0.5((d − o)/f)2 where d = distance to target, o = optimal range, and f = accuracy falloff.
- Example: A ship has fitted a turret that has an optimal range of 10,000 m and an accuracy falloff of 5,000 m. When fired at a target that is within 10,000 m of the ship, the turret will always hit its target (unless the turret fails to track the target) and cause damage. Between 10,000 m and 15,000 m (the first falloff range), the accuracy gradually decreases to 50%, though each hit still does the same amount of damage. Continuing from 15,000 m to 20,000 m, the accuracy continues to decrease down to 6.25%, getting closer and closer to zero as the range continues to increase, though damage from a hit remains the same.
Some modules that have an optimal range do not have an accuracy falloff. These modules are completely ineffective on targets that are beyond their optimal range.
See also Falloff at Grismar's wiki