Accuracy (DX)

In Deus Ex, accuracy affects the use of weapons. Each weapon has a base accuracy, which is subject to various modifiers.

Overview

Accuracy is displayed in the inventory interface as a percentage value up to 100%.

• An accuracy of less than 100% means that attacks output by the weapon will deviate from the center of aim by a randomly computed offset. The further that the accuracy is below 100%, the greater that this offset tends to be.
• An accuracy of 100% means that aim is "perfect." For weapons other than shotguns, 100% accuracy means that repeated shots will always hit the exact same spot, without any random deviation from the center of aim.

The inventory interface truncates decimal values when displaying accuracy. For example, an accuracy of 87.5% will be displayed as 87%. However, internal calculations based on accuracy will still account for the decimal values.

Accuracy is reflected by the targeting reticle. The more that the reticle is closely clustered toward the center, the higher the accuracy. Active convergence of the reticle is typically the result of the "standing still" accuracy bonus, described below.

Accuracy also affects scope sway when aiming through the scope of the sniper rifle or a weapon that has the scope modification installed. Scope sway is entirely eliminated when accuracy is 100%.

Internal representation

Internally, accuracy is represented by a parameter whose value is 0 or higher. This parameter has an inverted scale in which higher values represent lower accuracy, lower values represent higher accuracy, and a value of 0 represents perfect accuracy. The internal accuracy parameter and the percentage representation of accuracy can be converted from one to another as follows:

• Percentage Accuracy = 100% × ( 1 – ( Internal Accuracy / 2 ) )
• Internal Accuracy = 2 × ( 1 – ( Percentage Accuracy / 100% ) )

Internal accuracy is initially set to the weapon's base internal accuracy, and may then be reduced by accuracy bonuses. When a weapon is fired, two random numbers are generated, respectively corresponding to a random pitch-axis offset and a random yaw-axis offset of the aim. These offsets are then scaled (multiplied with) the value of internal accuracy, such that offsets tend to be greater when the internal accuracy value is higher.

When the internal accuracy value is reduced to 0, all random pitch-axis and yaw-axis offsets are reduced to zero, resulting in perfect accuracy. When accuracy is less than perfect, the random pitch-axis and yaw-axis offsets will cause the shots to be randomly distributed over a square projection.

Similarly, to determine scope sway, the internal accuracy value is multiplied by random pitch-axis and yaw-axis offsets.

Base accuracy

Each weapon has a base accuracy upon which modifiers are applied. The weapon's base accuracy is stored as a base value for the internal accuracy parameter.

• For example, the assault rifle has a base internal accuracy of 0.70, which corresponds to 65% accuracy in the percentage representation.

Accuracy mods

The base accuracy of a weapon can be improved by installing accuracy modifications. Each accuracy modification improve the weapon's base accuracy by reducing its internal accuracy value by 10% of the weapon's (default) base accuracy.

• For example, given that the assault rifle has a base internal accuracy of 0.70, each successive accuracy mod reduces the internal accuracy value by 0.07, which is 10% of the original base value of 0.70.

Therefore, the accuracy gain per upgrade, in the percentage representation of accuracy, can be computed as follows:

• Accuracy per upgrade (%) = ( 100% – Base Percentage Accuracy ) / 10

Accuracy mods are permanent adjustments to the accuracy of the weapon. This adjusted accuracy is then treated as the base accuracy to which the modifiers described below are applied.

Since accuracy mods are implemented as a percentage reduction of the internal accuracy value, weapons that are initially less accurate (i.e., having a higher base internal accuracy value) receive less of a boost from accuracy mods as compared to weapons that are initially more accurate.

Standard modifiers

The following modifiers are applied in an additive (or subtractive) manner to the weapon's base accuracy (after accuracy modifications have been accounted for). The effects of these modifiers are shown below in the percentage scale.

All of the following accuracy modifiers are reflected by the on-screen targeting reticle. The weapon skill and targeting bonuses are also are reflected in weapon stats in the the inventory interface.

Weapon skill bonus

Weapon skills provide the following passive bonuses to accuracy in the form of an additive boost.

Untrained	Trained	Advanced	Master
+0%	+5%	+12%	+25%

Targeting bonus

The Targeting augmentation provides the following bonuses to accuracy in the form of an additive boost. This bonus is applied only if the augmentation has been activated.

Tech 1	Tech 2	Tech 3	Tech 4
+2.5%	+5%	+7.5%	+10%

Damaged body parts penalty

Damage to the arms or the head will incur accuracy penalties as follows. These penalties are applicable to humanoid NPCs as well as the player. The maximum penalty, with fully damaged arms and head health below 67%, is 55%.

These penalties can be compensated by the accuracy bonuses listed in this section. For example, the Sniper Rifle with master skill level and tech 4 targeting would have a total of 110% accuracy.

Body Part	Condition of Body Part	Accuracy Penalty
Right Arm	< 67% health	-5%
	< 34% health	-10%
	0 health	-25%
Left Arm	< 67% health	-5%
	< 34% health	-10%
	0 health	-25%
Head	< 67% health	-5%

"Standing still" bonus

Standing still will progressively improve the player's accuracy, up to a maximum of 95%. Therefore, any weapon can achieve an accuracy of 95% simply by standing still for a sufficient duration of time. The rate at which accuracy is improved by standing still depends on the player's weapon skill (and also Targeting, if activated). A higher weapon skill level will result in a quicker rate.

This bonus is available only to the player, and is not available to NPCs. Furthermore, the game makes no distinction between standing and crouching for purposes of applying this bonus. Therefore, crouching does not approve accuracy compared to standing.

This bonus is not applied if the player's accuracy is higher than 95%.

This bonus has no cap and will keep increasing while the player stands, allowing the player to stand in place for hours and keep the full bonus while moving.

Hidden modifiers

The following modifiers are hidden adjustments to accuracy that are not reflected by the on-screen targeting reticle, and are also not reflected in the in-game inventory interface. These modifiers only affect instant-hit weapons (including all firearms), and do not affect weapons that fire projectiles.

Scope mod accuracy penalty

Attaching a scope modification to a pistol or stealth pistol will decrease the weapon's accuracy by 10% when the weapon is used outside of scope mode. This penalty cannot be overridden by additional accuracy bonuses, because it is applied after accuracy is capped to 100%. Therefore, the maximum accuracy that a scoped pistol or stealth pistol can have when the scope is not activated is 90%, even if the weapon has attained a nominal accuracy rating of 100%, and even if additional accuracy bonuses (such as the bonus from Targeting) are applied on top of the 100% accuracy rating.

This penalty does not apply to the mini-crossbow, plasma rifle, and GEP gun, which are projectile weapons.

Laser mod accuracy bonus

Attaching a laser modification to an instant-hit weapon enables it to fire at perfect accuracy when the laser sight is turned on. Internally, the value of the internal accuracy parameter is set to zero, resulting in 100% accuracy.

The laser mod accuracy bonus does not apply if the scope mod penalty is in effect. Consequently, attaching the scope mod negates the accuracy bonus provided by the laser mod when the weapon is used outside of scope mode.

The laser mod accuracy bonus does not apply to the mini-crossbow and the plasma rifle, which are projectile weapons.

Accuracy of NPCs

Non-player characters (NPCs) generally follow the same accuracy rules as the player character, except that they are subject to a further accuracy modifier (BaseAccuracy), which is typically an accuracy penalty, and are not eligible for accuracy bonuses derived from weapon skills, augmentations, and standing still. Combatant-type NPCs, such as common troopers, have a default accuracy modifier of -10% (for example, the accuracy modifier would lower the 65% base accuracy of the assault rifle to 55%). However, in the single player campaign, this default value is very often overridden by custom values assigned to particular NPC characters. In general, accuracy modifiers typically fall within the range of -5% to -45%.