Anatomy of a AC

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The structure of an AC is standardized and modular, consisting of a number of parts which are fitted together in the AC Garage.

Required Parts
An AC must have all of these parts in order to function, or it will be declared incomplete.


Head
Contains visual sensors. May also contain radar and computing equipment. Some heads are better armoured than others, but at the cost of lacking extra sensor equipment. The radar and sensor equipment is broken down into several categories including Bio-Sensor, Noise Canceller, Night Vision, Missile Sensor and Auto-Map.

In Armored Core: Nexus onward, the stability of the head is now factored in when determining the stability of an AC, whereas traditionally it had only been affected by the legs and optional parts. Light ACs and others with weak stability generally tend to stick to the few heads with high stability, while heavier ACs can use heavier heads with weaker stability stats.

Auto-Map: allows a player to check the map screen of the game and see the whole area map of a mission. Heads without the Auto-Map function can only see a limited portion of the area.
Bio-Sensor: allows an AC to detect and target biological organisms, which appear in many of the games.
Missile Sensor: detects incoming missiles on the radar screen so that a player has the chance to dodge them before they hit. If a head has a radar but no Missile Sensor, the ability can be supplemented by an Optional Part providing this ability or a radar unit equipped with the sensor.
Noise Canceller (Armored Core - Silent Line: Armored Core): appeared in previous games and was a prelude to Nexus 's 'vs ECM'. It helps an AC recover from electronic interference.
Night Vision (Armored Core: Nexus onward): Night Vision initiates automatically and lights up an area that would otherwise be too dark to see anything. It is akin to modern night vision goggles and cameras.
Vs. ECM (Armored Core: Nexus onward): reflects the ability of the AC to counter high levels of electronic interference. These may be the result of ECM pods used by an arena opponent or of mission-specific environmental hazards. Back radars, FCS systems, and optional parts can boost this level higher.

Core
The 'torso' of the mech. It is the 'armored core' from which the mech and the game series take their name. The human pilot sits inside the core.

Cores come in different weights to suit different styles of robot; the lighter ones are less well protected but more suitable for more mobile ACs. Similarly, there are highly defensive heavyweight cores.

Cores contain a number of slots into which Optional Parts can be placed to improve its operation. Also, some cores have built-in anti-missile systems.

As the series has progressed, new features for cores have appeared:

Overboost (Armored Core 2 onward): a high powered booster system that operates in combination with the external or leg based booster of an AC. When activated, it allows the player's AC to move at amazingly high speeds, but can only be used to move forward, left, right, or diagonally left or right at a forward angle, backward movement is impossible. While it offers a tremendous amount of extra speed, Overboosting both drains energy very quickly and causes a massive increase in the core's heat level when initially used. These two factors heavily limit the amount of time an Overboost function can be used.
Exceed Orbit (Armored Core 3 onward): Exceed Orbit (EO) cores contain one or more orbital pods that can be deployed to hover above the AC and retracted at will. They automatically target and shoot enemies. The rate of fire, power, and field of vision for EO pods varies from model to model. For EO pods with energy weapons, the ammunition supply gradually regenerates when not in use. Two important factors that limit Exceed Orbit usage are the small amounts of added heat that occur whenever an EO pod is deployed, as well as the energy drain from the pod firing. EO Cores with solid ammo do not suffer from an energy drain while firing but their ammo cannot be replenished once depleted.
Hanger Unit (Armored Core: Nexus onward): any core with this unit can hold one spare piece of equipment for each hand. Only small devices can be stored inside this unit, for example, a hand gun or an energy shield generator. Some cores are equipped with both Overboost and Hanger functions but there are no Exceed Orbit cores with Hangers.

Arms
There are two types of arms; normal arms capable of holding weapons, and weapon arms that are weapons:

Normal arms have various differing attributes; the most important are the weight and defensive qualities, which are usually related - heavier arms are better armored. Other attributes are recoil control, which keeps the arm steady while firing, and reaction speed, which determines how quickly the robot can swing a laserblade.
Weapon arms sometimes possess two different firing modes, and are more powerful than ordinary weapons because they can be fired from two arms at once. However, they are greatly lacking in defense compared to normal arms. Weapon arms can be useful in keeping the weight of an AC down, as they are lighter than having separate arms and weapons but now are generally outclassed by Normal arms with weapons. Unlike Normal arms , Weapon arms cannot be tuned.

Legs
The legs support the AC on the ground and determine how it moves, and are usually the part by which an AC is classified. There are several different kinds of legs:

Humanoid — classic bipedal humanoid-style. Comes in many different weights, speeds and strengths. Humanoid ACs are limited in that they must kneel down to use many of the back-unit weapons (except for missiles and rockets). This takes time and also leaves them unable to move while firing.
Heavy Legs are well armoured and can support heavy weights but very slow.
Light Legs are very fast but have very low AP and weight limits.
Standard Legs are a balance between the other two types, with average AP, speed and weight limit. These legs are always equipped on the default AC that the player is provided at the start of each game.
Reverse-Joint — also bipedal, these legs resemble those of a bird. Reverse-jointed ACs tend to be faster than standard humanoid models while still having a reasonable carrying capacity; they can also jump higher. However, they have the same problem with back weapons as standard bipeds. They are not as well-armoured as bipeds, have less cooling, and low defensive stability. However, reverse-joint legs drain less energy from the generator than other leg types.
Four Leg — quadrupedal, similar to a spider. Four-legged ACs tend to be fast and have the ability to fire back weapons while moving. However most quads, as they are known in fan circles, cannot support heavy weights, are less well-armored than bipeds, and use high amounts of energy. In the earlier games ACs equipped with quad legs appeared to hover or roll, in the more recent Armored Core games they physically walk.
Tank Legs — slow and heavy, but very well armored and can support massive loads. Tank ACs can fire any weapon even if moving or airborne. As these kind of legs don't have any joints, they cannot jump, instead using built-in boosters to thrust upward. A disadvantage of this is that if the generator has been emptied and is recharging, the AC cannot leave the ground, unlike legged ACs which can jump.
Tank tracks - uses a caterpillar track to move.
Hover tank - uses hovering technology to improve speed, while sacrificing some of the armour and load carrying ability of the tank track legs.
Hover Legs — floating platforms that do not touch the ground. Hover ACs are the fastest and most maneuverable of all ACs and can travel over water; a huge advantage on aquatic missions. They are, however, the least armored of all the leg types and can only support very light loads. They suffer the same limitations as bipeds with regards to back-unit weapons. Like Tank ACs, Hover ACs cannot jump and have built-in boosters instead, and suffer the same problem of being unable to leave the ground if the generator is recharging.

FCS
The FCS or Fire Control System is the targeting computer, and controls weapon targeting and missile lock-ons. There are several different kinds, which vary on several attributes such as lock-on speed, maximum lock-on range, maximum lock-on number, or shape and size of lock-on area, suitable for different styles of weapons.

Missile FCS — FCS designed for use with missiles normally have a long vertical lock box, lock on very quickly with missiles and have a long detection range.
Sniper FCS — FCS designed for sniper rifle or cannons normally have a small square lock box, lock on very slowly with missiles and have an extremely long detection range.
Rifle FCS — FCS designed for rifle, pistol or shotgun weapons normally have a wide horizontal lock box, lock on rather slow with missiles and have a fairly short detection range.
Standard FCS — Standard FCS don't show any particular preference when it comes to lock time, have an even square lock box and a balanced lock on distance.

Booster
Boosters enable an AC to move quickly, and to fly. They come in different strengths and efficiencies. Boosters cannot be equipped on Tank and Hover ACs, as these have built-in boosters.

In Armored Core: Nexus, players have to be cautious when equipping and using boosters because they now not only drain energy but produce heat too, which can hamper the performance of the player's AC if it overheats. The amount of heat produced from an AC's boosters is tied to the Generator's calorific value, so hotter boosters should be used with cooler running Generators with low calorific values.

Generator
Supplies power to the AC. Power is an important consideration in the Armored Core games - the generator can only generate energy at a certain rate, and if the AC uses energy at a faster rate, the charge held by the generator is depleted. If the energy produced by the generator is depleted past the generator's red zone it immediately shuts off all other high-energy dependent functions and recharges, leaving the AC very vulnerable. Recharging ACs cannot use their boosters or energy weaponry until the generator has completely recharged, and in battle up to a minute without weapons or mobility can end up costing a heavy price. The time it takes to recharge varies from generator to generator; also, the generator is still supporting the AC's necessary functions while charging, and these (particularly the radiator) slow the recharge rate. The quickest way to recharge, therefore, is to stand completely still and do nothing.

Radiator
ACs can get very hot, and when overheated their combat effectiveness is reduced. Radiators attempt to release this heat, with varying efficiency. Heat is produced by taking hits from various types of weaponry, by the external environment, and in Armored Core: Nexus by the AC's boosters.

From Armored Core to Silent Line: Armored Core, an overheated AC would incur damage until the temperature was lowered.

In Armored Core: Nexus the heat system was completely reworked. Now heat does not do instant damage to an AC, but when an AC becomes overheated the radiator begins sucking massive amounts of energy from the AC's generator to cool down the core. This can quickly deplete its energy supply and leave it vulnerable if the radiator is not very efficient. If the heat level cannot be brought down quick enough or goes too high too quickly, the AC will still take damage.

Non-Essential Parts
These parts can be left off if the player desires; however, an AC will have difficulty progressing far into the game without a weapon of some kind.

Inside(Armored Core 2 onward)
An internal compartment from which a variety of devices can be released, including bombs, mines, decoys and radar-jammers. In Armored Core 3 small rockets and napalm rockets were added to the selection. These rockets have no aiming trejectory in the HUD and needed to be fired blindly. These parts were located in the top rear of the core facing backwards in the Armored Core 2 series and in the shoulders facing forwards from Armored Core 3 onward.

Extension(Armored Core 2 onward)
Extensions come in pairs and are mounted on the sides of the shoulders. They are miscellaneous, usually non-offensive devices, and can be anything from extra boosters to stealth devices.

Extra boosters (with various functions)
Anti-missile systems
Relation missiles (extra missiles that fire simultaneously with missile launchers)
Shoulder energy shields
Emergency heat sinks (rapidly cools an AC)
Emergency energy units (rapidly recharges energy)
In Armored Core 3, several emergency energy units were sold - these were usually 3 uses, and would quickly refill the energy of an AC in about 5 seconds. Emergency heat sinks were also introduced that allowed a quick cooling burst to bleed off potentially damaging heat if an AC got too hot. In Armored Core 2, additional booster and relation missiles become available but in "Armored Core: Nexus" the radar jamming equipment was removed along with the radiator and ECM equipment.

Back Unit
There are two points on the back where weapons or devices may be mounted. These include:

Missile launchers
Rocket launchers
Guns (chain guns, slug guns, rail guns, pulse guns, etc)
Cannons (grenade launchers, laser cannons)
Orbit cannons (floating guns)
Radars
Extra ammunition supplies
Some weapons and devices take up both Back Unit slots.

Cannon-type weapons must be fired over the shoulder, so there is usually a delay in activating the weapon for it to unfold or align itself. Bipedal and Hovering ACs have insufficient stability to use a cannon-type weapon whilst standing or moving, so it is more common to see missile and rocket launchers on these ACs.

In earlier games AC pilots who unlocked the Human PLUS modifications or gained the black market Optional Part OP-INTENSIFY were able to deploy cannons while moving but such features have been removed from more recent games like Armored Core: Nexus, Nine Breaker and Last Raven, although in some of these the AI players appear to still have access to OP-INTENSIFY.

Arm Unit R
This is the right arm weapon, and for most ACs it is their primary offense. There are a large number of different weapons, including rifles, machine guns, handguns, bazookas, shotguns, grenade rifles, laser guns and various energy weapons.

In Armored Core 3, parrying blades are available - these are short-range blades used to counter a laserblade strike and deal heavy damage, however there is a significant lag time between when the trigger is pulled and when the blade activates.

The most powerful weapons in the games (with the possible exception of the WA-FINGER in Project Phantasma, Master of Arena and its later incarnations in Nexus, Nine Breaker, Formula Front and Last Raven) are the Karasawa series, named for one of the series' producers. Armored Core has the Karasawa, the Karasawa Mk. II in Armored Core 2, and Armored Core 3 saw the MWG Karasawa. In Armored Core: Nexus through Armored Core: Last Raven, this weapon is called the WH04HL-KRSW, but has been knocked off its pedestal by other more powerful weapons added in to the later games. In an attempt to make up for this fact, one is allowed to use two Karasawas from Nexus onward.

Arm Unit L
The left arm was traditionally used for melee weapons, typically the laserblade, which is a short-range blade of energy which can cause great damage to an opponent. One can also equip hand-held energy shields which can absorb damage from weapons and laserblades. Armored Core 3 introduces solid shields which used no energy. They could simply be activated at the beginning of a battle and would greatly reduce all frontal damage taken until they broke. They are banned from many tournaments.

As the series has progressed, a greater variety of weapons has appeared for the left arm. Armored Core 3 introduced a few ranged weapons, such as howitzers. Armored Core: Nexus produced a much larger selection of left arm weapons, including copies of various right arm weapons, although the reaction time to fire these is far slower when compared to weapons held by the right arm.

Optional Parts
These are parts which can be plugged into slots in the core to enhance the AC's performance. They have a variety of effects, such as increasing damage resistance to certain weapons, or increasing the generator capacity.

Different cores have different numbers of slots for optional parts, and generally more powerful optional parts cost more slots, while those only applied to certain situations are less slot-costly.

In Armored Core 3 and Silent Line: Armored Core a special unlockable Optional Part exists known as OP-INTENSIFY, or OP-I for short. This part, awarded to you upon your completion of Armored Core 3 's storyline, allows you to use new features on your AC like the Human PLUS enhancements of the previous AC games. The part automatically takes up every single Optional Part slot provided in your equipped Core so no other Optional Parts can be used while the OP-I is equipped. Replaying past missions and completing specific tasks unlocks new abilities and powers up your AC. These abilities are:

"Blade wave" projection
Enhanced energy blade range
Enhanced radar abilities
All radar abilities added regardless of equipment
Able to fire back cannons while moving on leg bases other then tanks and quadrupeds.
Enhanced normal cooling (No effect on Forced Cooling Stats)
Enhanced boosters
Enhanced missile interception
Enhanced turning abilities
Enhanced targeting abilities

The OP-INTENSIFY and Human PLUS were removed from later AC games like Nexus, Nine Breaker and Last Raven, yet enemies like Nexus' #1 Arena Raven Genobee still exhibited PLUS-like performance levels and abilities in combat.

The OP-INTENSIFY and Human PLUS caused a lot of controversy over its usage, as some will dispute the quality of a player(s) who might use it. The part was looked down upon by some in the community, citing that it was 'unfair' or 'cheating', though some veterans used PLUS and OP-INTENSIFY as well, and many believed that it was possible to use it without being cheap. The conflict and debate over these two functions raged until they were finally removed in Nexus.

In fan circles the term "PLOW" is often used to descibe ACs operating with PLUS or PLUS-like atributes. The term is a compound of "PLUS" and "Over Weight". The term dates back to the original Armored Core, where PLUS and the "Overweight" features originated.

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