A formation is a collection of specific units that receive special bonuses.

Note that formations differ from groups (multiple units selected at the same time which can be commanded as one). A formation is a special state applied to a group of compatible units. 

Formations are used for strategic military engagements, have distinct limits on the number and type of units that can enter them, and distinct advantages to doing so. This encourages use of small, tactical formations for specific purposes, more effective than a larger, unruly mob.

Bonus

BRIEF DESCRIPTION ::The attribute that is bonused.

This defines what attribues may be bonused.

Typically the following attributes could be affected:

Move.Speed
Health.Hitpoints
Health.Regen
Armour.Value
Vision.LOS
Attack.Accuracy
Attack.Damage
Attack.Speed
Attack.Range

BonusType

BRIEF DESCRIPTION:: The entity type that is bonused.

This defines what entities in the formation will receive the bonus. These are defined by the entity's Id properties: Id.Type or Id.Generic.

BonusValue

BRIEF DESCRIPTION:: The value of the bonus

This is the percentage of the bonus. If it is a value of .2 that gives a 20% bonus.

Penalty

BRIEF DESCRIPTION ::The attribute that is penalised.

This defines what attributes may be penalised.

Typically the following attributes could be affected:

Move.Speed
Health.Hitpoints
Health.Regen
Armour.Value
Vision.LOS
Attack.Accuracy
Attack.Damage
Attack.Speed
Attack.Range

PenaltyType

BRIEF DESCRIPTION:: The entity type that is penalised.

This defines what entities in the formation will receive the penalty. These are defined by the entities Id properties: Id.Type or Id.Generic.

PenaltyValue

BRIEF DESCRIPTION:: The value of the penalty.

This is the percentage of the bonus. If it is a value of .1 that gives a 10% penalty.

The penalty should always have less effect than the bonus. It's a give and a take situation that must give more than it takes, otherwise nobody will use the formation. We take in order to preserve balance and historical accuracy in military tactics.

Width

BRIEF DESCRIPTION ::The width of the formation.

Theoretically, we would not need this for attributes of formations, but we will need it for groups that do not use the Formation.Order attribute.

Required

BRIEF DESCRIPTION ::The number of units required to make this formation.

This specifies the minimun number of required units before it drops to the previous formation. See Prior for more details. 

Next

BRIEF DESCRIPTION ::Points to the tag of the next formation after the formation cap is reached.

In order to perserve the shape of the formations and their filling order, it is necessary to have a progression of formation 'shapes'. This attribute points to the next formation XML file that should be used if the number of entities exceeds the number of entity slots in the current formation.

Prior

BRIEF DESCRIPTION ::Points to the tag of the previous formation if the number of entities in the formation is not met.

As the number of entities decreases, the formation must change to compensate for the 'gaps'. This points to the previous formation which has the proper configuration for the smaller quantity of entities. If this attribute does not exist, then it it means the formation is disbanded if the requirements are not met.

Movement

BRIEF DESCRIPTION ::The group form it takes when they are moving to a waypoint.

When a formation is ordered to a waypoint, this attribute specifies what formation/group pattern they form when going to that destination. When they arrive at the waypoint, they revert back to their original formation.

Note: this only affects movement to a waypoint; the formation does not change when ordered to attack. It retains its formation while it advances to attack.

If this attribute is not specified, it retains its formation even in movement (such as testudo or phalanx).

Category

BRIEF DESCRIPTION ::The entity allowed at position.

This corresponds to ​Entity.Formation.Category. This specifies what entity may go in what position. 

Some positions may be filled by multiple entity categories. The precedence of what goes in what position is: lead=>melee=>ranged=>support. 

So if a ranged unit is in a slot that a melee unit can fit in, then it bumps it to another ranged position. If there is no position available the ranged unit gets bumped out of the formation or the formation goes to the Next formation where an open slot would be available.

Order

BRIEF DESCRIPTION ::Entity position fill order.

Order defines the fill order of the entities. The engine needs to check if the entity is allowed to partake in the formation, then it checks to see what Formation.Category it is, then it checks the positions to see if there is an available slot in this following order. If there is, it's added, if there isn't, it's not allowed to be added.

fl

BRIEF DESCRIPTION ::File, a row of entities.

fl stands for file. This specifies a row of entities.

rk

BRIEF DESCRIPTION ::Rank, a position (cell) in a file (row).

rk stands for rank. This specifies a slot in a row of entities.

Example:

<formation Tag="Form Box 2"
   bonus="stat.armour"
   bonustype="unitmelee"
   bonusval=".2"
   penalty="move.rate"
   penaltytype="unitmech,unitnonmech"
   penaltyval=".1"
   width="5"
   required="10"
   next="Form Box 3"
   prior="Form Box 1"
   movement="Group Line"

   <fl category="melee">
     <rk order="1"></rk>
     <rk order="10"></rk>
     <rk order="2"></rk>
     <rk order="11"></rk>
     <rk order="3"></rk>
   </fl>
   <fl category="melee">
     <rk order="12"></rk>
     <rk category="melee, ranged" order="18"></rk>
     <rk category="melee, ranged" order="22"></rk>
     <rk category="melee, ranged" order="19"></rk>
     <rk order="13"></rk>
   </fl>
   <fl category="melee">
     <rk order="4"></rk>
     <rk category="melee, ranged" order="23"></rk>
     <rk category="support, lead, ranged" order="5"></rk>
     <rk category="melee, ranged" order="24"></rk>
     <rk order="6"></rk>
   </fl>
   <fl category="melee">
     <rk order="14"></rk>
     <rk category="melee, ranged" order="20"></rk>
     <rk category="melee, ranged" order="25"></rk>
     <rk category="melee, ranged" order="21"></rk>
     <rk order="15"></rk>
   </fl>
   <fl category="melee">
     <rk order="7"></rk>
     <rk order="16"></rk>
     <rk order="8"></rk>
     <rk order="17"></rk>
     <rk order="9"></rk>
   </fl>
</formation>

_FORMATIONS_

​Historian Article: Basic Formations and Movements

1. FORMATION CHARACTERISTICS

SPEED
* Formations can only move at the speed (MR) of the slowest unit within them.

MOVEMENT INTERRUPTION
* Moving formations, commanded over distance to go from point-to-point, are incapable of attack while moving (unless it's a special unit trait - Parthian cavalry archers, elephants, chariots).

IDLE ORIENTATION
* Idle formations will orientate themselves with the vector from their prior waypoint

ATTACK
* The formation's Attack command targets an area, and not a specific unit.  The units in a formation will then advance (if needed and if allowed by their AI stance) and attack according to their optimal RPS dynamics vs. their enemies in that area.  

CONTROL
* Most Formations can be constituted without being placed under control group numbers (Ctrl+...num). 
* Units can be added to formation by using a GUI 'join' command.

FORMATION POSITIONS
* Melee - Foot Hackers.
* Protected - Units that should be protected - Healers, Female Citizens, etc.
* Ranged - Ranged Units.
* Lead - Hero units (and later in Part II, morale units)

2. FORMATION TYPES

Graphical Representation

BOX

Minimum Number Required: 9
Available to Classes: UnitMechanical, UnitMilitary, UnitSupport, Hero
Bonus: Melee Armour.
Debonus: Movement Rate.
Special: N/A.
Explanation: The Box Formation is typically used to surround units within it that are weaker, more vulnerable, or of high value to the player.  A formation with a defensive posture, that is good to use as a 'last stand'.

CLOSED COLUMN

Minimum Number Required: 9
Available to Classes: UnitMilitary, UnitSupport, Hero
Bonus: Movement Rate.
Debonus: Melee Armour.
Special: Width of 3 max
Explanation:
- Basic formation for rapid unit distance movement.
- The stongest units assemble to the front of the column.

CLOSED LINE

Minimum Number Required: 9
Available to Classes: UnitMechanical, UnitMilitary, Hero
FormationCategory Positions
* Melee = front.
* Mobile = front.
* Protected = back.
* Ranged = middle/back.
Bonus: Pierce Attack, Melee Attack.
Debonus: Movement Rate, Pierce Armour.
Special: Depth of 3 max, Closely Packed Together.
Explanation:
- The basic battle line.
- Strongest units form to the front rank; if mixed hacker and ranged, melee to the front.

OPEN COLUMN

Bonus: Pierce Armour.
Debonus: Melee Armour.
Special: Width of 3 max, Loose formation.
Explanation:
- Like closed column, but staggered for protection against ranged attack and splash damage

OPEN LINE

Bonus: Pierce Armour, Crush Armour.
Debonus: Movement Rate, Melee Armour.
Special: Depth of 3 max, Loose formation.
Explanation:
- Like closed line, but staggered for protection against ranged attack and splash damage

SKIRMISH

Minimum Number Required: 9
Available to Classes: UnitRanged
Bonus: Movement Rate, Attack Rate, LOS.
Debonus: Melee Armour.
Special: Evades Enemy, max depth of 2 (terrain permitting).
Explanation:
- Resembles an Open Line
- Limited to ranged units
- Ideally, these guys will run up to within their range of the enemy, fire their weapon, then retreat then continue the cycle.

FLYING WEDGE

Minimum Number Required: 9.
Available to Classes: UnitMechanical, UnitMilitary, UnitMedic, Hero
Bonus: Movement Rate, Melee Attack.
Debonus: Pierce Armour.
Special:
- Semi-unique to the 'barbarous' Celts and Iberians.
- Protected go to the back middle.
Explanation:
- A break-through formation, mainly used by hackers.

TESTUDO

Minimum Number Required: 9.
Available to Classes: FootSword
Bonus: Armour
Debonus: Movement Rate.
Special:
- Unique To Romans.
Explanation:
- The turtle formation.
- Unable to attack while in this formation.
- Ultra high resistance to attack.
- Cannot enter Flank.
- Retains its formation in movement, and very slow

PHALANX

Minimum Number Required: 12
Available to Classes: FootSpearman
Bonus: Armour
Debonus: Movement Rate.
Special: Unique To Hellenes.
Explanation:
- The standard phalanx of the Greek/Macedonian era
- Retains its formation in movement, and slow