Garrison¶

Mechanics related to garrisoning units in buildings or siege units.

Number of projectiles¶

How many projectiles a building fires depends on two variables, the damage per second value of the building and the (pierce) damage per second of each garrisoned unit. The amount of arrows added by a unit can be derived from this formula:

    additional_arrows = sum(unit_dps_pierce) / building_dps

unit_dps_pierce is calculated by dividing a unit’s pierce attack value by its reload speed. building_dps is obtained in the same way, by dividing the building’s attack value by its reload speed. Units doing melee damage do not increase the number of arrows or projectiles. However, for villagers unit_dps_pierce is a fixed value of 2.5. Researching the Teuton unique technology Crenellations has a similar effect by setting unit_dps_pierce to 2.5 for every unit in the infantry armor class.

Bombard towers have even stricter rules in that only gunpowder units can increase the projectile count. The calculation of building_dps is also done slightly different. For the first additional projectile sum(unit_dps_pierce) is divided by (building_dps * 2) which effectively doubles the amount of required units for an additional shot. For the second and third cannon ball the standard formula is used again.

Pseudocode

    remaining_unit_dps = sum(unit_dps_pierce) - (building_dps * 2);

    if(remaining_unit_dps >= 0) {
        additional_arrows = 1 + (remaining_unit_dps / building_dps);
    }
    else {
        additional_arrows = 0;
    }

The result additional_arrows is floored and added to the default arrow count of the building. A table with the default projectile counts is shown below.

Building	Default Arrow Count	Default Attack	Maximum Arrow Count
Town Center	0	5	10
Castle	5	11	20
Tower	1	5/7/8*	5
Bombard Tower	1	120**	4

* Damage of Watch Tower/Guard Tower/Keep

** Calculation is different; see pseudocode above

Increasing the default attack damage of buildings by researching technologies also affects building_dps.

Example¶

The Elite Janissary has a pierce attack value of 22 and a reload speed of 3.45 (The Conqueror’s). With these values we can calculate unit_dps_pierce.

unit_dps_pierce = 22 / 3.45 = 6.37

Now that we know unit_dps_pierce, the amount of additional projectiles for each building can be obtained.

Town Center

    building_dps = 5 / 2.03 = 2.46

    additional_arrows = 6.37 / 2.46 = 2.58

Castle

    building_dps = 11 / 2.03 = 5.41

    additional_arrows = 6.37 / 5.41 = 1.17

Keep

    building_dps = 8 / 2.03 = 3.94

    additional_arrows = 6.37 / 3.94 = 1.61

Bombard Tower

(1st additional projectile)
    building_dps = (120 / 6) * 2 = 40
(Other additional projectile)
    building_dps = (120 / 6)     = 20

(1st additional projectile)
    additional_arrows = 6.37 / 40 = 0.155
(Other additional projectile)
    additional_arrows = 6.37 / 20 = 0.31

7 Elite Janissaries are needed to make the bombard tower fire one additional projectile. Two additional cannon balls are only achievable with 10 Elite Janissaries garrisoned in a bombard tower.

Weird AoE2 Quirks¶

Only units that do pierce damage can increase the number of projectiles fired by a building. Units that fire projectiles dealing melee damage - like Gbetos, Throwing Axemen and Mamelukes - will have no effect on the arrow count.
For the Cho Ko Nu unit_dps_pierce does not use the pierce attack value of the first arrow fired. Instead it only takes the damage the last arrow does into consideration. Because this arrow only does 3 pierce damage, the number of projectiles added to a building’s attack is fairly low.