AutomatedTeller
Frequent poster
Mostly, siege warfare is well-understood, but there are some things that don’t show up in the war academy articles (how flanking works) and some things I had to figure out on my own (Drill and how cannon, et al effect cities with castles)
Several articles are used and referenced in this guide.
First, of course, is the war academy article Combat Explained, by sermirami.
Second is a post on flanking http://forums.civfanatics.com/showpost.php?p=7509341&postcount=14 by DanF5771.
The basics:
Siege units are military units that have 2 purposes - reduce city defenses and damage unit stacks via collateral damage. Siege units are catapults, trebuchets, cannons, artillery and mobile artillery.
Siege units are immune to collateral damage from other siege units, but horse units can inflict similar damage via flanking. Collateral damage is non-lethal, while the damage from flanking can be.
Also, non-siege units that inflict collateral damage (tanks, bombers, Cho-ko-nu) do inflict damage on siege units.
Siege cannot attack from the sea. They can attack across rivers.
Reducing city defenses:
All siege can reduce city defense and with the accuracy promotion, the amount goes up by 8%.
Walls and Castles
Along with raising the defense of the city to 50/100%, walls and castles both reduce the amount of damage catapults and trebuchets do on the city defenses - walls by 50%, castles by 25%. So, a catapult will do 8% vs. a regular town, 4% vs. a town with walls and 2% vs a town with castles.
Cannons and artillery do full damage vs. walls/castles. However, in the case where the cultural defense of a city is less than the castle/walls, the amount of defensive reduction that a gunpowder unit sees is proportional to the overall change. For example: A cannon bombards a city with 60% culture defense and a castle. It does 12% damage to the defense, making it 88%. The defense seen by a gunpowder unit is also reduced by 12% - but 12% of the 60, or ~7%, to 53%.
Other ways to reduce city defenses:
1) Naval units. Frigates, ship-of-the-line, destroyers, battleships, stealth destroyers and missile cruisers can all reduce city defenses, ranging from 8% for a frigate to 20% for a battleship or missile cruiser. Naval units cannot take accuracy, but they all ignore walls and castles like gunpowder seige do. Of course, they can only bombard coastal cities.
2) Air units. Fighters and bombers (not airships or gunships) can reduce city
defenses, by 8-20%
3) Cities in revolt have no defense. This can happen from cultural pressure or from a city revolt mission from a spy.
I believe that city defense recovers at 2% a turn, but I don’t know. Anyone?
Collateral damage:
The war academy article on combat describes how collateral damage works and I won’t repeat it in depth, but it doesn’t address Drill promotions. In summary, collateral damage is 1/2 normal and is based on the relative strengths of the siege unit and the unit receiving the damage.
Barrage promos are the only promos that can change this ratio. Drill II-IV reduce the total damage given by 20% each (this isn’t a change to the ratio, it’s a change to the actual damage done and is thus a lot more effective)
For catapult vs. archer, the damage done by collateral is as below:
This assumes that the Drill calculation is a ceiling calc, as opposed to a Floor or a Round. I don’t know which it is.
Drill or CG for defenders?
Take the case of a mace with CR1 attacking a LB in a city that has been stripped of defense. Assume that the LB has taken one round of collateral damage. Is it better for the LB to have Drill II or CG II?
A Barrage 1 cat does 10 damage to an LB, 8 to a Drill II LB.
For a non-protective Civ (2 promos to get drill), CG is the better promotion until you take 3 rounds of collateral. For a protective Civ, however (start with CG1 and Drill I), Drill is the better promo (for units that get collateral)
The table below refers to the number of HP left after the given rounds of collateral and the 2 promos. For a non-protective civ, CG2 and Drill II requires 2 promos. For a protective Civ, it requires 1 promo
Flanking damage:
Flanking allows for similar affects on siege that collateral damage from siege inflicts on non-siege units. Flanking is done by mounted units (or gunships late in the game). It can’t be done by any other units – air, armor, naval.
There is a very good detail on flanking here.
In short: Units can flank 6-8 units. Units can flank siege of a similar or earlier era. The siege unit has no say on the damage it takes – it’s all dependent on the unit doing the flanking and the unit it attacked. A siege unit can escape flanking (based on the strength ratio of the attacker/defender, modified by the withdrawal %). The unit flanks siege units that don’t escape, up to the limit. Damage is done based on the damage per round inflicted on the defender.
For example:
- Combat II HA vs. combat 1 spear: HA have a 20% withdraw rate. Assuming the HA wins or withdraws, each cat's chance to escape flanking is 43% (8.4/(8.4+7.2)*.8) and each cat that takes damage will take 18 points.
- Combat II Numidian Cav vs Combat 1 spear: Each cat's chance to escape is 36% (6.4/(6.4+6)*.7 and each cat that takes damage will take 19 points
- Combat II HA vs. catapult: Each cat being flanked has a 25% escape chance and takes 28 points of damage.
Best unit to protect cats (available early, of course) is the elephant.
Best way to inflict lots of flanking damage on cats protected by elephants with HA - flanking 2. the damage flanking II HA do is a point less, but the escape is a lot lower, and the chance of withdrawal is a lot higher.
An implication is that if you are facing a large stack with a lot of siege, you are better off hitting the stack with siege (to create collateral damage) before horses, because flanking is more effective against damaged units.
I hope this is helpful. Sorry for the formatting issues.
Several articles are used and referenced in this guide.
First, of course, is the war academy article Combat Explained, by sermirami.
Second is a post on flanking http://forums.civfanatics.com/showpost.php?p=7509341&postcount=14 by DanF5771.
The basics:
Siege units are military units that have 2 purposes - reduce city defenses and damage unit stacks via collateral damage. Siege units are catapults, trebuchets, cannons, artillery and mobile artillery.
Siege units are immune to collateral damage from other siege units, but horse units can inflict similar damage via flanking. Collateral damage is non-lethal, while the damage from flanking can be.
Also, non-siege units that inflict collateral damage (tanks, bombers, Cho-ko-nu) do inflict damage on siege units.
Siege cannot attack from the sea. They can attack across rivers.
Reducing city defenses:
All siege can reduce city defense and with the accuracy promotion, the amount goes up by 8%.
Walls and Castles
Along with raising the defense of the city to 50/100%, walls and castles both reduce the amount of damage catapults and trebuchets do on the city defenses - walls by 50%, castles by 25%. So, a catapult will do 8% vs. a regular town, 4% vs. a town with walls and 2% vs a town with castles.
Cannons and artillery do full damage vs. walls/castles. However, in the case where the cultural defense of a city is less than the castle/walls, the amount of defensive reduction that a gunpowder unit sees is proportional to the overall change. For example: A cannon bombards a city with 60% culture defense and a castle. It does 12% damage to the defense, making it 88%. The defense seen by a gunpowder unit is also reduced by 12% - but 12% of the 60, or ~7%, to 53%.
Other ways to reduce city defenses:
1) Naval units. Frigates, ship-of-the-line, destroyers, battleships, stealth destroyers and missile cruisers can all reduce city defenses, ranging from 8% for a frigate to 20% for a battleship or missile cruiser. Naval units cannot take accuracy, but they all ignore walls and castles like gunpowder seige do. Of course, they can only bombard coastal cities.
2) Air units. Fighters and bombers (not airships or gunships) can reduce city
defenses, by 8-20%
3) Cities in revolt have no defense. This can happen from cultural pressure or from a city revolt mission from a spy.
I believe that city defense recovers at 2% a turn, but I don’t know. Anyone?
Collateral damage:
The war academy article on combat describes how collateral damage works and I won’t repeat it in depth, but it doesn’t address Drill promotions. In summary, collateral damage is 1/2 normal and is based on the relative strengths of the siege unit and the unit receiving the damage.
Barrage promos are the only promos that can change this ratio. Drill II-IV reduce the total damage given by 20% each (this isn’t a change to the ratio, it’s a change to the actual damage done and is thus a lot more effective)
For catapult vs. archer, the damage done by collateral is as below:
Code:
[FONT="Courier New"]
None BI BII BIII
No Drill 12 14 15 17
Drill 2 10 12 12 14
Drill 3 8 9 9 11
Drill 4 5 6 6 7
[/FONT]This assumes that the Drill calculation is a ceiling calc, as opposed to a Floor or a Round. I don’t know which it is.
Drill or CG for defenders?
Take the case of a mace with CR1 attacking a LB in a city that has been stripped of defense. Assume that the LB has taken one round of collateral damage. Is it better for the LB to have Drill II or CG II?
A Barrage 1 cat does 10 damage to an LB, 8 to a Drill II LB.
For a non-protective Civ (2 promos to get drill), CG is the better promotion until you take 3 rounds of collateral. For a protective Civ, however (start with CG1 and Drill I), Drill is the better promo (for units that get collateral)
The table below refers to the number of HP left after the given rounds of collateral and the 2 promos. For a non-protective civ, CG2 and Drill II requires 2 promos. For a protective Civ, it requires 1 promo
Code:
Non-protective
CG2 Odds Drill II Odds
1 90 28% 92 36%
2 80 35% 84 53%
3 70 67% 76 60%
4 60 85% 68 84%
5 50 95% 60 89%
Protective
CG2 Odds Drill II Odds
1 90 19% 92 18%
2 80 25% 84 33%
3 70 56% 76 50%
4 60 76% 68 57%
5 50 91% 60 84%Flanking allows for similar affects on siege that collateral damage from siege inflicts on non-siege units. Flanking is done by mounted units (or gunships late in the game). It can’t be done by any other units – air, armor, naval.
There is a very good detail on flanking here.
In short: Units can flank 6-8 units. Units can flank siege of a similar or earlier era. The siege unit has no say on the damage it takes – it’s all dependent on the unit doing the flanking and the unit it attacked. A siege unit can escape flanking (based on the strength ratio of the attacker/defender, modified by the withdrawal %). The unit flanks siege units that don’t escape, up to the limit. Damage is done based on the damage per round inflicted on the defender.
For example:
- Combat II HA vs. combat 1 spear: HA have a 20% withdraw rate. Assuming the HA wins or withdraws, each cat's chance to escape flanking is 43% (8.4/(8.4+7.2)*.8) and each cat that takes damage will take 18 points.
- Combat II Numidian Cav vs Combat 1 spear: Each cat's chance to escape is 36% (6.4/(6.4+6)*.7 and each cat that takes damage will take 19 points
- Combat II HA vs. catapult: Each cat being flanked has a 25% escape chance and takes 28 points of damage.
Best unit to protect cats (available early, of course) is the elephant.
Best way to inflict lots of flanking damage on cats protected by elephants with HA - flanking 2. the damage flanking II HA do is a point less, but the escape is a lot lower, and the chance of withdrawal is a lot higher.
An implication is that if you are facing a large stack with a lot of siege, you are better off hitting the stack with siege (to create collateral damage) before horses, because flanking is more effective against damaged units.
I hope this is helpful. Sorry for the formatting issues.
The first one is correct, obviously: siege units are imune to collateral damage of other siege units. They suffer collateral damage of other sources: Chinese UU, bombers, Tanks with barrage promos pre BtS 3.13 ...
