AA combat formula

[alexman]

• The real strength of each AA unit is 1/10th of the value shown in the editor. So Flak has a strength of 0.2.
• Each AA unit in the tile being bombarded takes a shot against the defense of the bombarding air unit. The chance of shooting down the air unit is A/(A+D), as with all other forms of combat in Civ3. Remember, A is 10 times less than what is in the editor for the AA unit.
• The maximum number of AA units that are given a chance to shoot down the plane is 4. Any AA units above 4 are ignored.

So, for example, if you want the formula for the probability of N units with a strength of A shooting down a plane with defense of D, here it is:

1 - (D / (D+A))^min(N,4)

[Jaybe]

alexman, basically how did you determine this (code examination, experimentation, ...)??

[alexman]

Experiment. Debug mode with reveal map. Gave the AI 320 bombers all within range of my only city, and a number of flak units to myself. Contacted AI and declared war. After his turn, I hit F3 to see his remaining bombers. Change stats of bombers and flak, and repeat. It doesn't take long if you switch off all animations.

[Arrian]

Thanks, alexman.

-Arrian

[Capt Dizle]

This is one of my pet peeves, that we have to depend on folks like alexman to tell us how the game works. It ought to be revealed by Firaxis. Another case of developer's ego.

Great work. Kudos.

[Catt]

Nice job, alexman

Catt

[asleepathewheel]

cool

[Cookie Monster]

So stationing more than 4 AA units in a city is a waste?

[alexman]

Unless some of them die during the bombing.

[MattPilot]

help me out here please, ..

A = attack value

D = Defense value (modifiers applied? say stock defense of 6 + 50% city + 50% fortified = Defense of 12 - did i get that right ?)


So plugging in the numbers for the flak, with above defense modifiers & assuming 20 bombers, i'd get:

1 - (12 / (12 + 0.2))^min(20,4)

1 - (0.9836)^min(20,4)

now, i'm stuck on the exponent part. help me out with the 'min' part & why there are 2 numbers posing as an 'ordered pair' ?
How would i go about solving that?

[vmxa1]

Well now I know why my AA defenses were stinking the place up.

I agree with jimmytrick, this type of stuff should be documented. I don't mind if they had put it in the strat guide and made us pay, but it should be published. I understand it cost money to publish manuals, but what about readme docs. They could be hosted by the game sites and not cost them anything. The work is probably already done, as this information must be available to the devs.

[alexman]

D is the defense value of the bombarding air unit (2 for a bomber). No modifiers apply. A is the AA strength of the AA unit (0.2 for flak). N is the number of AA units, not the number of air units.

min(N,4) = N, if N less or equal to 4
min(N,4) = 4, if N greater than 4

Hope this helps...

[Risa]

Splendid work!

[asleepathewheel]

Originally posted by jimmytrick
This is one of my pet peeves, that we have to depend on folks like alexman to tell us how the game works. It ought to be revealed by Firaxis. Another case of developer's ego.

I agree that it should be revealed, but then would Alexman get as much enjoyment out of the game?

Firaxis has always had this problem, even when BR was running the show, just look at the pod bloomings or pollution or whatever it was. Years, IIRC, before someone dissected that mystery. I would throw up another recent strat game (insert joke here), MoO3 as an example of the players having no clue as to the mechanics which greatly sabotaged the game's success (there were problems far beyond that though )

[MattPilot]

ah, oki thanks alexman - i feel stupid now that i asked

anyway, if i did my math right, then a bomber with a defense value of 2, would have the following chance to get shot down:

(**edit see alexman's data**)