Draginol

Join Date 03/2001

+137

Balancing Defenses

A tale of how defenses work.

In Galactic Civilizations II, you have beam weapons, missile weapons, and mass-driver weapons.

Against these weapons are corresponding defenses -- shields, anti-missile defenses, and armor. Defenses in a different area do provide some benefit -- they are the square root of their value.

So if a fighter with Blasters (beam) of 3 attacks a ship with 0 shields, 4 armor, and 0 point defense then the battle goes something like this:

Fighter rolls beteween a 0 and a 3 and the defender rolls between a 0 and a 2 (square root of 4).

The significance of this is that if you pick the wrong defense, you take quite a pounding on your ship. This means that defenses should cost quite a bit less and be somewhat easier to obtain (otherwise you might as well just crank out the strongest offensive ships possible).

Balancing this out is tough. We want different defenses to have different advantages over time. Here's what we came up with:

		Size(Tiny)	Size(Large)	Cost	Power	FighterValue	CapitalShipValue	FighterPower	CapitalPower	Winner
b	Deflectors2	9	13	15	1	9.70	21.33	1.32	4.00
md	Titanium2	6	13	20	1	15.61	14.79	1.94	3.85	Armor
m	Chaffe2	11	15	8	1	11.96	27.78	1.07	3.33
b	Shields	9	13	20	2	14.18	29.59	2.61	7.69
md	Duranthium	8	12	30	2	11.90	23.15	2.93	8.33	Missile Defense
m	ECM2	9	13	10	2	28.36	59.17	2.61	7.69
b	Barriers	7	9	20	3	41.32	103.81	5.45	17.65
md	TriStrontium2	7	11	20	4	46.30	82.64	6.67	18.18	Shields
md	Superior Duranthium	6	8	50	4	30.61	71.11	8.57	26.67
b	Subspace Rebounder	7	9	60	5	22.96	57.67	9.09	29.41
m	Point Defense	9	11	30	4	21.63	60.47	5.58	19.05
md	Kanvium2	6	8	25	5	76.53	177.78	10.71	33.33
b	Barriers 3	5	7	25	3	68.05	142.01	7.83	23.08	Armor
m	PD Combo2	6	8	40	5	47.83	111.11	10.71	33.33
md	Duralthene	8	11	20	7	68.33	158.73	10.71	33.33
m	Droid Sentries	5	7	38	7	76.94	218.00	15.67	53.85	Missile Defense
b	Adv Force Fields	6	8	25	6	91.84	213.33	12.86	40.00
md	Adamantium	6	8	25	7	107.14	248.89	15.00	46.67
b	Invulnerabilty Field	5	7	30	7	132.33	276.13	18.26	53.85	Shields
m	Droid Sentries3	4	6	45	7	98.20	257.12	19.27	63.64
b	Ultimate Invulnerability	3	5	40	8	228.62	400.00	29.63	80.00
m	Aereon Missile Defense	4	5	60	11	122.37	366.67	31.13	110.00	Tie
md	Zero-Point Armor	3	5	45	10	220.20	444.44	34.48	100.00

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The numbers are hard to see, unless you select them by dragging on the screen. And the actual numbers don't say too much to me, I have not looked into combat yet. How do you get to the "value"listed?

However, your description of the defense rolls leads to a question.
Do you add the square roots of the different area defenses? Or do you add them first and then take the square root.
i.e. a ship with 4/4/4 defense, does it have a roll of 0-8 (4+2+2) or 0-7 (4+sqrt(8)) ?

And the defensive fire of 1/2 the defense value (if that is greater than the offensive) from GC1 is completely gone ?

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Also want to ask does size make a difference? Small vs Tiny. Large vs Huge ?

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Shogun, the hull size doesn't matter except for its stats and logistics requirements. Hull size determines the base number of hit points, the base amount of space available for modules, and the number of logistics points a ship costs to add it to a fleet. There's also a cost for each hull size, but that doesn't affect combat once the ship is built.

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So if you have multiple weapons of different types, does only the most powerful (absolute), the most useful (most powerful relative to defenses), all of them, or a random one get used for the calculation?

That is, is it worth it to put multiple weapons on a ship, or a waste of space and cash?

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Popup Target, I think the hull size DOES matter, as these defense modules take more space if you put them in larger size hulls... It is logical if you think it through: you need more armor / shield / chaff to defend a larger ship.
And I think I saw this mentioned by the devs somewhere, and it matches the table above.

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Sorry, I wasn't clear enough, that is exactly what I meant by "space available for modules." I was lumping weapons and defenses (and engines too) into modules, even though "modules" is just one tab. Should have said "space available for components." which also includes the fact that some components vary in size based on the hull they're put in. I meant that if a medium ship with 4 attack and 4 defense meets a tiny ship that manages to have the same stats (attack/defense/hitpoints), then the battle will be a tossup, with a slight advantage to whoever shot first.

Ulmont, I suspect that multiple weapons on a ship is still beneficial, but unless you hit a ship that is all one type of defense (and the type that is correct for your weapon type), you're better off making ships with only one weapon type (though I do like mixing weapon types within a fleet). The reason is, as near as I can tell, each weapon type has to shoot through the defenses independantly. By having two weapon types, that means all the ships defenses get to activate twice.

Here's an example: Consider a ship with 8 Beam attack attacking a ship with 4 beam defense, 4 armor defense, giving it an effective defense of 6 (I think).

So, the damage done will be equal to max(rnd(9)-rnd(7),0), or 1.89 points of damage on the average.

Now, if the attacker had 4 points of beam and 4 points of mass drivers, the defender still has an effective defense of 6, but now the damage done will be equal to max(rnd(4)-rnd(6),0)+max(rnd(4)+rnd(6),0), or 1.14 points of damage on the average.

Even if there's no defense, there's no difference in the average damage , but the bell curve drops off faster with two seperate weapons, so you're more likely to see average damage.

Now, one would think that "yeah, but if I'm hitting him with two different weapons, I'm going to tear him apart unless he has both types of defenses. Let's run some more numbers.

Assume a ship with 9 points of shields, and you're attacking with a ship with an attack of 12. With it all in beam weapons, you'll do 2.77 points of damage per combat turn on the average. With it all in missiles, you'll do 4.69 points of damage per comat turn on the average. Definitely better. So, where would you be with a 50/50 split between beam/missile weapons? You'd think it would be better than the pure beam, but it comes in at 2.66, even worse than the pure beam. On the other hand, if you got lucky and had missiles and mass drivers, you'd be doing 3.71 per turn on average. Nice idea, but now you're counting on getting lucky twice. The odds of picking one weapon that the opponent doesn't have the right defense for is higher than picking two weapons, and the payoff is bigger.

Just for the fun of it, let's compare a ship with 6 points of one type of defense to one with 2 points of defense against each type versus a ship mounting equal amounts of all three types of weapons.

The ship with 6 points of defense is going to have a defense of 6 against the one type that it's optimal against, and 2, 2.45, or 3 (depending on how they round it, I'm betting on 2, but using 3 in all calculations below unless otherwise mentioned) against the other two types of weapons. The ship with the split defenses will have a defense of 4 against all attacks.

Against a small attack, 2 of each, the single 6 defense ship will take an average of 0.86 damage per round of attacks, compared to 0.80 damage per round of attacks for the balanced defensive ship.

Against an attack of 6 each, the single 6 defense ship takes an average of 4.857 to the balanced ship's 4.71

So, playing around with the numbers, if a 6 defense of the wrong type rounds up to a 3, that ship is as effective as a balanced defensive ship if it's being attacked by ships with a 6 attack, 40% of whom have the weapon that defense counters best. As the damage proportion increasees, the percentage to achieve parity increases. As the total sum of the defense goes up, the percentage also goes up. If we assume that the devs will round the square root of 6 down to 2, the percentage goes up to right 59% of the time to reach parity.

So, in the final analysis, splitting up weapon types on a single ship bad, full stop. Splitting up defense types on a single ship good unless you're fighting a very static enemy.

How's that for taking a tangent and running with it?

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Well thanks for answering my question. And a big round of applause for that last post

totally answers all questions I had about it

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Popup Target, good analysis and useful examples !
One thing that you have not taken into account though is the effort needed to reach the levels of attack / defense, which is an item of game balancing... If it costs as much research to reach level 8 in beams as it does to get to level 4 twice in two weapon types, I agree with your analysis. However, if it ends up costing MORE the further you specialize, this will of course affect the calculations. Optimizing to get your best ships also involves WHEN you can get them, not only based on build costs but also on TECH costs.
I hope the developers will take all this into account, and ensure that for defense it will cost more space (and maybe credits), but less research to have a 2/2/2 defense than a 6/0/0; similarly an 8 weapon should cost more in research, but less in space (and maybe credits) than having two level 4 weapons.
Of course, the research cost is a one-time investment.

I think with the right game-tweaking this can remain an interesting dillemma, one not easily caught in a simple formula of "focus offense; split defense". And as Draginol said, they "want different defenses to have different advantages over time", everything should be viewed in the context of the general tech level of all involved parties.

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I suspect that it will be at least as easy to build a 6/0/0 ship as a 2/2/2 ship, if not easier. Remember that you're not comparing a single component with three, but any mix of components of the same category to a mix of components of different categories.

If you have room for three components and one of those provides a value of 2, then as long as it isn't above average size of those three components, then you can stick three of them in there, reaching 6/0/0. At this point, you haven't had to research the other two branches of components at all.

As for the shifting balance, I definitely agree that we need to adapt to different weapons/defenses being ascendant, but I honestly can't see a time where it will ever be good to mix attack types on a single ship. Mixing defense types is a totally different story, however. There, I can definitely see times it would be advantageous to focus on a single defense, but that may not be my normal pattern. On the other hand, even if I'm pushing out ships with a single weapon type, you can bet that I'll be spreading my research into other weapon types, so that if someone starts coming at me with ships that only have defense against the weapon I"m using, I can switch off easily.

So, there's still advantages to going deep in the tech tree. For the same research that you could get a 2/2/2 defensive ship, you could probably hit 8/0/0 or 9/0/0, which would be better against a static enemy, and might even hold it's own against adaptive enemies. Similarly, wide paths in weapons makes it easier to adapt to weaknesses in the enemy defenses, but narrow paths just let you hit harder, and hope you don't waste a lot of that firepower into the matching defenses.

The analysis I posted was really more of a "I've got techs X, Y, and Z, what's the best ship design I could make" type question rather than "Should I focus research into a narrow field, or try to pick up the low-lying fruit in all the fields" and I'm not up for that analysis at the moment

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The math may say split your defense, but the research time and space requirements say to not to. The space requirements for a defense are horrible. You wouldn't be able to build a 2/2/2 defense ship until you are pretty high up in each defense tree. If you are lucky, you can build a dual defense ship. Is that truly better then single defense ship? The single defense ship will be able to more easily fit in twice the defense rating, right? So the economics of ship building and research favors specialization as well, doesn't it?

Splitting a weapon? Never! Concentrating on one weapon lets you pack in more of that weapon. More weapons on ship, and quicker to the next layer of better weapons of that type, right?

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I usually find myself at a point where I'm placing one weapon and two defenses fairly early on in the game, usually starting with 4 attack and 4 defense on a small hull, and those are the first ships I make in any significant quantity, so I don't consider the difficulty in fitting two defenses on a ship a major factor.

I also don't bother with tiny hulls, there I think you'd have to be fairly well along in the game before split defenses were feasable.

As for splitting my research, I agree, and even mentioned that in passing. However, there's a penalty in overly specializing in a single weapon/defense tech line as well, so even if the split defenses weren't beneficial, I'd still be researching different tech paths. When I don't, the bit of any war immediately following the AI adapting to my current ship designs is usually quite painful until I research the right weapons and defenses to adapt to the AIs new ships. It's painful enough waiting until the ships start rolling off the production line, but getting stuck waiting on research before you can do that as well?

As for your last comment, are you saying you would never split weapons on a ship, or never split weapons research? If the former, I agree wholeheartedly, if the latter, I have to disagree there as well. The AI usually (but not always) adapts to your ship designs. If I sit with a single weapon type too long, I'm soon facing ships where the corresponding defense makes up the bulk of the defenses the ship has, and I'm getting taken to the cleaners by an AI that by all rights I should be beating. Improvements in the AI will only intensify this factor. On the other hand, if the AI seems to be stuck using the same wrong defenses (which I have seen at times), then by all means dig deep in that one weapons branch, just be ready if it gets unstuck or someone with the right defenses joins in.

Just realized one other reason that the split research doesn't impact me as much as it might impact people with a different playing style. I'm the tech leader, period. Oh, sure, for the first few years, I may not be outresearching the rest of the galaxy put together, but it's only a matter of time, and even then, I've probably traded for any tech that any of the AI players get (except medium hulls, they're very protective of that one). Those 4/4 ships I mentioned? I'm usually doing that before researching ANY military techs on my own. The AIs get very stingy with the higher level military techs, but depending on relations, you can usually get second generation (mass drivers, harpoons, etc) military techs out of the AI with suitable non-military techs. Sure, you'll be trading a tech for one that took a third as much research to get, but you're trading it to several AI players, so it all works out in the end.

Besides, some techs are just to good to keep to yourself. Nothing ensures a galaxy full of war quite like selling the "Alliance" tech to everyone in it, even if you're only getting 100BC for it from the poor races

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Er...

I'm playing out full games before any single 4 weaponry or medium hulls are in use. Well, the AI might have rolled off one or two such medium hull beasts at the end of my games. But it usually has those die against my starbases.

And that's with me being the overall tech leader.

I do split my weapon research. But from my games, what I see is that I only need 2. So I can completely neglect a third weapon branch. I find the AI does not adapt to my designs, and I roll of lots of small hulled death... dual and triple weapons on the ships, no defense. Not needed. Small ships fleeted have no trouble wiping out medium hulls, and you can pack more of them into the same level of fleeting. And that's a tech even. AI doesn't adapt to your designs. It only adapts to its research.

I do like how small ships can roll off those Mars type worlds pretty quickly, leaving your home world to kick out a fast constructor every turn. That fast constructor is then useful for galactic domination. Game won.

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Star Pilot, I've definitely seen the AI adapt, though not as consistently as I'd like to see. I don't know if it's because the AI usually goes to war and slashes its research budget (whereas I raise it after I get my initial defensive ships ready) so it can't compensate, or if it's trying to compensate against multiple opponents and is waffling so much it gets battered by all of them. Wow, this new dimension is going to give the AI dev(s) a massive throbbing headache. Multi-front wars just took on a whole new depth, since you can't always use the same ships on the same fronts, so it will have to know when to make what ship types where

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What I've seen is that it is the techs researched/traded that are incorporated into the AI's ships. Not designs to beat a particular opponent. For instance, I've had several games where I went all missiles, and was in the middle of all the other civs. Not 1 of the warmongers ever bothered developing Point Defense. Can you say their ships were toast? and that's with them coming after me because I let my military rating lag so far behind them (knowing I could crank out swarms of local fighters before they could get close enough to be a bother).

But, under similar circumstances, if I traded to any of the aliens my PD technology for something else, then they'd occasionally start making designs with PD (but not make dedicated ships to break my designs).

It's just my gaming experience so far. But it seems that if you don't trade any military tech around, they will stick to their traditional preferences rather then go for all three defenses, and then you can more easily fight them.

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I know this is an old post, but it also illustrates two points. One is that is is almost univerally better to crank out large fleets of small ships of total offense, and two, the AI needs to be tweaked to better adapt to player ship styles -> ie researching aggressively on the super-cheap missile defense if an opponent has missiles.

I also would like to point out that a lot of the all-offense debate could be ameliorated by making defensive elements take up LESS space than offensive elements. THat way you can make an excellent counter to the all-offense navy, which in turn would have to counter by switching weapons styles, or just overcoming in huge numbers and being the attacker in engagements.

MG

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I think the AI does a relatively good job at adapting on the higher difficulties.

I'm not so sure I agree with you on the second point. Defensive components do take up progressively less space the more you research. Also utilizing starbases helps heaps too.

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Alstein

Join Date 07/2004

+55

The AI definitely does adapt. I saw the AI switch from shields to point defense, and from lasers to mass drivers in the last game I played. By that point I had enough worlds to just outslug the AI though- my big problem at the end of the game was scraping together enough money for my mega transports.

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I also would like to point out that a lot of the all-offense debate could be ameliorated by making defensive elements take up LESS space than offensive elements. THat way you can make an excellent counter to the all-offense navy, which in turn would have to counter by switching weapons styles, or just overcoming in huge numbers and being the attacker in engagements.

Defense does take less room than offense, once you get out of the beginning techs. it's nothing unusual for me to drop 4 points of attack and replace it with 6 or more points of defense.

Personally, I've always had more luck with ships with defense, but that's because I'm usually the tech leader before I get into combat. With a tech lead, a balanced ship will out perform an all-offense ship, as long as you're adapting to the enemy ship designs.

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