How does AI reinforcement work?

[mindloss]

I have read http://www.arcengames.com/mediawiki/index.php?title=AI_War_-_AI_Reinforcements and other bits here and there, but I still don't grok it. To make things simpler, I'll break my confusion down into easier questions:

1) Does the AI receive a certain number of reinforcement points per cycle which it then converts to ships somewhere?

2) If so, is there any way to lower that number (other than lowering AIP, which I assume affects it)?

3) Specifically, does killing regular non-wormhole guardposts in a system lower overall galactic ship reinforcement? Does it even lower reinforcement for that system?

4) Does taking out a command center and everything else in a system lower it?

[x4000]

1. Yes, exactly.

2. No, you can never lower that number.  AIP is completely unrelated to this number (positive or negative).  The number of reinforcement points are based on the number of planets the AI does not control, and it caps out around 12 or 15, something like that (per AI player, as with everything reinforcement or wave related).  A bit different based on various sizes of maps.  The AI is granted these number of reinforcement points every x amount of time, where x varies close to linearly by difficulty level (so the harder the difficulty, the more frequently the AI gets a pool of reinforcement points to spend, same as it gets waves more frequently).  Unlike waves, there's not a random time component in the reinforcement point distribution, to my recollection.  Or at least not as much of one.

Reinforcements are two-factor, which I think is the source of most of your confusion: there are overall reinforcement points, which are at the galactic level.  You can't alter these in any way, aside from giving the AI more as you destroy its command stations.  But that's literally your only interaction with it.  However, all those points say is "do a reinforcement event at a planet," and the AI can choose which planets.  It can also choose to spend two points on one planet during one reinforcement cycle, or in rare cases (mostly home planets) up three points on one planet.  All of this is just the first of the two factors.

3. This is where the second factor starts coming in: what does a reinforcement event at a planet "translate" into in terms of ships?  Remember, there are between 0-3 reinforcement events per planet in the cycle, depending on where the AI decides to allocate its points.  Anyway, how a reinforcement event happens on a specific planet is enormously complex and is affected by AIP, number of guard posts at the planet, if there is a command station at the planet, and so on.  So: if you kill any guard posts at a planet, wormhole or otherwise, you substantially reduce the effectiveness of reinforcement events at that planet only.  There is no way for you to adjust this directly on a galactic level, with guard posts or otherwise.

However, indirectly, you can affect the galactic reinforcements by removing all the guard posts at valuable planets, and then keeping those planets below their planetary ship caps.  The AI determines which planets to reinforce at while being blind to how many guard posts it actually has at that planet.  It knows only if it can reinforce there at all (based on having any reinforce warp gate ability units, and based on having available ship cap), and if it makes sense to the galactic strategy to do so.

That might sound complex, but the strategy in question is simple: if there's a high alert planet that is near your planets and the AI spends a reinforcement point there out of its limited pool, you can control how many ships it gets based on how many guard posts it has there.  If there are a dozen guard posts, then the AI just got a ton of ships.  If there's next to none, then it got a fraction of that.  If it's just the command station and the wormhole guard posts, then it got close to comparably nothing, and in return it lost a reinforcement point that it could have spent elsewhere.  The key thing here is that if you'd killed the command station and the last guard posts, or if you let the AI planet sit there at ship cap for that planet, then the AI will not be able to reinforce there and so will have no choice but to spend its reinforcement points elsewhere, which actually is probably to the benefit of the AI since that means it gets more overall ships somewhere.

Another strategy that people use is alerting a bunch of planets in a part of the galaxy they never have any intention of going to.  That causes the AI to burn tons of reinforcement points in a useless area trying to defend against something you're never planning on actually following through on in the first place.  That's much easier and more effective as a way to alter the tides of galactic reinforcements.

4. So, per the above, no this has no effect on galactic reinforcements -- except to improve it.  By firstly giving the AI another reinforcement point if it's not already at cap on its reinforcement points, and secondly by making the AI spend its existing reinforcement points somewhere else.

It's kind of like water pressure in a hose: if there are 90 planets that the AI can reinforce into, then you have a loooooong time before you start seeing substantial buildup except on the planets you have on alert.  If you've alerted 90 planets, then each of those are also going to be filling up super slowly.  But if you've alerted 1 planet only, that one is always going to be an incredibly beast to deal with because both AIs will be sinking 2 points into it every cycle unless it's full already.  And if the AI is down to only two or three planets left in general, then it's going to be spending 2 points per AI on each non-home planet, and 3 on the home planets (and whatever points exist beyond those per-planet caps just get wasted, which is another way you can technically influence galactic reinforcements, but since it requires taking almost all the planets it has no bearing except in really small maps or really insanely long games).

Anyway, there's a variety of things you can do here, as hopefully I've illustrated above, but it's more indirect rather than being more exact.

[mindloss]

Thanks for the detailed reply. I think that cleared up pretty much everything.

However, the bit about the AI being blind to the number of guard posts at a planet is news to me. And you say a planet with fewer posts will get fewer reinforcements, if the AI does choose to spend one or more points there... so doesn't that mean that if you were able to tear through the galaxy and torch all guard posts on most of the AIs planets (actually just the on-alert ones, since aren't those nearly always preferred?), but leave the com center/warp gate standing (actually, do you even need to leave the warp gate?), the AI would likely spend most of its reinforcement points out there on its barren worlds and would generate very few ships overall? Or have I misread?

That was a mess of a paragraph, but hopefully you get my question. Torching guard posts == fewer ships (in general) is what I'm hearing.

[x4000]

However, the bit about the AI being blind to the number of guard posts at a planet is news to me.

Yep, I'm not sure I've talked about that with clarity in the past.  One thing to remember: each AI is not a single human-like opponent, but rather is a collective of sorts.  Different levels of the AI are allowed to know different things, and the galactic and planetary levels often aren't allowed to cross-share information.  Partly because that helps to lead to more interesting emergence, but also partly because it's how the AI is balanced in terms of "scouting" compared to what human players have to do.  Among other reasons.

And you say a planet with fewer posts will get fewer reinforcements, if the AI does choose to spend one or more points there... so doesn't that mean that if you were able to tear through the galaxy and torch all guard posts on most of the AIs planets (actually just the on-alert ones, since aren't those nearly always preferred?), but leave the com center/warp gate standing (actually, do you even need to leave the warp gate?), the AI would likely spend most of its reinforcement points out there on its barren worlds and would generate very few ships overall?

That would only work for a while, unless you kept a continual presence out there.  Removing guard posts from a planet does two things: 1) it reduces the number of ships the AI gets during each reinforcement; 2) it reduces the overall ship cap that the AI has on that planet.  So once the ship cap is hit on any planet, more reinforcements don't go there anymore unless the planet again drops below ship cap.  So if you make the ship cap very low on all the planets, then after a while they will all fill up and then you've got the mega-reinforcements stacked on wherever you're lowering the ship cap again (aka, where you're actually interested in going).  I wouldn't consider it a hugely valuable strategy to go on a massive guard post spree, because time would be working constantly against you.  Doing something that puts a large number of low-value planets on alert is much better.

Torching guard posts == fewer ships (in general) is what I'm hearing.

Eh... sort of.  On a per-planet basis, absolutely.  On a galactic level, there's really no stopping the tide of AI ships unless you take all their planets.  You can slow it down, but the time it takes you to do that slowing generally means that any benefit of the slowing itself is lost.  It's better to misdirect the AI, rather than trying to kneecap it; you're the little guy, remember, in this game's scenario.

Another thing of relevance: cross planet attacks.  If you're worried about the AI's galactic ship count because of CPAs... don't be.  If the AI has a hundred thousand ships on planets you are not on, what do you care?  They won't come after you except as part of CPAs.  And a CPA is going to have the number of ships it has regardless -- if there are not enough ships of the appropriate level in the galaxy, then it will take higher level ships, which is actually worse for you.  So there's actually very strong downsides to trying to kneecap all the planets, aside from the waste of time it is.

Neutering nearby planets that are constantly threatening you, or that you need to pass through, is great.  Putting a small force there that keeps them continuously below ship cap is even better.  Alerting distant useless planets of the AI so that it burns reinforcement points over there is also great.  Massive grinds through the galaxy to try to drag down the AI's global ship cap numbers are like trying to empty a lake with a bucket.  You could possibly do it, if you were persistent enough, but it's going to take way longer than you estimate and it's not really the most effective way to drain that lake.  Go for the plug, instead.

[Philo]

So if the AIP doesn't actually directly influence the number of reinforcements what does it do then aside from giving them new tech when you reach the treshold mark?

[TechSY730]

Wait, isn't it possible for the AI to sometimes take some ships from "over-reinforced" planets and free them? Admittedly, that would be a late game phenomenon, as the ship caps per planet would dictate the AI will try to spread out reinforcements first.

[mindloss]

On a loosely related note, so I don't have to start a new thread: it seems like SC Scouts trigger alert on the planet they're on. At least, every planet they visit "happens" to be on alert while I'm watching via my SC Scout. I don't remember seeing anything in the text about that effect... but I like it, if it's true.

Edit: Make that, triggers alert on its planet AND all adjacent planets (!)

[Hearteater]

So if the AIP doesn't actually directly influence the number of reinforcements what does it do then aside from giving them new tech when you reach the treshold mark?

It also unlocks new ships for the AI.  Which is not reversible if you get AIP reductions later by the way.  I can't recall what the points are for new ships, but around 200 AIP is the first unlock I think.

[x4000]

To the various questions:

1. AIP doesn't influence the number of the reinforcement events, but it does affect the number of ships that are in each reinforcement event.  Every time the AI goes up a tech level, the number of ships per event then also falls, FYI, before climbing again.  So it makes for a more linear difficulty increase rather than as much of a sudden jump.

2. Also: yes, on over-reinforced planets the AI can do the border aggression thing.  And there's also barracks and then carriers to contend with on over-large AI planets.  Also if the AI is past a certain number of ships in the galaxy (somewhere around 75k, I think), it starts swapping out two lower-level ships for one ship of the higher level.  I intentionally avoided talking about all those mechanics because it muddies the core issue and question.  But suffice it to say, all these do is reduce the ship cap of the planet in various ways in exchange for... something (a trickle of free ships, a barracks, a carrier, or a smaller number of higher-tier ships, respectively).  These things can then cause the AI ship count on a planet to fall back below its shipcap without any involvement from you, but it tends to only happen on alerted planets or in the VERY late game of a very long campaign.

3. Yes, all spirecraft/golems, like all starships, like all fleets of something like 50-300 ships or more (depending on unit cap scale) cause the planet they are on, plus the adjacent planets to them, to go on alert.  The AI notices anything approximating an army in its territory.

4. Yes, the AI also gets more ship types from AIP, in addition to getting larger waves, reinforcements, CPAs, and so on.  It's the number of waves/reinforcements/CPAs that doesn't go up as the AIP increases, but the size of each one does go up with AIP.  Waves/CPAs don't have their number or timing increased or decreased by anything the player can do, but reinforcements have their number per cycle (but not their timing per cycle) increased as the AI loses planets, as described above.

[Philo]

Ok, so they get more reinforcements but the same amount of reinforcement cycles and reinforcement points as the AIP goes up am I right?

[x4000]

Ok, so they get more ships per guard post/command station in each reinforcement event but the same amount of reinforcement cycles and reinforcement points as the AIP goes up am I right?

Clarified that, but yes.