AI Afraid of a Human Light Cruiser?

[Hans_Lemurson]

An AI fleet containing 3 Teros Heavy Cruisers (and one troop ship) headed for Deneb my only colony with a Space Station, that had just built a Human Light Cruiser. 1 on 1, a Human Light Cruiser can take on the Teros ships, but I did not have any deflectors (big problem!), and they outnumbered me 3:1. My fleet was off attacking one of their colonies, and would not arrive for many turns. I feared the worst when the Teros arrived, that they would blow my CL out of the sky, destroy my Space Station, and bomb my 2nd best manufacturing colony into the stone age.

Upon arrival, I got a notification of a "Teros Encounter at Deneb". I opted NOT to begin a battle I knew I could not win. With trepidation I hit "Next Turn".

...And nothing happened. No invasion, no bombardment, no destruction, NO ATTACK! In fact, the Teros were redeploying one of their Heavy Cruisers back to a home system, leaving just 2 to threaten me.

A quicksave test battle showed me that I was a fool to even consider attempting to drive them away. I just barely penetrated their shields before being torn to ribbons by their Ion Beams. Even with 2 Heavy Cruisers, I was still in mortal danger. With some minor worry, I hit "Next Turn" again.

...No attack. In fact, ANOTHER Heavy Cruiser departed, leaving only one left to face me. I'd still lose, but my fleet was going to arrive next turn. I fought a small battle, destroying a Scout Cruiser before retreating my ship, and hit "Next Turn".

All Teros Ships have now departed the Deneb system. (Interestingly, my damaged Light Cruiser retreated BACK to Deneb from Deneb. Is this intended for defender retreats?)

The entire Teros attack has amounted to NOTHING. They never initiated a battle when they had superiority, and instead withdrew their ships from the system. Were they afraid of my Light Cruiser, or was this the result of poor planning on the AI's part. It LOOKS as though this was supposed to be an invasion, but when they arrived, they saw they didn't have the forces to take my planet, and so just decided to go home. Does the AI ever mount successful invasions?

[zolobolo]

Upon arrival, I got a notification of a "Teros Encounter at Deneb". I opted NOT to begin a battle I knew I could not win. With trepidation I hit "Next Turn".

If they do not attack upon their arrival, they will not attack unless the balance of force tips further in their direction

Was you base a Star-base with defenses and did you have planetary defense? These might have tipped the odds in you favor and deterred the attack

A quicksave test battle showed me that I was a fool to even consider attempting to drive them away. I just barely penetrated their shields before being torn to ribbons by their Ion Beams. Even with 2 Heavy Cruisers, I was still in mortal danger. With some minor worry, I hit "Next Turn" again.

If you attack, you do not have the support of starbases and planetary defenses so you start off from a much worse situation

Didn't they invade after you have lost the attack?

my damaged Light Cruiser retreated BACK to Deneb from Deneb. Is this intended for defender retreats?

Yes, retreating ships will stay in the system as long as the faction has a colonised planet there. I do not necessary agree with this mechanic as the defender can chose to engage but I can understand that it gives escaping ships a chance to fight again in the same system for another planet with proper defenses

It LOOKS as though this was supposed to be an invasion, but when they arrived, they saw they didn't have the forces to take my planet, and so just decided to go home. Does the AI ever mount successful invasions?

While it may look like that it is not necessarily so. did you for example notice if the transport has reloaded its cargo to AI planet?
The Heavy Cruisers (or part of them) might have just been there to protect the AI planet

Yes, the AI can pull of proper invasions and while there are surely things it can be improved upon I do think that this logic works well.
What might cause interesting situation to the player are uncommon map settings and scenarios e.g.: Sparse star system, multi-front war of the AI etc...

[Hans_Lemurson]

There were no starbases or any sort of planetary defenses backing up my Cruiser. Just the defenseless Space Station needed to build it in the first place. Maybe the AI was treating that as if it were as strong as a Starbase?

I didn't check whether the AI would invade if I lost my Cruiser. They only had one transport, which wouldn't have been enough to capture the planet. All they could have done is bomb me a bunch. Does the AI avoid destroying infrastructure on worlds it wants to capture? But even so, it still should at least have tried to achieve space superiority.

I think it just thought my defense was too strong. Pretty weird.

[zolobolo]

There were no starbases or any sort of planetary defenses backing up my Cruiser. Just the defenseless Space Station needed to build it in the first place. Maybe the AI was treating that as if it were as strong as a Starbase?

I didn't check whether the AI would invade if I lost my Cruiser. They only had one transport, which wouldn't have been enough to capture the planet. All they could have done is bomb me a bunch. Does the AI avoid destroying infrastructure on worlds it wants to capture? But even so, it still should at least have tried to achieve space superiority.

I would upload the savegame and post the situation as it does sound like a strange situation. Never had the case where the AI did not utilize its space superiority myself

[Hans_Lemurson]

I have attached the save of the turn when there are still two Teros Cruisers in the Deneb system, the third one has already withdrawn. I am still no match for this force, but the Teros don't actually do anything. Even if I send my Light Cruiser away, they withdraw a second Cruiser that turn, and then the following turn do a total withdrawal.

It really seems like the AI has simply calculated that there's no winnable fight to be had. Or maybe it found some other pressing need for it's ships.

[zolobolo]

I have attached the save of the turn when there are still two Teros Cruisers in the Deneb system, the third one has already withdrawn. I am still no match for this force, but the Teros don't actually do anything. Even if I send my Light Cruiser away, they withdraw a second Cruiser that turn, and then the following turn do a total withdrawal.

It really seems like the AI has simply calculated that there's no winnable fight to be had. Or maybe it found some other pressing need for it's ships.

Hi there, experimented a bit around with the save and came to he below conclusion:
Whatever is preventing an attack and invasion in Deneb has nothing to do with the current state of the game

Even if I scrap all the ships, stations, remove all but one pop from Deneb colony, they still do not attack, which can only mean that the AI script has already "decided" not to attack and do something else instead. Thus this seems like a glitch in the script but not regarding their threat evaluation (since I literally remove all threat and they still don't engage) but more likely an issue in their higher level strategy concerning fleet movement

Honestly, I have never seen such an instance in my 350+ hours of game-play and the only difference I can see is the AI difficulty selected.
I suggest you start your next game on "normal". The AI strategy will not be worse, don't worry about that. In theory they should only get less bonus resources but it might address the issue.

[Chasm]

The computer player might have lost a planet giving it the range to get there. In that case ships will autoretreat (happens to the human player also).

[zolobolo]

There doesn't seem to be any range issue - the AI has a colony nearby

Also noticeable is that the AI fleet only gradually moves out of the system. If there were a bug wiith range, the whole fleet would have departed in a single turn

[Hans_Lemurson]

Yeah, I initially thought that maybe it was because I had just taken one of their star systems (Gacrux), but their new colony of Rasalhague in the south was closer to Deneb than Gacrux was. They were clearly in range.

It just seemed like the AI had already decided that it had to leave, and had nothing to do at that location.

It was interesting to note that when their attack was launched, the three Teros cruisers each departed from three separate systems, each on a different turn. Their arrival was coordinated perfectly, all arriving at once as a concentrated force I could not hope to defeat.

And then each cruiser left one at a time on separate turns. Interesting.

[username]

Makes sense to me. If I were in the AI's shoes, and I showed up with nothing but warships, yet insufficient transports to take the planet, I'd just decide to leave without attacking also. Sure, I could blow your ship to bits, but that would be destroying a perfectly good ship that could be MY ship. Have you seen how utterly garbage Ashdar ships are? I want that ship! Sure, I could bomb your planet, but that would simply be destroying something I later intend to have as MY planet.

So, yeah, I'm leaving.