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Subject: Questions about Alien A.I. rss

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Hello all,

We recently got the game and played though the first mission. I've still got a few questions about alien A.I.

1. I understand that you measure distance by area and not hexes. What I'm not sure about is whether you measure areas 'as the crow flies', or how far it would take to walk there. For example, if 1 agent is 2 away as the crow flies, but it would take 4 moves to get there, and another is 3 away, which one would be considered closer?

2.The <3> rule on the Xeno-Beta says "Move 1 area toward the closest agent and attack with Blaster". What if there's an agent at <1> or <2> distance away who the Xeno-Beta can't see. Does he move towards the one he's attacking (the one at distance 3) or the closer one that he can't see?

3.The spine critter <+> activation says to move 2 areas toward the most wounded agent. Does that mean that if the most wounded agent is across the map, it will still run towards him, even though it may not be able to reach him, and there where other closer agents who it could have reached instead?
 
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Thibaud Dejardin
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padlock wrote:
Hello all,

We recently got the game and played though the first mission. I've still got a few questions about alien A.I.

1. I understand that you measure distance by area and not hexes. What I'm not sure about is whether you measure areas 'as the crow flies', or how far it would take to walk there. For example, if 1 agent is 2 away as the crow flies, but it would take 4 moves to get there, and another is 3 away, which one would be considered closer?

2.The <3> rule on the Xeno-Beta says "Move 1 area toward the closest agent and attack with Blaster". What if there's an agent at <1> or <2> distance away who the Xeno-Beta can't see. Does he move towards the one he's attacking (the one at distance 3) or the closer one that he can't see?

3.The spine critter <+> activation says to move 2 areas toward the most wounded agent. Does that mean that if the most wounded agent is across the map, it will still run towards him, even though it may not be able to reach him, and there where other closer agents who it could have reached instead?

1) You must distinguish two things.

First, the alien AI. It only considers the area. If one agent is at range 2 (at crow flies, because it usually doesn't matter, as a lot of aliens will be able to shoot because the agent is in LOS, or will automatically run melee to the agent), even if he is closer in number of hexes than an agent at 3, you must apply the "range 2" patern. Then the patern applies to that agent.

Second, when you apply the "+" rule, you sometimes must consider the closest agent. I always played it in hexes to move to the target.

2) The agent at "3" was effectively the closest agent in LOS when you decide who to attack. An alien won't change its target if he sees a new agent after moving.

3) Yes, in the case of "+", you don't care LOS, you only apply the rule. Effectively, the critter will go after that agent across the map. However, remember that the alien will redeploy next to an agent if possible, event if it's not its primary target.




Note that the AI is lacking some elements. For example, if two agents are at "range 2", the rulebook only tell you to take the most thretening move against he agents. I find it a bit subjective, so I apply a few houserules to "fix" this.
Betas are really weird when an agent is next to a door (he doesn't see any agent then move close to the door, then next turn he is melee, so he moves away, losing LOS, and so on...).

I use those general rules to help me "think alien".
Spoiler (click to reveal)
Additional: -Except when specified, default target rule is: closest / most health left / Alpha player / next player...
-Move from zone center to zone center but redeploy adjacent to agent(s) or door (except non melee aliens).
-Ignore other aliens, agents, doors and windows for alien movement purpose.
additional: -Always end move in LOS with targeted agent, or in LOS with any agent if the “+” rule apply.
Additional: -“Move away” priority: stay in LOS / away from targeted agent/ towards a teleporter or another alien.
Optional: -Only “IN LOS” non bleeding agents count for behaviour rule. Otherwise, apply the “+ “rule.
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Skaak
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Archange227 wrote:
If one agent is at range 2 (at crow flies, because it usually doesn't matter, as a lot of aliens will be able to shoot because the agent is in LOS, or will automatically run melee to the agent), even if he is closer in number of hexes than an agent at 3, you must apply the "range 2" patern. Then the patern applies to that agent.


To clarify, you always measure areas with a legal walking path (including when calculating the "closest agent" for {+} rules, so it's sometimes possible to have an agent that's closer as the crow flies not be targeted because the alien would have to go an area or two around to get to them due to the layout of doors or similar).

Archange227 wrote:
Second, when you apply the "+" rule, you sometimes must consider the closest agent. I always played it in hexes to move to the target.


Technically, this is also always measured in areas. If you have a tie, the alien targets the first agent who matches one of these criteria (going downward in importance):

1. The most wounded agent
2. The agent with the least health remaining

This is detailed on page 37 of the rulebook in section 8.10.

Archange227 wrote:
Additional: -Except when specified, default target rule is: closest / most health left / Alpha player / next player...


As I mentioned, this is actually already covered by the rules. You do closest, followed by most wounds, followed by least health, followed by "whatever's worst for the agents". It's rare to need to decide that, though, because it's unusual to have two agents with identical HP on the field who do not have differing numbers of wounds.

Archange227 wrote:
-Move from zone center to zone center but redeploy adjacent to agent(s) or door (except non melee aliens).


Technically, non-melee aliens should always redeploy adjacent, as well. This is generally the right move for the aliens (even if it means the alien doesn't get to attack next turn) because:

- It drastically reduces the things the agent can do on their turn (since evading is so expensive, they're probably not going to get to move)
- If the player has Close Fight enabled, then it's really nasty because it means the agent cannot target anyone other than that alien

Of course, you're welcome to house rule it otherwise.
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Thanks for the responses! I'm still a little confused about my second question.

Say The Xeno-Beta is 3 areas away from an agent he has line of sight to, but on the opposite side of him, 2 areas away, there is another agent he doesn't have line of sight to.

I understand that his <3> rule will activate and he will shoot the agent 3 areas away. What I don't get is which way he'll move. Will he go to the one he shot at or the closer one 2 areas away?
 
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Skaak
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padlock wrote:
I understand that his <3> rule will activate and he will shoot the agent 3 areas away. What I don't get is which way he'll move. Will he go to the one he shot at or the closer one 2 areas away?


The Xeno-beta moves toward the agent it shot at; aliens always maintain the same target unless the AI rule tells you differently (which I don't think any in the base game do).

Thematically, the Xeno-beta is totally focused on the agent it can see as the clear and present threat. It would only listen to its intuition about agents that it cannot see if there is nothing else to distract it.
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Skaak wrote:
padlock wrote:
I understand that his <3> rule will activate and he will shoot the agent 3 areas away. What I don't get is which way he'll move. Will he go to the one he shot at or the closer one 2 areas away?


The Xeno-beta moves toward the agent it shot at; aliens always maintain the same target unless the AI rule tells you differently (which I don't think any in the base game do).

Thematically, the Xeno-beta is totally focused on the agent it can see as the clear and present threat. It would only listen to its intuition about agents that it cannot see if there is nothing else to distract it.


Thank you Skaak, I think I get it now.

I guess what confused we was the wording of the rule, specifically the "...towards the closest agent" part. At that point, you've already selected a target, and you know that he's 3 areas away. If there are multiple valid targets, then they are all at 3 areas away, so they're all technically 'the closest' agent. It seems like a completely unnecessary clause.
 
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Thibaud Dejardin
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Skaak wrote:
Technically, non-melee aliens should always redeploy adjacent, as well. This is generally the right move for the aliens (even if it means the alien doesn't get to attack next turn) because:

- It drastically reduces the things the agent can do on their turn (since evading is so expensive, they're probably not going to get to move)
- If the player has Close Fight enabled, then it's really nasty because it means the agent cannot target anyone other than that alien

Of course, you're welcome to house rule it otherwise.

It's usually true except for the xeno-betas and xenogreys.
It doesn't make sense for a xenogrey flying away from an agent to purposely go melee to another agent.

For xenobetas, even with the "blocked in melee" thing, except if you do use Close Fight enabled, that's not a big deal because you're usually always stuck in melee, in the core game. And the beta usually have more than one activation during a round. So he acutaly often lose an opportunity to attack and doesn't even block the agent, because he moved before that.

But it's effectively what the rules are, you know them so good it's really impressive!
The part in the "spoiler" is effectively my houserules. I feel it more intuitive/easier to remember from a game to another.
I always hated the "most agent" thing. I only apply it when specifically mentionned (like in the "+" behaviour).
 
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Skaak
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Archange227 wrote:
But it's effectively what the rules are, you know them so good it's really impressive!


You too can gain this level of knowledge! All it takes is obsessively stalking Agent S on the BGG forums for ~1.5 years.
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Skaak wrote:
Technically, non-melee aliens should always redeploy adjacent, as well. This is generally the right move for the aliens (even if it means the alien doesn't get to attack next turn) because:

- It drastically reduces the things the agent can do on their turn (since evading is so expensive, they're probably not going to get to move)
- If the player has Close Fight enabled, then it's really nasty because it means the agent cannot target anyone other than that alien

Of course, you're welcome to house rule it otherwise. :)


I'm not sure what to think about this. I agree that the penalties are significant and it makes sense to cripple the agents in this manner. However, the rules read "the alien MAY" move adjacent. It doesn't say the alien *should* move adjacent. But, maybe I'm forgetting another part of the rule. Also, I just can't see it thematically. If you know you're running away, then wouldn't you try to keep that distance int he first place as much as possible. Unless the alien is sacrificing him for the good of everybody.

Just wondering what other people think about that.
 
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Stephan Beal
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wsmithjr wrote:
I'm not sure what to think about this. I agree that the penalties are significant and it makes sense to cripple the agents in this manner. However, the rules read "the alien MAY" move adjacent. It doesn't say the alien *should* move adjacent.


The rules say (somewhere) that if a judgement call is needed then the aliens "should" do whatever is most advantageous for them. IMO that generally means engaging the heroes to keep them from targeting ranged-attack aliens (or get them to spend precious actions to _attempt_ to disengage).
 
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sgbeal wrote:
The rules say (somewhere) that if a judgement call is needed then the aliens "should" do whatever is most advantageous for them. IMO that generally means engaging the heroes to keep them from targeting ranged-attack aliens (or get them to spend precious actions to _attempt_ to disengage).


Additionally, although it's not in the rules Agent S has explicitly stated that aliens always move to engage.
 
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Skaak wrote:
Additionally, although it's not in the rules Agent S has explicitly stated that aliens always move to engage.


Well, then that settles it then. Thanks.
 
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