Alien Intelligence: 0 is actually 1

[The Reaver of Darkness]

The Alien Intelligence attribute determines how many turns the aliens can "remember" the position of your soldiers. When a soldier is spotted by an alien, all aliens gain visibility of the soldier and will continue to track that soldier for the number of turns equal to their intelligence attribute. They continue to track soldiers who have moved outside of visibility range.

This attribute enables aliens to seek out your soldiers even when they must travel around corners to get to them. It is also the reason it seems like aliens can always see your whole squad when it comes to psionics: the psionic aliens have a high intelligence attribute, and if they successfully mind control one of your soldiers, they gain visibility of all of your other soldiers that the mind-controlled soldier can see.


I am trying to remove this psionic behavior in my mod. I want aliens to only be able to use psionic attacks on soldiers that have been spotted on the same turn. But when I set the psionic aliens' intelligence to zero, they maintain "memory" (tracking) of my soldiers through my turn and into their next turn. Shouldn't that one-turn tracking be what you get with an intelligence attribute of one?


I tested this several times in-game. An intelligence attribute of 0 means when the aliens spot my soldiers on my turn, they can use psi attacks on them on their next turn but not the turn after that. An intelligence attribute of 1 means when the aliens spot my soldiers on my turn, they can use psi attacks on their next two turns, but not after that.

It's more difficult to collect data from when the aliens spot my soldiers during their turn, but from playing quite a bit with their intelligence set to 0, I can confidently say that when the aliens spot my soldiers during their turn, they can use psi attacks on those soldiers during their next turn even when they have not seen my soldiers during my turn between the two.


Another way this could be fixed is to allow a value of -1. That way I can effectively set the attribute to 0.

[ohartenstein23]

Intelligence only matters for direct fire weapons and actively hunting down that soldier, psi attacks and blaster bombs only require that soldier to be seen and still in the 'memory' of an alien, not necessarily the one with psionic ability. You would need to limit the alien psi 'weapon' to LoS only if you want this behavior.

[The Reaver of Darkness]

Intelligence only matters for direct fire weapons and actively hunting down that soldier, psi attacks and blaster bombs only require that soldier to be seen and still in the 'memory' of an alien, not necessarily the one with psionic ability. You would need to limit the alien psi 'weapon' to LoS only if you want this behavior.

My tests say otherwise. While I can't be completely certain (because the aliens sometimes choose not to use psi attacks when they can), I have ran several tests by getting some soldiers seen and then moving them to a place where they can't be seen. The intelligence attribute of the psi users is what determines how many turns they can track the soldier. I used Sectoids to check this. The site contains at least one engineer which has an intelligence of 6, and all of the soldiers have an intelligence of 3. The single leader has an intelligence of 0. I saved the game after getting several soldiers seen and running them back into the transport. The leader will almost consistently use a psi attack on the next turn, but only once any turn after--which might have been due to a vision/occlusion bug. I tried about ten times just in this test alone. The intelligence attribute of the psi-users has a clear effect on how long they can track my soldiers.

Furthermore, using line-of-sight psionics will not give the results I desire. I want units to be able to use psionic attacks on other units they can't see. I simply want to enforce that the aliens must see your unit on the same turn as they use the psi attack, exactly in the way X-Com is limited.


In summary, what is happening:
Intelligence 0 = 1 turn "memory"
Intelligence 1 = 2 turn "memory"
Intelligence 2 = 3 turn "memory"

What should be happening:
Intelligence 0 = 0 turn "memory"
Intelligence 1 = 1 turn "memory"
Intelligence 2 = 2 turn "memory"