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Fortification and sentry bug concerning AI in civ 1 ?


Apr 23, 2005
There might be some kind of fortification bug in civilization 1, where the AI cannot attack fortified units.

I noticed such a case with a musketeer on a mountain. Only after unfortifieing and refortifieing could the AI attack it.

If true then this could explain why the AI sends and stacks so many units against each other like phalanx to phalanx and such.

Could be interesting to investigate with debuggers/disassemblers, I wonder why you guys would find...

Analyzing the save game further may also have uncovered a sentry bug of some kind, where the AI's ships are sentries, they have "move/go to" orders but they can't move because their units/ships are in sentry mode...

In case you want to see some evidence, check out this youtube video:

Near the end of the video I inspect the save game and discover this sentry fleet of egyptians, I seek out to destroy it...

I also notice one of it's transport to be in "sentry" mode, only after I discover it with a nuke from my carrier does it start moving again...
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The musketeer thing is most probably not a bug, but rather the AI just not wanting to risk attacking a unit with such a strong defence value. I'm pretty sure the AI calculates its odds of victory very much like a human player does, and that in a lot of situations it will simply avoid wasting its units by attacking well-entrenched defenders. Even an unfortified green musketeer on a mountaintop already has a defence of 9. Fortifying it raises that to 13+.

On the other hand, the AI does have problems with pathfinding for ships. Its ships will sometimes get stuck near the north pole, on what some have called "the international date line", the 2-3 tile wide column of ocean where the map wraps around. It's a Bermuda Triangle of sorts, which causes navigational problems for both AI ships and human-controlled units crossing it with a "Go To" command (the AI moves all of its units with "Go To"). Human-controlled bombers that have been given a "Go To" command or have been ordered to fly home (by pressing "h") can get lost if they cross the line and crash if it's their second turn in the air. Ships with "Go To" commands can get stuck in a loop there. Judging by the minimap view in your video, that's probably what happened to the Egyptian ships. Some info on the issue can be found in these old threads (there certainly are others):
It's still strange, it had plenty of units around it and never ever attack for many many many many many turns, until I unfortified it...

So one could consider this a bug as well: "unit to strong to attack" ?! ;)

Thanks for the international date line bug report ! =D (This is very realistic, the F22 raptor jet had a similiar issue with it's computer systems ! =D Basically a math issue.)
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