Is there any logic to what buildings remain in a city you capture? I see what appear to be very diverse results from similar [size, age] cities--sometimes 5+ nice buildings, sometimes nothing.

PS: I know wonders and settled GPs remain.

all culture buildings are destroyed cept military acads and acads and there is i think a 33% chance other buildings will get destoyed.

The buildings' conquest probabilities are specified in CIV4BuildingInfos.xml, e.g. the granary has
<iConquestProb>66</iConquestProb>, that's why it survives quite often.

All captured buldings lose their culture, unless you have a UB that upgrades a non-culture building into a cultured one.

However, wonders can never be destroyed unless the city is razed. If you recapture a wonder that was producing culture, the culture production is still removed. Because of this, never ever let the AI capture one of your culture cities if going for a cultural victory

Oh yeah, I knew about the cultural zap too, thanks :)

The buildings' conquest probabilities

Thanks Dan, good to know there is a logic at work. I guess the explanation for the diversity then is that the AI wasn't building many buildings in some cities.

I think this has to be my main problem with Civ IV. It just doesn't stand to reason when you capture a city it is effectively knocked back to the stone age. Why would an invading force destroy all the the city's infrastructure when all they have done is kill the defenders? Sure there might be some collateral damage but no the extent that you see.

It makes perfect sence. When you invade a city and you have to fight street-to-street or house-to-house, it's hardly suprising that a lot of the infrastructure is destroyed. There wasn't much left of Stalingrad by the end of the war.

Aside from culture buildings, Barracks, Stables and Walls are destroyed. Though, strangely enough, Drydocks can survive.

Castles get knocked down too. Not sure about bunkers, never seen the AI build em.

It makes perfect sence. When you invade a city and you have to fight street-to-street or house-to-house, it's hardly suprising that a lot of the infrastructure is destroyed. There wasn't much left of Stalingrad by the end of the war.

That's a big 'if' in there. Since the mechanics of warfare in this game are incredibly abstract I don't know how you can deduce that street-to-street fighting occurs. For instance if defenders are getting things like wall bonuses then that would imply they are actually fighting on the wall and being killed there ( I really don't see how a wall helps if the invading army is already rampaging through your streets). Especially since seige weapons reduce the wall/culture defence bonus, and don't flatten buildings directly.
There is no mechanic like in Total War series to pay a fee (or spend hammers/gold in Civ IV terms) to repair buildings - they get destroyed outright which is fairly unrealistic. Not least because things like Wonders seem to always come out of these things unscathed even if they lose culture.

I like the idea of being able to pay to repair a building - I agree things like walls or harbors wouldn't necessarily be completely destroyed.

Then again, the invading army would have instructions to FUBAR everything that spoke of the defeated nation wouldn't they? Look at all the History Channel footage of Nazi Eagles crashing to rubble across conquered Germany in '45.......So I agree all cultural buildings should go.

Also a lot of infrastructure would take a while to start functioning again -banks, libraries, etc - so the elimination of the buildings is a PC Game manifestation of that, I guess.

Just think of it as razing, you get gold when you capture a city, and the more buildings raze = the more gold you get.

the more buildings raze = the more gold you get.

Oh, is that right? I had wondered also about the diversity in 'loot' between captures, but hadn't thought to compare it to buildings remaining. Interesting.

For much added complexity, you should get a promt, everutime you capture a city. The promt should have options to tick on/off about whether to save buildings, or let them be tottaly destroyed, for a fee in gold, according to the original cost in hammers. Alternatively let the "keep" option cost gold and the "raze" option yield a few gold. That way, you have options, but must still be able to afford it. If you want to keep the city, you'll have to pay. But it might be worth it.

Bunkers (and bomb shelters) can survive. The computer did build them all over the place in late games (once I started bombing and they had the tech).

Not sure why drydocks survive and barracks/walls/airports don't other than it was coded that way.

It helps if you have a Spy in the city you're attacking, or even better if you have enough EPs to see into your enemy's cities. That way you can see what buildings each city has before you capture it. Generally, I find the AI has built plenty of culture-producing buildings which will all be destroyed on capture.

Castles get knocked down too. Not sure about bunkers, never seen the AI build em.

Castles survive culture flipping though, and produce 1 culture. All other culture producing buildings are still destroyed in a revolt.

I just justify the situation as good old fashioned sacking of the city. The troops go in and they rape the women and break a bunch of glass, and these justify the sounds you here with screams and breaking, which I always hear twice for some reason.

Anyway, what can you do, eh?

Yep, when a city is taken by force, it generally takes a lot of damage. Though you should be able to bombard cities with a chance of destroying buildings (especially late game bombers/Arty). And it would make sense to have a chance to destroy buildings whenever you are attacking a city, that might get too annoying and make a passive defense even worse than it is now.
The loss of culture on conquest is necessary, though.

Remember Civ II where the city lost 1 pop for every unit that attacked it? Well maybe not every attack (not really sure about this), but fairly often. Really pisses me off early game.

All captured buldings lose their culture, unless you have a UB that upgrades a non-culture building into a cultured one.

However, wonders can never be destroyed unless the city is razed. If you recapture a wonder that was producing culture, the culture production is still removed. Because of this, never ever let the AI capture one of your culture cities if going for a cultural victory
While that last bit is good general advice, if you recapture the city, the wonders will resume producing culture for you. I observed this just last night when I took Athens with Navy SEALs in the Next War scenario, then evacuated it via boat the same turn in the face of a huge stack. Sure enough, His Excellency recaptured it, and when I investigated the city that next turn, the wonders were once again producing culture. I don't see any reason that particular aspect would be changed by that mod, so I presume it's a stock rule.