A question have I.
Civ X and Civ Y have access to the same tech. Said tech enables Building x and Building y. I would like Civ X to be able to build Building x but not Building y, while having Civ Y able to build Building y but not Building x.
My question is: what are
all the possible ways of doing this (if any)?
Thanks in advance.
I don´t know, if I can tell you
all possible ways of doing this, because I don´t know everything. But I can tell you how I did it in CCM (Civ Complete Mod) and another much more complicated way how to achieve the same result.
In CCM I wanted that the two machinegunners, that are available with Civ Complete (the German and the US-one in the PTW Extras) are beeing autoproduced by buildings that are available with the tech "Totalitarism" as they have much better defense values as the normal infantry units.
I gave the Germans an Era-None-Tech called "German Flavour" which let them build a very cheap special building, the German flag.
Then I set the building, that should produce the US-machinegunner for 30 civs to be available with the tech "Totalitarism" and to go obsolete with the Era-None-Tech "German Flavour" that is only available to Germany.
Then I set the building, that should produce the German-machinegunner, to be available with the tech "Totalitarism" and with a German flag-building as perequisite. Now both buildings are visible on the techtree.
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A more complicate way with the same result would be, to give all the other civs also an flag with a special era none tech that is needed as a perequisite for the building that should be available for 30 civs.
A small advantage of that methode is, that now the standard-building for 30 civs can go obsolete with a technic in the future.