Hi, I'm trying to create a set of techs that are civ-specific at the beginning of the game that allow access to specific bonus resources (wheat, rice, cattle, pigs, maize, etc.). I'd like them to be tradeable, so that these bonus resources gradually spread across the map, simulating the diffusion of cultivated plants and animals across the globe.
I've tried making these techs no-era and not required for era advancement, but the no-era flag makes it impossible to trade them. Any suggestions?
I had something I was thinking of a while back, might be of some use for you.
Have a resource on the map "fertile land" or something like that, then give the various nations or culture groups (whoever you want to eventually be able to produce a particular resource) a unique tech -- ensure the tech is set to no era and preset the techs in the beginning of the scenario for those factions.
Have that tech be required + some other tech or whatever makes sense for you to to be able to build some building, have the building thanks to the EXE mod build the resource you want. Have the resource you want be tradable, have all other factions that aren't the faction that has the the tech have a building that is made obsolete by that original tech, have them build something else. . . .
Example to better illustrate:
Resource "fertile ground" is scattered randomly through the map.
Rome has unique no era tech "ROMAN Wine"
ROMAN wine tech + access to fertile ground (either in the trade network or locally whatever you decide) allows you to build a vineyard.
EXE mod is customized such that the improvement "vineyard" produces the resource "wine".
Trade "wine" with other factions.
Other factions have an improvement "Winery" which requires the resource "wine"
EXE mod is customized such that the improvement "Winery" also produces the resource "wine".
The improvement "Winery" is obsolete by the tech "ROMAN Wine" thus, only non romans produce it.
Now "wine" initially exists only with Rome, but over time everyone would produce resource "wine" once someone trades it with them.
Make whatever modifications to this chain you want, but this would spread everything. Perhaps it might make sense to have "animal husbandry" or something like that have Mongols and some other steppe peoples have access to "grazing pastures" and then have them slowly share horses with people through stables or something similar.