NOTE: Verified and obtained the exact formula in the Constructibles.xml file in folders for each age.
NOTE2: x axis is the cumulative food requirement. Basically, how much food do you need since the founding of a settlement.
Couple of things we can learn from this-- (with Edits, after some more thought)
-The new growth formula provides faster growth starting a population of 6, 13, and 24 for the Antiquity, Exploration, Modern Age, respectively, compared to the old formula.
-Growth is slower beneath these thresholds, in low-population settlements. Basically, this is intended as a nerf to wide play (more cities, less towns) and a buff to tall play (less cities, more towns).
-The biggest boost is that the rate of growth in the Antiquity Age is now SO MUCH faster. Now it takes only ~3000 total food since the settlement was founded to reach true population 12, whereas it used to be ~7500.
-Growth gets a lot slower in the later ages, but only for small settlements. That population 12 city at the start of Exploration is now on a fast track again, compared to previous. It takes only ~32000 vs ~68000 for a population 12 city to grow to population 24.
-The modern age is slowest. Good luck growing your smaller settlements. Your tall cities over true population of 24 will grow faster than version 1.1.
Last edited: