How does TRADE work in the game?

**socal_infidel** · 03-22-2007, 19:08

(Don't know how to edit my own post)

Forgot to add that it's the port_to_port_mp_min float line in the descr_campaign_db.xml that controls the distance between ports.

**alpaca** · 03-22-2007, 20:25

@Foz: The slight increase comes from a change in trade_base_income or whatever the keyword is

@social_infidel: Interesting find, this could allow a bit of tweaking to either make sea trade more important or less important.

**socal_infidel** · 03-22-2007, 20:39

@Alpaca

Yeah, I'd been trying to figure out how to increase the distances for awhile. Part of an effort to increase the emphasis on trade income and decrease the amount of income you get from farms. It just struck me as unrealistic (or maybe just unsatisfying) at how short the sea trade routes were in this game.

Especially if you check out some of these maps:

**Foz** · 03-23-2007, 07:23

@Alpaca: Yeah I know that's why... I just wanted to point out that the wharf buildings at least aren't entirely useless

@SI: Nice find. I agree about trade routes seeming too short... and was wondering myself where this was controlled. How much does the value of the average trade route seem to go up when you allow them to be 4 times longer (400)? I would suspect quite a bit, because it seems like the length of the route affects its value. Not only that, but you now give each port far wider choices of where to export to, which means they can also select more compatible cities to trade with, more easily avoiding resource overlap and the lost revenue it brings.

On a side note, when I see info like this, I always end up trying to think up more useful applications than just getting something we've been wanting (always nice). What came to mind for this is that it might help the AI considerably to have all the extra income that longer trade routes are bound to be generating. AI right now is excessively good at using up every last florin at its disposal, it just seems to run short of cash too quickly to get everything done that it needs to - it eats with its eyes, not its stomach. So, the influx of money might actually help the AI function efficiently by allowing it to actually do all the stuff it wants to. Granted the player may then be rolling in obscene amounts of money, but it's probably best to err on that side of things so the AI can at least put up a good fight. Besides, the player will probably have more trouble figuring out good uses for all that cash.

If you've played much with the higher distance, SI, could you comment a bit on what it seems to have done to the AI factions, if anything? I'm interested now

**alpaca** · 03-23-2007, 14:30

The royal pain in the butt with the AI is that it will always build buildings in every city (because of the automation), and then won't have much money left for units, which it will invest in cheap ones that are of course relatively costly to maintain and which it can't disband.
So the AI will often go broke if you don't play on VH where it has a cheat of 10k per round (and even then it'll sometimes happen)

**socal_infidel** · 03-23-2007, 15:29

Just did some testing and it appears that the increased trade distances not only doesn't help sea trade income, but in fact, hurts it.

This was done using my custom mod (which substantially increases trade income and reduces farm and tax income).

Genoa - port_to_port_mp value set at default 100:

Trades with Toulouse

Toluouse - port_to_port_mp value set at default 100:

Trades with Genoa

Genoa - port_to_port_mp value set at 400:

Trades with Bologna:

Toulouse - port_to_port_mp value set at 400:

Trades with Rome

It looks like that with the increased distance modifier, trade routes are chosen based on the furthest port you can reach. Not on whether you can actually make more trading with that port. It's not like Genoa ditched Toulouse (or vice versa) for a more lucrative trading partner in this case, so it must just go for the furthest port within distance (just a guess).

**alpaca** · 03-23-2007, 18:14

Aaah great, suddenly the name makes sense!
It's probably a setting how far the port the settlement trades with must be away from it at the very least. So if you set this to 400, you'll get trade routes only with settlements that are at least 400 mp away.

Incidentally, it looks like distance is detrimental to trade income which is a bit strange (notice how it exports the same wares to Genoa and Rome, but Rome only generates a third of the revenue - or did you sign a trade agreement with Milan but not with the Papacy?).