I'm very sorry for floding this subforum, but once you've started to mod, you can't stop. I intentionally do not put all my questions in one thread as splitting them up as seperate threads should make it easier for other potential modders to find them.
QUESTION I: SUPPLY-STORE-CAP FOR STRUCTURES?
Somewhere it has been mentioned that also in RoP (newer games seem to have a more detailed and moddable supply-decay-mechanism?) there is a certain cap on supply-storage in structures. I'd be very interested in how large the storage is and if we can mod it (e.g. is it linked to city-level?).
QUESTION II: LOCAL SUPPLY
There seems to be a basic "local-supply" variable in Settings/General.opt, called "CountrySideSupply", which is 1 per default. So I guess that countrysides are supposed to produce supply.
Characteristics of local supply
As far as I know, this locally produced supply is supposed to be bound locally, i.e. it is not handled by the automatic supply-system. Moreover it does not accumulate from turn to turn.
Amount of local supply
How much local supply does a "countryside" offer? This guide
(see Simple Supply) might give us some hints. But I have no certainty at all that this even applies to RoP.
What I can say for sure is that there is a supply-value in the terrain-files*, specific to weather, which probably indicates how many supply points are available in a certain terrain/weather per turn. It remains unknown if civ-level and other factors (loyalty, looted) apply.
As for structures, the terrain-files for cities and forts are missing supply-entries. However, this is the case even for WiA, in which local supply is clearly active. It seems as if the amount of local supply that a structure contributes is set in the GameData/Structures-files: while the entry "SupplyProd" refers to the supply generated for the automatic supply system, the entry "Supply" refers to the local supply contributed by a structure.
Consumption of local supply
Now this is the biggest riddle of all. There is no chance at all to see if and how much local supply is available in a region (unlike WiA, where you get to see supply levels). Needless to say that this makes gathering information on how local supply works via testing impossible. So far my impression is this:
1) Every element first tries to satisfy its need for supply via the supply of the automatic supply system (taking it from supply wagons, supply assets/reserves, bateaux, structures). Perhaps these unit attributes overrule the priority of the automatic supply in favour of local supply: *Pillage* // always force a pillage roll; *fullpillage* // always force a pillage roll and always succeed?
2) If there is not enough supply available in the automatic system, the element tries to draw on local supply.
3) Whenever a unit needs to attempt to draw on local supply, it needs to undergo a forage-check (unless the regions' loyalty is greater than 75%?)
[INDENT]If positive: the unit draws on local supply; region remains unlooted[/INDENT]
[INDENT]If negative: the unit draws on local supply (or not?); region is looted (red marker appears, local (and global?) supply severely reduced until the region recovers (in spring)[/INDENT]
Note that you can easily increase the chance to live off the land without looting by giving all elements (expert-)forager abilities.
4) A unit that draws on local supply consumes the local supply that is available (the amount of which we can't see).
[INDENT]If there is enough local supply available to feed the whole force, then you will see in the game that your elements have not lost any cohesion or hits even though having been totally out of supply. Also, there is no message in the log. (A message like "X has successfully drawn on local supplies in X (x chits consumed), region not looted" would help a lot)[/INDENT]
[INDENT]If the local supply in a region is not sufficient, then you will get the message "X is completly/partially unsupplied in X, suffering X hits, etc.". It would be interesting to know how the available supply is distributed to the elements. [/INDENT]
All this is unfortunately completly hypothetical. I'd be very gratefull for any hints or clarifications. Luckily, I've found a way to mod around this complex of uncertainties, simply by planting a lvl 1 city in almost every province and at the same time reducing the automatic forwarding to a minimum. Basing the system on local supply that accumulates (lvl 1 cities everywhere, no forwarding) might even be a better representation of what I want to achieve. With supply that does not accumulate, you can't really refuse supply to your opponent (simply by consuming it).
*There is also a supply consumption variable SupUsagePerc in the terrain files to increase or decrease supply consumption of troops in a certain terrain/weather. I suppose that this is indeed appplied to the troops need, which will draw on the automatic supply system before it turns on local supply?
Explanation why supply is important to me
I'm going to give a rather long explanation as soon as my mod is ready to deserve its own thread. Basically speaking, since I want to focus on the micro-level of the AGEOD-engine (the vanilla games are rather concerned with macro-aspects), supply is an absolutely essential mechanic. I want to make armies depend on an equal mixture of central supply (wagons+depots, field bakeries) and local supply – both systems that offer light troops new possibilities and also open up room for tactics.
E.g. if armies depend on local supply, destroying or consuming supply in a region that the enemy is going to enter can be a very valid tactic to at least slow him down (for he then has to wait for the slow field bakery to catch up and/or for supply wagons going back and forth between army and depot). Historically, it was a quite common action to strip regions of their supply (which in this case primarily means green fodder; any army needed loads of it, not just cavalry, but also for the horses drawing the infantry baggage-wagons, generals' and officers' baggage wagons, supply wagons, pontoneers' wagons, wagons for the wounded, etc. etc. ). However, to make this tactic work, we also have to create the adequate setting: a turn-intervall of 7 days (instead of 15) and an internal supply-store of only 1 (instead of 2). Thus, not only will forces need to depend on supply every turn (having them act 30 days totally independently of supply was quite insane, to be honest), but also they will be unable to simply "jump over" regions that might be problematical in terms of supply, simply because of their "lower" movement allowance per turn. E.g. I can't damage my enemy by consuming all the supply in region A if the enemy force can simply move through this province in one turn, and if he only needs to check supply every two turns anyway. So, setting a lot of parameters right makes the potential depth of the engine shine! You can create so many exciting situations once it is neccessary (and secure enough) to split up the giant stacks a bit and manoevre around, once you start to anticipate how many days the opponents' force will need to get here and there, and once you actually order force-marches.
Another example would be hussars trying to intercept a supply wagon. With 15 days-turns, the supply wagon can easily "jump over" a province, without the opponent having any chance to react to it.
As for the AI: It doesn't seem to suffer cohesion and hits-effects of lack of supply anyway (only the combat mali?), so the new system doesn't put the AI at too much of a disadvantage. You can watch as an AI stack is totally cut off from any supply for several turns, the supply-overlay shows red points, but still the PWR of the stack does not decrease at all. However, since stacks tend to be out of supply rather often and therefore the AI carried out "resupply"-agendas all the time, I had to adjust aiCLR_SupplyPerc|50 (was on 90). Works fine.