Walkin's Supply Model


Dec 8, 2008
In order to keep this reasonably simple, I make the a few general assumptions and gloss over related but not-specific items.
  • I have thought about it a lot, so will post more later on topics such as corruption, morale, skills etc etc.
  • The main one is assume a national-level resource pool.
  • It is also assumed in this that every time you try and get supplies out of the resource, they are there.
  • The values are only guesstimates and would need to be tested.
  • There would be a game toggle which turns off the need for supply

There are a series of items/products which are supply goods. Supply goods need to be provided to a unit periodically (their upkeep cost). These items are:
  • food
  • water
  • fuel (each type has its own item-petrol,gas etc)
  • general supplies
  • medical supplies
  • ammunition
(Gold is also an upkeep cost, deducted on a turn basis but not dependent on supply routes).

Supply Usage
Supplies are checked to see if they can be 'topped up' each turn. This means while in a supply radius your supplies would be constantly 100% (used and then refilled in the same turn). The supply usage rate is different depending on the type of supply:
  • Food and water - used at a rate of 50% per turn. (The unit will take 2 turns without supply before running out of food).
  • General supplies - some used every turn.
  • Fuel could be (approx.) 25% usage per turn, so it can go for 4 turns before it runs out. A unit without fuel can no longer move; planes will not be able to fly missions.
  • Ammunition is mainly expended during battles and some actions (e.g. “lay dense minefield”). (At this stage I am thinking ammunition supply is only for artillery-level technology, not individual troops).
  • Medical supplies are only expended to heal the injured, or to perform humanitarian actions (in settlements).

How does Supply work? - The Supply Zone
  • Any unit in own or allied territory automatically supplied.
  • Any unit in territory with open borders automatically supplied.
  • Any unit in friendly/neutral territory with supply agreement supplied (the supply costs come FROM the other territory, with additional hefty gold cost)
  • Any unit with 50 or less people is automatically supplied with food, water and general supplies. (This effectively means that early stone age units and scouts will be free of supply limitations).

Not all units will have all supply needs. e.g. nuclear subs will need ammunition (though not for a long while), but not need anything else.

If its not one of the above then the unit must be within a supply zoneto be re-supplied. At first this will be only 2 tiles from a friendly border (as above) or a road connected to a friendly city (as above). So in basic terms an incursion into enemy territory will require an intact road/rail network (which was the main benefit for roads anyway). A visual toggle would show supply zone.

Alternatively, a "supply wagon" unit (radius 2 tiles) can be moved into position and provide a normal road-like, but movable supply radius. If the supply wagon is attacked, then it is destroyed and the supplies are taken by the attacker. Supply can also moved down a river (supply barges, radius 3 tiles) or across an ocean (supply ships/subs, radius 5 tiles).

You can also build a tile improvement of a supply base (fortification + storage). A supply base will automatically use its stores to supply units in the event of the supply network breaking. This will only supply units to the extent of the supply bases’ stores (not indefinitely). It will need to be defended because it represents a nice little booty for the enemy.

Supply drops can be made by aircraft to re-supply units not connected to a supply network. A supply drop supplies all needed supplies for the units on the tile (regardless of quantity of need). Supply drops can also be made to cities under seige.

Resources are taken from the land wherever possible. Units with a freshwater river or lake on the tile, can refill their water needs from that. Food is extracted from the tile (which causes desolation if it’s a large army). A conquered city is plundered for any needed resources.

Technological advances will extend supply radius, and reduce supply quantities required.

Supply Issues
Corruption is also a factor in the required supply goods, if you have a high corruption then your units will have higher supply costs (as the middle-men take "cuts").

Some actions may be restricted due to lack of supply. E.g. “lay dense minefield” will not happen if the unit has no ammunition. Units without ammunition will attempt to retreat from a battle; or if ordered to stay and fight, most will AWOL. Units without food/water and down to 0% supply will break a siege automatically. Units without food

Supply Distribution
  • if civic RATIONING is turned on, food will go to units before cities. (Except for cities who revolt, they will consume ALL of their own food, regardless of population/production sizes).
  • if MILITARY-ENTERTAINMENT is turned on, then -5 entertainers will also be considered a supply item.
  • It is possible that some individuals within a unit will be provided food and some will not. Units without food/water will be allocated as 'injured'

(If there is a mercenary component, then they would need to be paid upkeep on a per-turn basis. If cut off from the supply of any required upkeep [including gold], they abandon immediately).

When you start the game you choose which terrain type you want to start in. When travelling through your natural terrain you incur -30% general supply requirements; representing your natural affinity with the area.

Should food/general supplies/petrol be dependent on the type of terrain a unit is going through? I am leaning towards no. This makes it more realistic/challenging to conquer harsh terrain; but it also makes planning/strategy hard because usage is not at a constant rate. i.e. should travelling through desert require more water?

What do you think? Please provide any/all comments.


Dec 8, 2008
What - no comments? Is it too hard to understand, good, bad or otherwise?


Nov 20, 2008
Neat idea. You'd have to have a train of protected workers coming up from behind, laying down roads or railroads to supply your army. Or, as you say, protected supply wagons. And instead of supply barges, which would require rivers to be in the tiles instead of adjacent to them, why not just count tiles on each side of the river as being supplied as well as long as you can access the river from friendly territory? (Access, meaning, you have freshwater, river-adjacent tile(s) in your territory, connected to that same river). But neither rivers, nor roads, should work if they are disrupted by enemy zones of control. That's another addition that this scheme needs. Not hard-and-fast zones of control where you can't move your units, like in previous versions of civ. Instead, "soft" zones of control that disrupt these supply lines.

I would also simplify the scheme to:
Food + water = food.
Medical supplies + other supplies = gold

So, the more you go across terrain that doesn't have good food productivity or access to fresh water, the more food that must be deducted (this also assumes an empire-wide general food pool, which I also favor, with city growth being contingent on overall surplus food, plus the relative amount of excess health and happiness in each respective city to attract new settlers and encourage more births from existing citizens in that city, as opposed to the others).

And the more healing and fighting you have to do, the more gold gets deducted for your supply costs.


Mar 7, 2009
I see your point Zeiter about rationalising supplies to gold, and I'm almost convinced to agree with you.

Doesn't more available items though add more potential trade options? e.g. one civ could major on producing medical supplies.


Dec 27, 2008
Will I agree with the general idea of having supply as a part of the game, I err on the side of playability, with this perhaps being too complex for what, I think, shouldn't be a highly complex aspect of the game. I think there should just be supply wagons, and a supply line, or a clear path between your territory and your army. Anything more, I think, would mean that turns during war, which already can take a long time, may take even longer.

Having said that, it's a nicely thought through idea, Walkin.


Jul 24, 2007
I too would definitely like to see some sort of supply system, but as others have said, I feel the exact system you propose err on the side of being a bit too complicated. That being said, there is lots of good stuff there. I think if you limit to supplies to food and, for some units, fuel (either oil or coal), it would be manageable. If they can get this, they are also assumed to have access to ammunition and medical supplies. Well, it is strange that you get bllets when scouring the countryside for food, but we have to allow for a certain amount of simplification :rolleyes:. Need of water can be reprsented by much higher attrition rats if left without supply in deserts or other inhospitable regions.

I abhor the idea of having "supply wagons" you have to build and move around to supply your troops. There is enough to do during wartime already, and logistics are not fun (trust me. I was responsible for my company's logistics when I was in the army, and although being educational it was never fun.) Supply lines should automaticaly stretch from your empire to your armies, maybe with a distance limitation that depends on the technology and infrastructure (so you don't have to completely surround an enemy to cut his supplies, you can also do it by forcing it on a long enough detour). I agree with Zeiter on the zones of control.
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