I wonder how to make it so the the player wants to build various units at the same time. For example 20 infantry, 10 tanks, 8 tank-destroyers, 7 artillery, 5 selfpropelled-artillery, 20 trucks, 8 jeeps. All at the same time (as combined forces, not just "only tanks" or "primarily artillery", balanced forces shall be the most efficient).

Very important, I'm talking ONLY about army composition, like how many units of each type are produced (are in the player's army). There is no map, no ordering these units around, nothing. Just the player has an army and the AI has an army and when there is a war these numbers are compared (with various modifiers like generals, doctrine, etc) and casualities are computed and the result of the war is given (defeat, marginal defeat, stalemate, marginal victory, victory).

Important assumptions:

- the game is NOT about war, the war is just an addition (important one, but still an addition to the economy/diplomacy/politics which is the core)

- there is no map or ordering units, just 2 armies (dry numbers) are compared and a result is given

- preferably it's simple on the surface (especially interface) but deep inside (like an advanced player can dwell into details of what units build when whikle a new player could just try to maintain a basic ratio of certain units to other units)

- it should be realistic (yet simple), so it mirrors real world military (but again, without making it too complex, at least at the surface)

The simpliest solution I can think of is fixed ratio of units (hardcoded).

For example the army should consist of 40% infantry, 10% tanks, 15% artillery, 5% selfpropelled-artillery. All units that are "above" the ideal percentage get a negative bonus to power (like infantry above 40% could only be worth only 3/5 on their original power value). The power of all units is then summed up and make the power of the whole army.

Similar units can substitute for another similar unit (like if you have not enough selfpropelled artillery but more than needed artillery then the additional artillery can act as selfpropelled with a minor penalty).

But that's a very unappealing solution, the player would just calculate the ideal ration all the time and try to match it... Without any logic or reason behind it.

I would prefer something more fluid. Like if your enemy has a lot of infantry you want more artillery (BUT NOT LIKE RSP SYSTEM!) Or if you have a doctrine of mobility then you need more selfpropelled artillery and less artillery. Or you have a stat called army mobility and if you have at least 1 truck per artillery piece you have these mobile (worse than selfpropelled) then the mobility stat is compared with enemy and something happens (some bonus is given?)

People are lazy, thats why the natural reaction would be to just choose the most overpowered unit and then collect as many as possible.

To avoid this you need to give each type of units its own weakness to get some rock-paper-scissors like effect and avoid having unbalanced units that are too strong or units that are all the same.

Additionally you could maybe have more than one type of factory and if people would only use one of them, they loose the parallel output of the other types of factory.

Fixed proportions I think is useless, that only shows larger numbers, but its not a more complex or interesting game if you are forced to have 4 infantry and 1 tank than if you would be just having a single unit with same combined strength.

1 possible soloution would be to start out each side with the same number of training/factory facilities (1 each for each type of unit to be aquired), located in the capital state.

Each unit would have a value and build time. The player and AI could designate a percentage of it's economy to produce military forces. Say like 15% then portion those resources to each factory / Training facility which then continuely produces what they produce.

The Bigger, badder units cost more and take longer to produce. Like in the game of Risk, the player / AI could allocate those military resources to different areas under control.

This way if the player puts a higher value on soldiers vs tanks for urban warfare those units can be concentrated on behind the scenes to be at the constant ready.

I personnally don't like to have to keep queing up different factories when "1 order" a certain combat unit runs out to make another unit. It would be nice to build artillary, truck, tank units at the same time at the same facility. For example: I would like to build 1 each of the forementioned, each has a different build time and cost, but all come out of the same factory at the same time.

A factory could produce all ground hardware but I could say concentrate on only 1, 2, or 3 Not all of them to buils the armies I want. I think that would enhance game stradegy play.

I wonder how to make it so the the player wants to build various units at the same time. ... There is no map, no ordering these units around, nothing.

First I'de like to propose that there is no such thing as a variety of identical things. If there are "various" units, then how do they vary?

Since we are talking about video game army composition, it seems reasonable choose victory as the score system, and assume the player will do so as well. Then we can measure the victory value of a given unit composition by how it performs against other unit compositions.

We can represent a Strategy as a particular unit composition. For example Strategy1 {10 troop, 5 tank, 0 artillery, 0 helicopter} versus Strategy2 {5 troop, 2 tank, 0 artillery, 3 helicopter}. The question becomes what makes one strategy superior to another? How do we score the fight?

Fixed proportions I think is useless, that only shows larger numbers, but its not a more complex or interesting game if you are forced to have 4 infantry and 1 tank than if you would be just having a single unit with same combined strength.

Technically, from the point of view of the rest of the game there could be just one unit, like division, and the side with most power (number of divisions * military technology) would win wars.

But, as a player, I feel it is much more appealing if I build not abstract divisions but infantry, tanks, artillery, etc (with proper cute icons of these). Even if they are very similar and it makes no difference what I build and there is no decision involved (in the worst case scenario, it would be nice if this army composition was at least a bit meaningfull and involve some room for a choice).

We can represent a Strategy as a particular unit composition. For example Strategy1 {10 troop, 5 tank, 0 artillery, 0 helicopter} versus Strategy2 {5 troop, 2 tank, 0 artillery, 3 helicopter}. The question becomes what makes one strategy superior to another? How do we score the fight?

Not exactly (I think). The goal is to make it realistic, which means all kinds of units are needed at the same time (maybe in slight different proportions based on combat doctrine and other factors). A strategy where you have 0 artillery is not a strategy at all but a suicide, your military is missing a vital component and you shall pay for it dearly.

In the example you gave the second strategy would be obvously superior, since it misses only one component (artillery) while the first misses two (artillery and hellicopters). The combat mechanic should punish the first strategy.

The whole idea is the concept of "combined arms". The requirement of different types of units working together and that the diversity is essential to victory (no specialization to certain units, at least not to a total degree). That's what I want to convey in this mechanic.

And yes, I know it would be probably less thrilling that a traditional rock-scissors-paper mechanic (that's why I want to try it in a game where warfare is not the core activity, if it turns out it sux it won't be that devastating ). Still I would like to pursue it (as a player I find it very lacking that there are no games that have a realistic take on a military, so I would like to experiment with that one).

I personnally don't like to have to keep queing up different factories when "1 order" a certain combat unit runs out to make another unit. It would be nice to build artillary, truck, tank units at the same time at the same facility. For example: I would like to build 1 each of the forementioned, each has a different build time and cost, but all come out of the same factory at the same time.

Definitely, production of units can't be done traditional way. I'm not sure how it should be done yet, but surely not by queing separate single units.

After posting Yesterday, I began to think about unit production. Then I remembered a game from the 90's called Cyber Empires. In this game up to 6 players or 1 player & 5 AIs or 1 on 1 would wage war on a planet in a turn base system. I will not go into detail on game play. However, Factories were built in player controlled areas. These factories had different cost. Basically the were 1, 2 or 4 bay factories.

These factories could produce a different unit in each bay or each bay could produce all the same unit.

Maybe your production could be controlled in much the same way. Simply, (or not so simply) design each factory to accept player input on what to build when.

Production did depend upon monetary resources. If money was low the production was slowed down. However in this case, limiting a 4 bay factory to production in only 1 bay did speed up build time.

We can represent a Strategy as a particular unit composition. For example Strategy1 {10 troop, 5 tank, 0 artillery, 0 helicopter} versus Strategy2 {5 troop, 2 tank, 0 artillery, 3 helicopter}. The question becomes what makes one strategy superior to another? How do we score the fight?

In the example you gave the second strategy would be obvously superior, since it misses only one component (artillery) while the first misses two (artillery and hellicopters). The combat mechanic should punish the first strategy.

The whole idea is the concept of "combined arms". The requirement of different types of units working together and that the diversity is essential to victory (no specialization to certain units, at least not to a total degree). That's what I want to convey in this mechanic.

I think it is a question of scoring. You have to have an elaborate scoring algorithm but it shouldn't be too hard. A simple way of doing it would be to calculate combat contribution not by the number of units of a type but of the root (or log) of said number. That way an army with more types with low numbers achieves much higher scoring than an army with few units and high numbers. Also you can easily add in bonus multipliers for attacker/defender, terrain, doctrine etc on a per unit basis.

Other options are more work, like creating a small fighting simulator that lets unit types attack other unit types in a preference order that does not reflect the efficiency order. Like everyone attacks tanks first but tanks are resilient vs most guys. If no tanks are present (killed or you didn't bring any) dmg hits the more squishy backline. Bring too many tanks and you have no fire power, to few and you lose as well.

Here you can also make an target order, an efficiency table and additionally work in terrain bonus etc. Also this system is easier to visualize/describe ingame. So it seems to be more work but easier to get an intuition for than the above simple calculation.

Something like this?:

infantry gets 25% bonus as long as there is a corresponding amount of reconnaisance vehicles(so they won't be ambushed)
recon vehicles get 25% bonus for corresponding # of helicopters(to cover them)
helicopters get 25% bonus from tanks(because they can better attack anti-air-units)

tanks get 25% bonus from infantry (because it gives them easier control over the area.)

You would have to make it difficult for the player to produce equal numbers of the various units else the mechanic is useless.

I'd go with something like this:

Artillery fires first, then tank destroyers, then tanks, then trucks/jeeps, then infantry.

By default, the 'firing' units fire at the next in line (tanks will fire at the trucks if there's any left, all the way down to infantry, and back to artillery if that's all there is left).

Then, each type of unit deals a different amount of damage depending on what it tries to hit.

For example,

Tanks deal 10 dmg each vs trucks, but only 5 vs infantry (because they are scattered), yet they do 100 vs artillery, and their regular 10 vs tank destroyers and tanks.

This is a relatively simple system to implement. I'm not sure its simply to understand however, but it would keep things moving and always fresh.

If you expect the enemy to come in hard with tanks, you can just not bring trucks at all, and let them hit your infantry body (as it will be inefficient) and come in with your own tank-destroyers.

Of course, you could add aircrafts in there (possibly at the beginning) and may add the functionality that some units 'jump' others.

For example, you could say that if tanks reach the point where they need to attack aircrafts, they jump to the next in line instead because they can't fire AA.