Spreadsheet: Ground combat simulator!

[deathpickle (OP)]

Very surprised no one made this yet! But its nice I get to be the first. Not the greatest at math, but I dare say im quite proud of myself. It feels like the first time I beat stickranger after all those years unable to win as a kid. For context, this is my third attempt, the previous was vast in scale, with only half-useful results. I even finished it quickly this time in only 2 days!

here it is! Aurora Ground combat simulator!

[Warer]

Holy hell a single point of difference in racial armor makes so much of a difference it's fricking insane. Thanks for this, I would have had no idea how effective my weapons would be if not for this.

[Ulzgoroth]

Holy hell a single point of difference in racial armor makes so much of a difference it's fricking insane. Thanks for this, I would have had no idea how effective my weapons would be if not for this.

When armor and hp are stronger than AP and damage respectively, kill chance scales with the 4th power of the tech factors. (Because penetration and wounding both scale as the square and combine multiplicatively.)

[deathpickle (OP)]

yup, and increasing your armor-level never directly makes a unit more cost efficient when you factor the reduced numbers you'll be able to make, no matter their penetration or your racial armor! It does however make them more space efficient for transport, which is actually a big deal.

Test a 5000 squad of 1 armor infantry vs 2500 squad of 2 armor infantry (same cost and level.) You'll see they both are exactly even!

[Ulzgoroth]

yup, and increasing your armor-level never directly makes a unit more cost efficient when you factor the reduced numbers you'll be able to make, no matter their penetration or your racial armor! It does however make them more space efficient for transport, which is actually a big deal.

Test a 5000 squad of 1 armor infantry vs 2500 squad of 2 armor infantry (same cost and level.) You'll see they both are exactly even!

The latter deal damage half as fast and take proportionately 1/2 as many losses. (1/4 as many losses on half as many units.) That's exactly even in a simple matchup, yes. But there are ways to make it not even.

The former have twice as many built-in GSP worth of supplies, so if you're skimping on resupply units they can do more before stalling (though that becomes negligible if you're bringing plenty of supplies). They're better at occupation work, of course. And they're just as (non) durable as the armored infantry against heavier weapons, which can be a big deal depending on enemy force composition.

That's a lot of cons of the heavy infantry. Let me see if I can find some pros! Other than transport density as you say.

The armored infantry takes twice as many rounds of incoming fire to wipe out. So back on supplies, they're placing more stress on the enemy GSP. They take half the proportionate losses in any given round, so they produce a better Cohesion Rating making them harder to Breakthrough against.

I think their longer endurance can provide better protection of high-value units, since it's not uncommon for such units to survive better and die late after the infantry has been cleared out around them, but this might be deceptive, I'd need to run the math. It's certainly sometimes true though - if the enemy isn't using Front Line Attack, their units can't hit your units behind the front line, so the armored infantry does a significantly better job of protecting a support-line stack of Light Bombardment in a trench stalemate situation.

[nuclearslurpee]

The former have twice as many built-in GSP worth of supplies, so if you're skimping on resupply units they can do more before stalling (though that becomes negligible if you're bringing plenty of supplies).

This isn't true. The former formation has twice as much GSP but they use it twice as fast. In fact, the latter formation has the (small) advantage here since they require half as many supplies, thus only half as much BP dedicated to resupply units.

And they're just as (non) durable as the armored infantry against heavier weapons, which can be a big deal depending on enemy force composition.

This is actually one of the key disadvantages of armored units. If we have, for example, PWI infantry against unarmored infantry, then the extra +0.25 penetration of the PWI is wasted (along with the +1 and +0.25 GSP ton per soldier that PWI requires). Against an armored infantry or any other armored unit, the penetration of PWI becomes useful. Turning this around, armor-piercing weapons are proportionally more effective against armored units than against unarmored units.

This sounds obvious, so let me illustrate by an example: Let us compare unarmored (base 1/1 HP/armor) and armored (base 1/2) infantry units, each armed with simple PW (5 tons) for the purpose of analysis. The unarmored infantry costs 0.1 BP per unit, the armored infantry costs 0.2 BP/unit. We consider two cases, assuming equal tech levels all around:

• The attacker is armed with PW. In this case, the attacker has a 100% chance per hit to kill unarmored infantry (loss rate 0.1 BP/hit) and a 25% chance per hit to kill armored infantry (loss rate 0.05 BP/hit). Note that while it may seem like the armored infantry enjoys a 2-to-1 advantage, you can deploy only half as many armored infantry per BP and so the double number of unarmored infantry puts out 2x as many shots, therefore the loss ratio works out as even if you work through the math involved.
• The attacker is armed with PWI. In this case, the attacker still has a 100% chance per hit to kill unarmored infantry, but now has a 39% chance per hit to kill the armored infantry (loss rate 0.078 NP/hit). Even though the armored infantry can resist the weapon better than the unarmored infantry, it is not possible to "overkill" the unarmored infantry, so they perform relatively better against the armor-piercing weapon.

Of course there is the "extreme" case of, say, LAV, which as you already pointed out kills both types at 100% efficiency and renders the armored infantry a waste of BP. My point here is that even against semi-piercing weapons, armored units perform less effectively per build point than unarmored units.

The chief advantage of armored units is when you are limited by transport capacity rather than build costs, which usually means in the case of a major invasion (i.e., an alien home world) but also applies for, e.g., boarding combat or for low-tail operations like capturing spoiler race colonies. Unarmored infantry are the most cost-effective unit type, but of course easily the most transport-ineffective.

It is also worth noting that against most NPR armies, which are heavily biased towards PW infantry and CAP, the disadvantage of armor is minimal enough that other factors like evasion and breakthrough chances can become more important. Against enemies with a heavier allotment of anti-armor or mixed-use weapons, then armor becomes a more costly proposition.

The armored infantry takes twice as many rounds of incoming fire to wipe out. So back on supplies, they're placing more stress on the enemy GSP. They take half the proportionate losses in any given round, so they produce a better Cohesion Rating making them harder to Breakthrough against.

I think their longer endurance can provide better protection of high-value units, since it's not uncommon for such units to survive better and die late after the infantry has been cleared out around them, but this might be deceptive, I'd need to run the math. It's certainly sometimes true though - if the enemy isn't using Front Line Attack, their units can't hit your units behind the front line, so the armored infantry does a significantly better job of protecting a support-line stack of Light Bombardment in a trench stalemate situation.

This is true per ton, but not per BP. Which ties back to the tonnage efficiency point as the chief advantage (the relative lower GSP use of the armored formation, depending on weapon types, is also in play but the effect is much smaller).

[Ulzgoroth]

The former have twice as many built-in GSP worth of supplies, so if you're skimping on resupply units they can do more before stalling (though that becomes negligible if you're bringing plenty of supplies).

This isn't true. The former formation has twice as much GSP but they use it twice as fast. In fact, the latter formation has the (small) advantage here since they require half as many supplies, thus only half as much BP dedicated to resupply units.

Yes it is. The former has twice as much GSP and use it twice as fast, so it lasts the same amount of time, yes. But they do twice as much shooting in that time! Unless they die off too fast, anyway.

The armored infantry takes twice as many rounds of incoming fire to wipe out. So back on supplies, they're placing more stress on the enemy GSP. They take half the proportionate losses in any given round, so they produce a better Cohesion Rating making them harder to Breakthrough against.

I think their longer endurance can provide better protection of high-value units, since it's not uncommon for such units to survive better and die late after the infantry has been cleared out around them, but this might be deceptive, I'd need to run the math. It's certainly sometimes true though - if the enemy isn't using Front Line Attack, their units can't hit your units behind the front line, so the armored infantry does a significantly better job of protecting a support-line stack of Light Bombardment in a trench stalemate situation.

This is true per ton, but not per BP. Which ties back to the tonnage efficiency point as the chief advantage (the relative lower GSP use of the armored formation, depending on weapon types, is also in play but the effect is much smaller).

No, it is true per BP. What I was said is true about the forces specifically presented: 2500 HPA infantry vs 5000 basic infantry, with unspecified but presumably identical weapons. So long as you presume the incoming attacks don't have more AP than the basic infantry armor, as we've both noted.

1 armored unit costs 2 unarmored units, but takes 4 hits to kill (statistically, obviously) so the smaller but equally expensive force endures twice as much light weapons fire before being destroyed.

[nuclearslurpee]

You're right on both points as I misunderstood the intention.

[Ulzgoroth]

Unarmored infantry are the most cost-effective unit type, but of course easily the most transport-ineffective.

An extension of this I find interesting - we've been explicitly talking about infantry, but all the same factors apply to other unit types too. Even if you're building heavy vehicles, you always have the option to give them light armor and doing so won't hurt their per-BP exchange value and (depending on threat context) may improve it.

Going to a weird place to look at the idea that infantry are the most cost-effective unit type, let me travel to the land where everyone uses PW-equivalent weapons. I'm going to also focus explicitly on the metric of effective shots outgoing time expected hits to kill which we've been more or less speaking to but not calling out.

HEV with 2xCAP and light armor at 60 tons per unit (and a cost of 120 tons since they're armor 2) deal out 12 shots and take 4*36 = 144 hits. (On the attack, comparing against infantry, we should treat that as 25% less to account for the difference in hit modifier, so call it 108 with a product of 1296.) 120 tons of PW infantry only give and take 24 shots for a product of 576 - overwhelming advantage in performance to the vehicle per BP! Looking at alternative weapons, 120 tons of CAP infantry dish out 60 shots but only take 10 hits - putting them slightly ahead of the PW infantry in the product metric though they've got the life expectancy of a mayfly on the surface of the sun. Branching out beyond the original premise to PWL we get up to 40 hits - and 40 shots that are 1/16th value each, for a miserable product of 100. (These guys have value, but ability to mix it up with peer-level opposition isn't it.) 120 tons of PWI on the other hand, takes 20 and gives 20, but their outgoing are worth 25/16 each assuming a worthy target (like the tank), so they get a product of 625, the best score so far for the infantry but still only half what the tank delivered! For the final utter abandonment of the land of PW, LAV infantry are mathematically awkward at 7.5 units to 120 tons, giving and taking one each but with attacks worth 36 standard shots against a worthy target, they come to an eye-popping product of 2025...but of course only a pitiful 56.25 against targets that don't reward their specialization. (900 against light vehicles, which is still better than small arms though a large step down. Only 506.25 against light armored static targets, so at that point you'd be better off with small arms!)

(Supplemental: Light Bombardment comes in looking quite bad at only 432 against targets where their 2x damage counts and a lousy 108 where it doesn't. However, they've got the option of getting somebody less expensive to do their dying for them, which takes them out of the frame of the metric. That said against targets with 1x HP they contribute less firepower per ton than PW or PWI in addition to being no good at taking hits...don't bring a mortar to an infantry fight?)

Particularly surprising to me in all that - even on the defense instead of attack, where the infantry has the benefit of twice as much max entrenchment as vehicles, the HEV's modified product would still be 864, beating out any of the small-arms infantry. Heavier elements on garrison duty have merit! Though CAP static (5 24 ton units) at 30 shots and 45 hits and no entrenchment comparison penalty for a product of 1350 beats the HEV's efficiency.


Tangential to the ground fighting, I'd note that while armor increases the BP cost of STO weapons as usual, it has a negligible impact on their substantial mineral cost.

[deathpickle (OP)]

One thing i've found a little harder to appreciate is the differences in efficiency from using bigger weapons. For example, heavy crew served infantry are actually worse vs crew served infantry, even when they have armor. But a heavy crew served vehicle wins better than a regular crew served vehicle vs that same infantry! Very surprising result.

In terms of base unfortified strength, NO vehicle with crew served heavy or otherwise beats an infantry with light anti-vehicle.

its funny after building the whole machine, all I feel now is just eh, i don't care anymore, i'll build the army I think looks cool. In the end it all works.

[nuclearslurpee]

its funny after building the whole machine, all I feel now is just eh, i don't care anymore, i'll build the army I think looks cool. In the end it all works.

This is generally the case.    A lot of the nitty-gritty micro-details in practice end up depending too much on what the opponent has, and there's no way to find that out besides reconnaissance in force, so you may as well make the army you like while you're waiting.