The Logistics of Planetary Invasions: A Mechanistic Analysis

[nuclearslurpee (OP)]

This post was originally going to be an EffortPost™ in the Suggestions subforum, but it got complicated and frankly more interesting than I expected, so instead I am posting it as a mechanics post. This post was originally motivated by complaints made in the Bugs Thread that planetary invasions were fundamentally broken and unfun as a gameplay mechanic. I wanted to analyze the mechanics of invasions, initially to serve as the basis for suggestions to improve invasions. However, things quickly became complicated, and in the process I learned some things which led me to rethink planetary invasions and to question the initial premise - are planetary invasions in fact broken and unfun gameplay?

The basic idea here is to analyze what it actually takes to carry out a planetary invasion, in an effort to quantitatively assess the complaints many people have about planetary invasions being too prohibitive and/or unfun gameplay. My hope is to accomplish a few things here: (1) to provide something generally-informative for the player base, (2) to give some insights on how to effectively go about playing your game to prepare for eventual planetary warfare, and (3) to gain some insightful basis for looking at the question of whether or not planetary invasions are actually problematic or poor game design.

In a broad sense, a planetary invasion consists of four stages: (i) building a lot of troops, (ii) shipping them to the nearest NPR homeworld, (iii) shooting things, and (iv) maintaining supply lines until the battle is over. Of these, step (ii) is fairly well-understood and I'm not going to spend much time on it, as I think most players know how to build 200,000-ton assault dropships and point them at the enemy. I'm also not going to cover the naval aspects such as eliminating STOs or conducting preliminary orbital bombardments, as I think most players know how to point and shoot. The remaining aspects, however, correlate with common complaints which are raised about planetary invasions, thus are worth analyzing in detail to assess the validity of those complaints - and what, if anything, can be done to mitigate those issues which so many players struggle with.

Without further ado, we begin with...

Building Ground Forces

To get a sense of how long it actually takes to build the several million tons of ground troops we need to go conquer someone, let's make some simplifying assumptions:

• The build cost of a ground formation is very nearly (neglecting HQs) equal to the size of the formation in HS (tons/50) times the average armor level of the elements in that formation. A 5,000-ton battalion of infantry (1 armor) costs about 100 BP to build, while 5,000 tons of medium tanks (4 armor) costs 400 BP. I'm going to assume that the balance of infantry and armor in our army is such that the average armor level is 2, so that every 5,000 tons of ground forces will cost 200 BP.
• Ground Force Training Facilities (GFTFs) start off with 250 BP/year capacity, if I recall correctly, and the techs to improve this are relatively cheap. I will assume an average of 500 BP/year tech level which I think is reasonable for the early game (say, first 25-50 years).
• A GFTF costs 2400 BP to build with planetary industry. At the start of a typical 500m pop game (the default), the player race has 400 factories producing 4000 BP/year, so if a player gives 20% of their industry to GFTF construction (an optimistic estimate, but we'll go with it) they can build a new facility every 3 years. Of course this can be accelerated with technology, new factory construction, and good planetary governors, all of which are difficult to model in a simple way, so I'm going to make a rough approximation that we build a new GFTF every two years on average.
• Assuming a default 500m pop start, we begin the game with 4 GFTFs in service.

This means that we generate a total of (based on our assumptions) 4000 BP in the first two years, 5000 BP the next two years (9000 total), and so on. After ten years we have produced 30,000 BP of ground forces, after 25 years we will have built 122,000 BP, and after 50 years a nice 400,000 BP. Again, rough estimates here.

Recalling that our assumptions give us 25 tons of ground forces per BP, this means that after ten years we can build 750,000 tons of ground forces. After 25 years we can build 3,050,000 tons, and after 50 years we can have an impressive ten million tons of ground forces. Now I do want to emphasize that I am making some fairly generous assumptions here, but in any case it looks like we should be able to build a nice, big invasion army in 25 to 50 years - of course, this neglects the need to, for example, upgrade old formations with new equipment, or to build enough garrisons and defensive troops to secure our expanding stellar empire. But don't bother me with trifles, we have a 10,000,000-ton invasion army and I am going to use it!

Note that an important part of this assessment is that we actually build a lot more GFTFs. If I had only used my initial four facilities, and not built any more (because I had more important things to build like, I dunno, mines or labs or whatever), I would only be able to produce 100,000 BP of troops - a "mere" 2.5 million tons - in 50 years. That's nothing to sneeze at, but it's also not terribly impressive when trying to invade a planet defended by multimillion tons of enemy ground troops.

Shooting the Other Guy's Ground Forces, Repeatedly and with Great Vigor

So I've found a nearby NPR, blown up their ships, shot all their STOs from orbit, and shuttled ten million tons of troops to the planet surface in dropships. However, the local NPR has decided to fight me instead of surrendering, and this is going to take a while.

To find out how long this war is actually going to take, we need to somehow estimate the casualty rates with math. As it happens, we have a reasonable way to estimate this in the form of Lanchester's Law, which takes the form of:

Code: [Select]

dA / dt = -beta * B

dB / dt = -alpha * A

Terms:
  A : Strength of Force A (attackers), here in units of tons
  B: Strength of Force B (defenders), here in units of tons
  alpha: Kill rate of Force A firing at Force B
  beta: Kill rate of Force B firing at Force A
  t: time, here in units of ground combat increments (GCI)

This system of equations can be solved to obtain a rather unwieldy expression for the time dependence of A and B, or integrated numerically; in either case, the results are not much different at least in the case of Aurora.

The kill rates are essentially the product of the hit rate, the average shots per ton, the probability of scoring a kill when a shot hits, and the average tonnage destroyed per kill. The hit rate is generally known, except for commander bonuses. For the attackers, the hit rate is the product of the base 20% hit rate and the terrain to-hit modifier, divided by the effective fortification modifier; for the sake of example, I will use Mountain terrain, which has a fortification modifier of 2x and a to-hit modifier of 0.5x, and assume the defending force includes INF and STA elements as well as enough CON to bring the entire force to a maximum fortification of 6x (12x with terrain modifier), giving an estimated hit rate of 0.833%. For the defenders, the hit rate is the product of the base 20% hit rate, the terrain to-hit modifier, and the effective evasion stat of the attacking force which I will assume to be 0.6x (INF and VEH elements), giving an estimated hit rate of 6.0%. I will further assume that the average shots per ton is 0.2, taking this as representative for a mix of PW (0.2), CAP (0.5), and MAV (0.03) weapons, and that the kill probability for a hit is 50%, which is a fair approximation if both forces are made up of an even split by tonnage between infantry and armored elements. Finally, making the same approximation about force composition, I estimate the tonnage destroyed per kill at about 10 tons. This gives values of alpha = 0.00833 and beta = 0.06.

Now let's take my big, impressive 10,000,000-ton army and land it on the planet of my local NPR opponent, the Haplessians, who only have 2,000,000 troops to defend themselves with, and see what happens:



So we will win handily, and it will take us less than ten days to do so. The time it takes to win is important, as discussed below, because it will directly influence how many supplies we will need to build to accompany our army.

Before we move on, I would like to try a few other cases:

(1) What if we invade with, say, 5,000,000 tons of troops? For reasons to be discussed below, this is a relevant question as we may not be able to deploy all 10,000,000 tons of the troops we've built as combat forces (we will need some logistics). In this case, we...okay, actually, we would lose horribly. But if we attack with 5,500,000 tons of troops, we can still win, but it will take us much longer, about a month (100 GCI = about 30 days), and we will lose most of our army in the process.



(2) What if the enemy has a nice, rolling prairie planet with few if any natural defenses (fortification modifier 1.0x, to-hit modifier 1.0x)? Surely it will be easy to kill them even with only five million tons of troops? Under these conditions, we have alpha = 0.33%, beta = 1.2%, and as it turns out we can now comfortably destroy our enemies with only moderate losses. We could even win with a mere four million tons of troops, if we really needed to, but with very high casualties. This takes only about five days.



(3) On the other hand, what if the enemy has a harsh, foreboding Jungle Mountains homeworld? With a fortification modifier of 3x and a to-hit modifier of 0.125x (alpha = 0.000139, beta = 0.0015) there's no way we can take this planet with five million soldiers...what about ten million? As it turns out, the answer is yes, but it will take about two months.



Okay, okay, that's enough math for now. So far, what we've learned today is that if we outnumber the enemy badly enough (for the curious, this condition is met when alpha * A^2 > beta * B^2 initially), we can take their planet from them. It might take fifty years to build a big enough army to do this, but it can be done. However, there is one other major consideration we need to deal with.

Supplying Ground Forces

Ground elements have a GSP value, which is determined by their weapons and indicates how many supplies that unit needs to fight ten rounds of combat (3 1/3 days). Therefore, for every 10 GCI while we are engaged against the Haplessians, we will need some amount of LOG to sustain our troops.

As a very rough estimate, I have found that for my own combat formations the total GSP for all elements in a formation tends to be about 30% of the tonnage - in other words, a 5,000-ton battalion will carry about 1,500 GSP. Extrapolating this recklessly, our ten million ton army will require 3m GSP every 10 GCI, or since one month is 90 GCI about 27m GSP per month.

We have two options to provide this GSP. We can use INF logistics units, which provide 10 GSP per ton or, more importantly, 500 GSP per build point as long as we don't slap any power armor on them. However, these can only resupply the formations they are attached to, meaning our front line formations will be less combat-effective per ton, and are vulnerable to enemy fire on the front lines. Fortunately, with the new unit series and replacement mechanics we can manage the supply situation reasonably well with these. The other option are LVH+LOG, which are logistically much easier to use (just slap them into an Army-level HQ and let them do their jobs), but provide only 8 GSP per ton due to the LVH tonnage overhead, and even worse provide only 200 GSP per build point because they are an armored unit! This may end up being a serious problem if we need to build a lot of supply elements to keep our offensive moving.

Returning to our big, scary army, which demands 27,000,000 GSP per month: with infantry logistics elements this comes out to 54,000 BP needed to supply our offensive, just for one month. Remember that our total ground forces BP over the past 50 years has been a whopping 400,000. We will need more than one-eighth of this just to keep our army supplied for one month.

Now, remember our initial invasion plan of Haplessian Prime, in which our ten million tons of soldiers could defeat two million tons of enemy soldiers in ten days? We will need 18,000 BP worth of logistics elements to keep our soldiers in supply for that time period, which isn't too bad actually. On the other hand, if we were to send only 5 million tons of soldiers, we would need half as many supplies per month (13,500,000 GSP per month, or 27,000 BP) but we would actually need supplies for a whole month. However, we only built half as many soldiers in the first place, so the overall cost in BP is lower (the cost to replace all of our losses, however...).

The extreme case, however, would be our assault into the Jungle Mountain terrain, which requires supplying our ten million tons of troops for nearly two months - requiring roughly 100,000 BP of supplies on top of the 400,000 BP we used to build our army. That's a lot to put it bluntly, however do we really need that many supplies? Consider the following:

• The defending force will have the same problem - they, too, will run out of supplies unless they have dedicated 30% of their production to logistics, which at the very least no NPR ever does as far as I know.
• Formations which are "out of supplies" are not combat-ineffective - they will still fight, but each element will have only a 25% chance to fire in each GCI.

Therefore, we really only need enough supplies to at least match the defending force, and once both forces have run out of supplies they will continue fighting on equal footing at a much lower intensity - the net effect here is that out invasion will take roughly four times longer than we had initially planned. If we really want to splurge, we can try to land on the planet with more supplies than the defenders have, which gives us more GCI of full-efficiency fighting while the defender is only at 25% efficiency, potentially allowing us to gain a big advantage. This point would become more important if we had a smaller force (at equal tech, we need around 6,600,000 tons to break even), in which case the battle would take much longer.

All this being said, having ~20-25% of our force composition as logistics elements is not too onerous, one might even say it is realistic. I have also neglected the fact that supply demands will decrease as we lose troops, which further reduces the actual needs.

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So to conclude, let's return to my earlier stated goals:

(1) What information has been provided to the player base? First of all, with a reasonable investment into ground forces (which is, as we have seen, very necessary if you want to mount a planetary invasion), a player can build roughly ten million tons of ground forces over a 50-year period. This would scale approximately linearly with the starting population at least within a reasonable range. Further, a planetary invasion under relatively favorable conditions will still require multiple months to complete, and under more marginal conditions can take a year or more. Finally, to execute a planetary invasion can impose a significant logistics burden, but as a fraction of our total force composition it turns out to not be too onerous under most conditions.

(2) What helpful insights have we gained for conducting planetary invasions? Aside from basic conclusions such as "build a lot of troops" and "build a lot of logistics elements", this requires some interpretation of the data. One major takeaway here is to maintain a significant technological advantage. Because the kill rate scales roughly quartically with technology - i.e., as (attack / armor) ^ 4 - a tech edge has a very strong effect. In practice, this is less likely to improve your own kill rate very much if you are starting from equal tech compared to your opponent, because of overmatching effects, however if you have better armor than your opponent's weapons their own kill rate will drop off dramatically, which allows you to (a) use fewer troops, and/or (b) prosecute a campaign with poorly-supplied troops, since being out of GSP only reduces your damage output by 75% (since out-of-supply formations only have 25% of their units firing in any GCI).

This is an important point, since as we have seen, in some extreme cases it may be untenable to keep an invasion force supplied for the duration of an invasion, although in our favor, the defenders will have the same problem - the net effect of this is most likely going to be an extreme lengthening of the campaign by a factor of ~4x. And now we know why the game is called "Aurora 4x"! rimshot 

Additionally, the role of orbital bombardment can be considered in quantitative terms. We can estimate the level of enemy forces we can comfortably defeat with our own forces, and attempt to orbitally bombard the enemy down to that number. This will still inflict some collateral damage, but hopefully less than just nuking them to zero from orbit, leaving something for our boots on the ground to conquer.

(3) Are planetary invasions fundamentally broken?

This is a difficult question to answer. In most cases, the answer seems to be "no" since aside from requiring a lot of troops the burden on the attacker is not too extreme in terms of e.g. supply requirements. In some cases, such as attacking with marginal forces or into harsh terrain, the supply requirements can be significant; however, as we have seen, this is not as problematic as it appears, because we really only need enough supplies to last until the defenders run out of supplies, at which point we are fighting on even footing just at a lower intensity. This leads us to realize that the purpose of providing an invasion force with extra LOG elements is not to keep them supplied indefinitely, but only to keep them on even footing with the defenders, or perhaps to gain a brief advantage which can snowball into a big victory.

In these extreme cases, we may be subjected to multiple months (or even years?) of 8-hour increments even if we have nothing else going on in our empire and would really rather be clicking the five-day button. Is this a problem? Well...maybe not? Aurora after all has always been a game for patient people, dating back to the VB6 days of hitting "next turn" and grabbing a good book to read for the next few minutes. In all honesty, it is pretty likely that by the time you're mounting a planetary invasion (remember, 50 years to build all of these troops...), your empire will be busy enough that something is happening most of the time - frankly, I recommend turning your construction increment down to one day or even eight hours so that you have something to do after every few button clicks.

So with the logistics problems settled reasonably, and the problem of eight-hour increments for months or years of game time admittedly handwaved with exhortations to patience and serenity, what else is left? Some people will complain about the amount of troops required, or how long it takes to build them. There is some merit to this, perhaps, but at the same time Aurora is fundamentally a game about the long-term, and the player frankly should be punished or rewarded for having the foresight to plan several decades into the future. It is ultimately a question of taste, but personally I do not see a problem with this aspect of the game design aside from my own impatience, and for those who do take issue we have SpaceMaster mode.

I will, however, note one important caveat here, which is that the enemy can also build ground forces. This is, in theory, a problem, as an alien race can simply build enough troops to match an invasion force (given the foresight to do so well in advance, of course), thus effecting a stalemate at the strategic level. In practice, however, a race consigned to their homeworld by a superior power will eventually fall behind, as they will be starved of the TNEs needed to build research labs to develop better technologies as well as GFTFs to keep up with the production of their enemy, not to mention eventually running out of the Vendarite needed to build any troops in the first place. More pragmatically, of course, the NPRs just don't build up their defenses that well anyways, so with dedication and focus the player can rather easily outbuild most NPRs which precludes much of the issue anyways. Where multiple player races are concerned, it is up to the player to devise a solution that they personally find most satisfying.

So to answer the question: No, I do not believe that planetary invasions are fundamentally broken. They do, however, require the player to break out of certain misconceptions and rely on very astute long-term planning to actually make them possible. Hopefully, this post has contributed in some way to help players do exactly that.

Have fun shooting things, folks!

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EDIT: I have corrected some errors in the kill rates due to neglecting the tonnage-per-kill term. This significantly changes the analysis compared to the first version of this post, since campaigns take much less time and supplying armies thus is much more feasible. Please be aware of this when referencing the earlier points of discussion.

[Zap0]

What an EffortPost™! Your dedication to illuminating the mysteries of Aurora is greatly appreciated.

For the defenders, the hit rate is the product of the base 20% hit rate, the terrain to-hit modifier, and the effective evasion stat of the attacking force which I will assume to be 0.6x (INF and VEH elements), giving an estimated hit rate of 6.0%.

You mean the attackers here in this one since it's about evasion and seeing as the last sentence talked about the defenders already. Given that we're talking about campaigns in the realm of months, maybe we shouldn't just consider the scenario of all attackers being set to frontline attack, but just frontline defense and have them build up their own fortification. It only takes 30 days for a unit to reach it's max self-fortification as per the rules post and I've just tested that units do gain fortification while engaged in combat. Only taking 1/3 hits after a month may be better than taking 60% of fire all the time, but the part at the start where you take every shot may snowball into not as much of an advantage. Perhaps wait out the enemy's supply on frontline attack, then switch to building your own fortifications?

At what point would it be worth it to bring construction vehicles in your attacking force? More worth it than the same amount of BP logistics?

There is also the BP cost of troop transports to consider. Dropships, if you're not shooting every STO from orbit (which would probably already diminish the planet value greatly) 10m tons of troops require a lot of ship to move. I can also envision scenarios where you can only move 2m tons of troops at a time and so drop another 2m on the enemy planet every month or few weeks.

What do the collateral damage numbers on these months of fighting look like? Is it even worth doing ground invasions at this scale, or will everything on the planet just get destroyed anyway?

In general I like that fights can take months as that can allow a besieged planet to hold out until the situation in orbit changes, although I'm not looking forward to 8 hour increments and infinite log spam for that long.

As far as broken goes, I'm in favor of calling it that. The numbers involved in these kinds of scenarios are an order of a magnitude too large for my taste, with what millions of tons of troops and decades to build up a force, not to mention the supply insanity. Buffing the supply vehicle seems like an easy first step, I never realized it was so inferior BP-wise.

[Agraelgrimm]

Ok, considering that i am doing graduation in logistics in RL, this post is a lot of fun to have. However that will take some time to make an in depth analysis and give my 2 cents on it. What i can do right is to point out that all those tons of supplies that you *think* you need to keep the invasion going for lets say a minimun period of 3 months is actually way less. How so? Well, you have attrition loses. Meaning that every tick you will lose an X amount of troops, these troops will not be using further supplies since they are dead, so if we imagine that the invasion will last 1 year, you will probably lose about 20% of your troops in the first 2 months. Meaning 20% less supplies to be used to keep the invasion going.

You will spend some supplies for that, will have to account of logi units lost by bombardment and so on, so forth, and of those, you have to consider the amount of troops you will spare using construction units to further reinforce your ground troops to mitigate damage to the logistics units, then after all that we can kinda make a preditcion and over that as a rule of thumb we either increase 2 times what we *think* we need or we get to the logic conclusion that logistics units should be dropped from orbit procedually to prevent losses trough bombardment and further spare us from brain breaking calculations and predictions.

But in all likelyhood the only scenario we should prepare for is the one where we win but by serious attrition because if everything goes well we are equipped for that and if the enemy is stronger than us, then we are dead. If we are able to reinforce the ground forces to tick the balance, then we go back to the one where we win trough serious attrition.

[Agraelgrimm]

What an EffortPost™! Your dedication to illuminating the mysteries of Aurora is greatly appreciated.

You mean the attackers here in this one since it's about evasion and seeing as the last sentence talked about the defenders already. Given that we're talking about campaigns in the realm of months, maybe we shouldn't just consider the scenario of all attackers being set to frontline attack, but just frontline defense and have them build up their own fortification. It only takes 30 days for a unit to reach it's max self-fortification as per the rules post and I've just tested that units do gain fortification while engaged in combat. Only taking 1/3 hits after a month may be better than taking 60% of fire all the time, but the part at the start where you take every shot may snowball into not as much of an advantage. Perhaps wait out the enemy's supply on frontline attack, then switch to building your own fortifications?

At what point would it be worth it to bring construction vehicles in your attacking force? More worth it than the same amount of BP logistics?

There is also the BP cost of troop transports to consider. Dropships, if you're not shooting every STO from orbit (which would probably already diminish the planet value greatly) 10m tons of troops require a lot of ship to move. I can also envision scenarios where you can only move 2m tons of troops at a time and so drop another 2m on the enemy planet every month or few weeks.

What do the collateral damage numbers on these months of fighting look like? Is it even worth doing ground invasions at this scale, or will everything on the planet just get destroyed anyway?

In general I like that fights can take months as that can allow a besieged planet to hold out until the situation in orbit changes, although I'm not looking forward to 8 hour increments and infinite log spam for that long.

As far as broken goes, I'm in favor of calling it that. The numbers involved in these kinds of scenarios are an order of a magnitude too large for my taste, with what millions of tons of troops and decades to build up a force, not to mention the supply insanity. Buffing the supply vehicle seems like an easy first step, I never realized it was so inferior BP-wise.

The amount of BPs we should put on Ground Units is proportional to the wish we have to avoid collateral damage to logistics units as said in the post i've made. I would also suggest of keeping logi units on orbit but with vehicles alongside them, meaning that we can tip the balance of the battle in any given point if we consider the amount of damage that we would be able to make by dropping certain troops after the enemy have taken certain losses like 30-40% of their AT capabilities. If we want to make it viable to finish those battles in a fashion manner,  tactics will have to be used to not only prevent a lengthy conflict, but unnecessary losses in both GU and LOGI units.

Not only we have to consider the BP on dropships but also on support ships, orbital bombardment support and fighters that could be fitted with a single pod for that secondary capability of ground support. Is either this or nuclear bombardment of the atmosphere wich is sub-optimal. And we have to remember that we can use Fighter CP for that, so we can increase the amount of damage our army make in the course of those 25-50 years making the need to use supplies diminish for each part of support we add to our calculations. And yes, all of this matters a lot if we want to predict how much supplies we should make. It could be the difference from a few millions to under one million easy.

Not only all that, but the amount of Support Fighters and Ship's weapons we have to provide fire support can further increase the amount of enemy vehicles and AT units that are present in the surface making our own heavy vehicles being more efficient and etc. Disabling the enemy's Long Range Bombardment units in the start of the conflict will make it so we can decrease the amount of time we spend in the war plus making sure each additional logistical unit we drop will be able to make further damage to their formations.

[nuclearslurpee (OP)]

Quick post to note that I've corrected a few errors I made in calculating the logistics requirements. The overall conclusions do not change too substantially but the logistics burden becomes noticeably less extreme when you don't accidentally add an extra zero...amazing, I know.

Will reply to the substantive commentary tomorrow.

[Garfunkel]

Supply vehicles have a chance of "surviving" being eaten. On a sufficiently large scale, it might have an effect, though I have no idea of how to calculate for that.

[Jorgen_CAB]

There are a few things we need to consider in terms of combat that is very important... infantry consume much less supplies than tanks for example.

The thing that makes the ground combat "broken" for me is that you have no incentive to use combined arms warfare in the normal sense.

As a defender all you want to do is basically to kill the enemy infantry or and the their vehicles with anti-infantry weapons as the attacker you want to do the same. This means you always hold anti-armour units back to save supplies until sufficient numbers of enemy infantry is gone as to not waste your high supply anti-armour shots.

This means that constructing your realistic tanks with both CAP and anti-armour weapons is extremely inefficient in the game for this reason and managing your logistical cost is very important to keep your killing power as high as possible for as low a logistical cost as possible. It also means allot of micro management, not to mention it becomes gamy against the NPR to do this as well.

What is "broken" is that the game promotes more unrealistic combat strategies.

Another thing is attack and defence... as the attacker you can just set your entire formation in reserve and just wait until your entire force is as entrenched as the defenders and then attack them on equal footing. This is also an imbalance as the defenders need to give up their defensive bonuses to attack you and then you both fight on equal footing again.

As I like multi-faction games there is no way to defend if two factions have settlement in the same body, there are no real concept of defence. As a player you have to simulate this by restricting forces to reserve versus defence and attacking lines accordingly to give the impression that there is a defence and attack concept.

Another issue is that you can probably also make a case that you don't use logistics for anything than your initial assault where you engage enemy infantry, after this you might as well just fight without supply as long as you have the numbers this is more efficient, you just bring more tanks (or infantry shield) rather than supplies instead as the opponent will not kill them fast enough so it is cheaper than loosing supplies. The tank/infantry losses become your supplies...

[Jorgen_CAB]

Even worse I think is that the current version of ground combat give incentive to put all anti-armour forces in their own fighting formation with no logistics on the at all and only give logistics to your anti-infantry forces. Once the enemy infantry is dealt with you can withdraw logistics from your infantry as well and just allow attrition destroy the rest of the enemy armoured forces, no logistics needed at all for them at that point as infantry are quite cheap as is and can be used as LOG point at this stage.

[Bremen]

Another thing is attack and defence... as the attacker you can just set your entire formation in reserve and just wait until your entire force is as entrenched as the defenders and then attack them on equal footing. This is also an imbalance as the defenders need to give up their defensive bonuses to attack you and then you both fight on equal footing again.

If I understand the system correctly, isn't the solution here just to place one formation (ideally vehicles of some sort) on attack? If every enemy unit is in reserve, then your unit gets to attack them without return fire, and if they set anything on defensive then the rest of your force can engage it with the full benefit of fortification. It's not really practical to fortify up over several months while being constantly hit by even a small unit.

That's why I like to include a small formation of light vehicles with even my more defensive oriented forces. Lore wise, they're raiders and recon, but mechanically they keep an enemy honest by making sure they can't do the everything in reserve trick.

[Jorgen_CAB]

Another thing is attack and defence... as the attacker you can just set your entire formation in reserve and just wait until your entire force is as entrenched as the defenders and then attack them on equal footing. This is also an imbalance as the defenders need to give up their defensive bonuses to attack you and then you both fight on equal footing again.

If I understand the system correctly, isn't the solution here just to place one formation (ideally vehicles of some sort) on attack? If every enemy unit is in reserve, then your unit gets to attack them without return fire, and if they set anything on defensive then the rest of your force can engage it with the full benefit of fortification. It's not really practical to fortify up over several months while being constantly hit by even a small unit.

That's why I like to include a small formation of light vehicles with even my more defensive oriented forces. Lore wise, they're raiders and recon, but mechanically they keep an enemy honest by making sure they can't do the everything in reserve trick.

The NPR are not likely to do this and this depend entirely on the size of the battle and forces involved... if the attacking force is small enough it can certainly be worth the effort as you mainly are going to land infantry/static formations in that initial stage the stakes are not very high.

[nuclearslurpee (OP)]

Hi folks:

I have corrected some errors in the kill rates due to neglecting the tonnage-per-kill term. This significantly changes the analysis compared to the first version of this post, since campaigns take much less time and supplying armies thus is much more feasible. Please be aware of this when referencing the earlier points of discussion in the comments.

I will note that this does make the kill rates seem a bit high compared to what people tend to report when they complain about the pace of ground combat and planetary invasions. I don't have an immediate answer for this, other than to note that validation of my models probably would require some test games which I don't have time to do presently. Any thoughts on the matter are of course welcome, and anyone who does have time and the interest in conducting such tests is welcome to do so and let us all know how it goes.

Comment responses:

Given that we're talking about campaigns in the realm of months, maybe we shouldn't just consider the scenario of all attackers being set to frontline attack, but just frontline defense and have them build up their own fortification. It only takes 30 days for a unit to reach it's max self-fortification as per the rules post and I've just tested that units do gain fortification while engaged in combat. Only taking 1/3 hits after a month may be better than taking 60% of fire all the time, but the part at the start where you take every shot may snowball into not as much of an advantage. Perhaps wait out the enemy's supply on frontline attack, then switch to building your own fortifications?

[...]

As far as broken goes, I'm in favor of calling it that. The numbers involved in these kinds of scenarios are an order of a magnitude too large for my taste, with what millions of tons of troops and decades to build up a force, not to mention the supply insanity. Buffing the supply vehicle seems like an easy first step, I never realized it was so inferior BP-wise.

Per my revisions the situation is much less dire compared to the original version of my analysis. Notably supply vehicles are not as poor as I initially assessed, and with a properly superior force the fight can actually take less than a month in many cases.

Ok, considering that i am doing graduation in logistics in RL, this post is a lot of fun to have. However that will take some time to make an in depth analysis and give my 2 cents on it. What i can do right is to point out that all those tons of supplies that you *think* you need to keep the invasion going for lets say a minimun period of 3 months is actually way less. How so? Well, you have attrition loses. Meaning that every tick you will lose an X amount of troops, these troops will not be using further supplies since they are dead, so if we imagine that the invasion will last 1 year, you will probably lose about 20% of your troops in the first 2 months. Meaning 20% less supplies to be used to keep the invasion going.

I've amended by OP to note this, although since I am mainly interested in a first estimate to guide planning for an invasion (far too many approximations are made to call this "accurate"!), I think it is okay to leave this off. It is always better to have extra supplies than not enough.

What do the collateral damage numbers on these months of fighting look like? Is it even worth doing ground invasions at this scale, or will everything on the planet just get destroyed anyway?

The amount of BPs we should put on Ground Units is proportional to the wish we have to avoid collateral damage to logistics units as said in the post i've made.
[/quote]

I admit that I don't really know the collateral damage impact. It is difficult to assess as it is tied closely to the weapons used by both forces, the actual number of installations on a planet, and the use of orbital bombardment e.g. to eliminate STOs. I may look at it in the future.

Supply vehicles have a chance of "surviving" being eaten. On a sufficiently large scale, it might have an effect, though I have no idea of how to calculate for that.

I believe at the large scale the mechanic is tuned to match the GSP requirements of a formation, so the only effect would be from commander bonuses which I am not including here.

There are a few things we need to consider in terms of combat that is very important... infantry consume much less supplies than tanks for example.

[...]

Fair points which have been raised in previous discussion. However I do want to emphasize, my intention here is not to interrogate ground combat mechanics in the main, but only to investigate the feasibility of planetary invasions. Along these lines only, and following the current revision of my OP, I have found them to be generally feasible given proper preparation over many years.

As a general rule, in the realm of gamey tactics such as holding the entire attacking force in reserve or using small probing LVH formations to defeat this, as the NPRs don't do it and as the player I can choose not to, I am happy to leave that as a problem(?) for Steve to worry about.

----

Once again, I will remind everyone, with the revisions I've made to the analysis the picture now looks far more favorable for a ground invasion, with the major limit being the time and investment to build (and transport, as some have pointed out) a large invasion army and not, as previously feared, the demand for a lot of logistics (which even if so, is not as crippling as it first appears with Aurora's game mechanics). I strongly recommend checking out the revised analysis and the assumptions made before continuing the previous discussions!

[Garfunkel]

Thanks for the update and revision. To me it seems that the only problem with planetary invasions is that players underestimate how many tons they need. Which is an understandable issue because you build individual ships and it's only very late in the game that you have hundreds or thousands of ships (unless you play with fighters/FAC a lot) so the first instinct is to do the same with ground forces, in essence building a handful of small formations instead of an army of ten million tons.

[Jorgen_CAB]

This is also why you probably should avoid to build main armies at less than regiment size formations, larger formations also are more powerful than smaller formations.

I generally build "Army" formation as battalion/regiment size and "Marine" formations often become smaller formations as they conduct more specialised missions that don't require millions of tons of troops.

I also never game the system either... but I die a bit inside when I build a main battle tank with mixed weapons knowing it is a bad choice... 

[Droll]

For me the problem isn't actually the number of troops required, it is the amount of collateral damage that a balanced RP army will do.

Try adding any form of medium bombardment and above and you are going to realize that even when avoiding orbital bombardment, you will have very little left to conquer.
This problem becomes a non issue if you have much higher weapons tech than the enemies armor tech, since you will have less "wasted" shots to armor.

So for me, planetary invasions are only viable if I have massive tech advantage.

Although out of the scope of OPs post, the amount of micro in making in depth hierarchies is still very high and relevant to why people complain about "too many troops required".
The 1.13 field position check box is amazingly helpful, but since we cant create "sub-OOBs" making a division down to company level is still very time consuming, which inadvertently distorts the "long term planning". It would also be nice if we could specify the number of identical formations to be trained much like in SM mode "instant build". Finally, I want to mention that although it's an ok argument for the time increments, I don't accept the patience handwaving as an acceptable retort to the massive amounts of UI micro that is current required to RP in certain ways (no I am not making 1M ton regiments).

[nuclearslurpee (OP)]

Thanks for the update and revision. To me it seems that the only problem with planetary invasions is that players underestimate how many tons they need. Which is an understandable issue because you build individual ships and it's only very late in the game that you have hundreds or thousands of ships (unless you play with fighters/FAC a lot) so the first instinct is to do the same with ground forces, in essence building a handful of small formations instead of an army of ten million tons.

This is definitely true and I think something that the game in its current form does implicitly encourage to the detriment of players. In many rank systems the lowest ground commander rank is a Major-equivalent which suggests that companies should be the basic formation, but anyone trying to model these in-game quickly finds that they only add up to around 1500 tons. It was worse before 1.13 as the command limits for low-skill commanders would be in the few thousands of tons, when really to build and command multi-million ton armies you need base formations in the 20,000-50,000 ton range, really more of a regiment or brigade size. And of course anyone who played VB6 knows that battalions were the basic formation at the time...

A secondary issue I think is that players do underestimate the logistics they need (this is a general struggle, not confined to invasion contexts). The 18,000 BP of (infantry) logistics I mention for the invasion of Haplessian Prime comes out to a fairly impressive 900,000 tons (nearly 10% of our total force). Frankly I think that's a low amount compared to real-world military logistics (USAA BCTs for example have an astounding mass of logistics elements in their organizations), but even so I think many new players get in a mindset of just attaching "a few" logistics units to their formations and getting frustrated when they have to think about it in greater depth - certainly a large shift from VB6 when we had no logistics elements at all besides replacement battalions.

Ultimately, underestimating the number of troops and logistics elements needed has the net effect of causing a campaign to stretch out much longer than it "should", which I think is what generates a lot of the complaints - if players think a million tons is a huge army, and 10,000 tons of logistics is a lot, they are going to become rapidly disillusioned by the Haplessians.

For me the problem isn't actually the number of troops required, it is the amount of collateral damage that a balanced RP army will do.

Try adding any form of medium bombardment and above and you are going to realize that even when avoiding orbital bombardment, you will have very little left to conquer.
This problem becomes a non issue if you have much higher weapons tech than the enemies armor tech, since you will have less "wasted" shots to armor.

So for me, planetary invasions are only viable if I have massive tech advantage.

It sounds like this is an area worth looking at in greater detail to try and assess the actual rate of collateral damage. With some rough estimates at least we can suggest to Steve what sort of change could be made with minimal work required.

Although out of the scope of OPs post, the amount of micro in making in depth hierarchies is still very high and relevant to why people complain about "too many troops required".
The 1.13 field position check box is amazingly helpful, but since we cant create "sub-OOBs" making a division down to company level is still very time consuming, which inadvertently distorts the "long term planning". It would also be nice if we could specify the number of identical formations to be trained much like in SM mode "instant build". Finally, I want to mention that although it's an ok argument for the time increments, I don't accept the patience handwaving as an acceptable retort to the massive amounts of UI micro that is current required to RP in certain ways (no I am not making 1M ton regiments).

Please do note, I only mean the patience handwaving as an answer to the case of dealing with 8-hour increments for months (or years?) of game time. Micro is a different problem and, I generally will agree, one which we should desire to be minimized whenever possible without compromising the gameplay.

I agree that it would be nice to have much better means of managing large and detailed OOBs. However at the same time this is a consequence of one's RP - if a player wants to model down to company level, that is their decision and not one forced on them by the game. I do personally think that if one keeps their RP partially in their own imaginations, the system is not too onerous as it stands. For example, say I have an OOB constructed as follows:

   Corps (1m tons)
      Corps HQ @ 100k tons
      3x Division (300k tons)
         Division HQ @ 60k tons
         3x Brigade (80k tons)
            Brigade HQ @ 20k tons
            3x Regiment @ 20k tons

And then an invasion army consists of several corps adding up to however many millions of tons of troops I need, and I could add an Army HQ level at the several million tons if I had that high of a commander rank. Each Corps is 40 individual formations, and much of the micro work can be done as units are built by slotting them into the existing hierarchy a few at a time, setting support as needed, and so on, so that come the invasion all that really needs to be done is loading everyone up on ships and dropping them on Haplessian Prime. For this, I am willing to keep the battalions and companies under each regiment as a matter of headcanon, by which I mean drawing snazzy OOB graphics of them for my AAR. 

I will readily concede however that assigning ground support fighters/orbital support is a massive pain in the space rear end.