Odd yet interesting find regarding missile units

[Kobal2fr]

I had noticed odd battle results a few times, so in my last siege I made a specific test to better understand the behaviour of archers.

The result is that the formation missile units are in does not make a lick of difference per se. Wether in two wide lines or in 4 wide, 15 ranks long rectangles, archers, crossbows and muskets do NOT check for obstructions in their line of fire within their own unit.

What I mean is that, while each single archer in a given unit checks wether there's a building, tree, rock or friendly unit between him and his target, and arcs his shot accordingly, the other archers in his own unit are not taken into account. Archers in the back row fire straight through the previous ranks as long as they have an otherwise clean line of fire.

In other words : to an archer, the other archers in his own unit are translucent (and intangible).

It's of course very counter-intuitive, but it does make sense to a point : ranks in TW are all one-man-behind-the-other, while archer formations IRL would probably be more staggered, either checkerboard or diagonal... Anyway, my guess is that this is either an overlook in battleAI, or a conscious decision to avoid friendly-fire when on the move, for HAs especially.

Of course, using archers in box formations instead of long lines impacts their results, because their fire will be much more concentrated and focused (ie a 4 wide archer unit firing on a 15 wide spear unit will only target the 4 men in the middle), so there is still a point in having wide archer formations.

But it's something to keep in mind in siege situations for instance : if you have breached a gate/wall, sit your archers in front of it in 4x15 instead of 30x2, they'll be more accurate this way.

[Shahed]

So the deeper the formation the better for accuracy ?

I've noticed the same about archers firing through their teammates, only I was'nt too sure as i't's always happening very fast and you really have to sit and look at it.

[Kobal2fr]

Hmmm yes and no. On flat, unobstructed ground the accuracy is the same wether deep or thin. But when Line Of Sight is somehow obstructed (by walls, trees etc...) accuracy is better if you put more archers in the area where LOS is good.

I don't know if I'm being clear, so I'll whip out another of my artistic ASCII's

____XXXXXXXXXXX
____XXXXXXXXXXX
____XXXXXXXXXXX

======O-----O======

____AAACCCCAAAA
____AAACCCCAAAA
____AAACCCCAAAA

- is breached door
X is the enemy
A is an archer, C is an archer with a clean LOS


In this example, only the 12 C archers out of a total 33 will have a direct line of fire on the X unit, and only those 12 will fire right at them. The A archers will fire straight up and over the wall/towers and, more often than not, miss.

If you put them this way :

___XXXXXXXXXXX
___XXXXXXXXXXX
___XXXXXXXXXXX

====O------O======

______CCCC
______CCCC
______CCCC
______CCCC
______CCCC
______CCCC
______CCCC
______CCCC


Then all archers will fire straight and true. Losses in the X unit will not be much higher per volley, because all arrows will land on the same few men, but said losses will be much more consistent overtime, and you'll waste less ammo too.

[Shahed]

Got it.

[IsItStillThere]

Good tip, thanks!

I was having a hard time yesterday trying to get catapults to fire through a breached door...they were aiming at the center of a unit and hitting the wall instead.

[dismal]

Yes, the breached wall is an excellent example where you can see this behavior in action. It is my habit take out the towers and then march crossbows up to the breaches. For this, you want to put them in a longer narrow box.

If you watch them, you will see some shoot straight, some of them shoot up in the air, and some not shoot at all depending on whether they are blocked by the walls. You can see the line of demarcation fairly easily when the guys who are shooting squat to reload and the blocked guys stay standing.

The guys in the back of the box will still shoot straight if they are not blocked by the walls. Apparently, they are capable of shooting between the heads of the ranks in front of them.

[TheSeated]

Excellent find. This is a big deal. It's going to change the way people fight in SP and MP. I wonder if this works for muskets as well.

[Foz]

Of course, using archers in box formations instead of long lines impacts their results, because their fire will be much more concentrated and focused (ie a 4 wide archer unit firing on a 15 wide spear unit will only target the 4 men in the middle), so there is still a point in having wide archer formations.

So if a 4-wide unit of archers only targets the 4 men in the middle of the enemy line... then the widest your archers ever need to be is equal to the width of the unit they're firing at, as that assigns one full column of your archers to each man in the enemy front line, right? Do we know what happens when there are more archers in your line than in your enemy's front line? If the extra ones are arbitrarily assigned to the end man on the enemy line, then you actually achieve optimal fire by exactly matching the enemy's width. I'll illustrate:

____XXXXXXXXXX
____XXXXXXXXXX
____XXXXXXXXXX

____AAAAAAAAAA
____AAAAAAAAAA
____AAAAAAAAAA

Here A's are archers and X is their targets. This would be optimal firing position, as each enemy rank gets assigned 1 3-deep column of archers. I'm unclear whether archers target only the front line, or only the particular column of enemies, so for ease I'll just assume it's the front line that is targeted. It really doesn't make much difference for my purposes here. Here's how they look in a 2-deep formation vs. same enemy:


____XXXXXXXXXX
____XXXXXXXXXX
____YXXXXXXXXY

__LLAAAAAAAAAARRR
__LLAAAAAAAAAARRR

Here it seems that all the A archers will have a clearly defined X or Y enemy to shoot at. However, it's the L's and R's that I'm interested in, since they don't directly line up with any enemy rank. The most natural thing would seem to be to assign them to fire at the Y marked end units of the enemy line. This leaves only 2 archers to each X in the line, 6 on the left Y (2 A's plus 4 L's) and 8 on the right Y (2 A's plus 6 R's). This doesn't seem that bad, but if you analyze it empirically, you'll find that overloading end units with fire is a poor strategy. The right Y who gets shot at by 8 guys almost certainly dies, but possibly 3 or 4 times over, where those archers that scored hits could have killed 3 or 4 enemies if they were all pointed at a different enemy soldier.

Ideally you'd want each archer to have his own enemy to shoot at so no shots that would register as kills are wasted. Failing that, allocating the archers as evenly as possible works the best as you minimize the chances of a second kill rolled on a given enemy soldier that would be wasted as he is already killed by another archer firing at him.

So from that idea, we can determine for sure that having less width than the enemy means you are wasting shots by multiple-targeting the same interior enemies when you wouldn't have to. Also it's likely that using a wider line than your enemy is also disadvantageous, if in fact the extra width of archers multiple-target the end enemy units, or multiple-target any enemy units at all in fact. If they instead choose other as-yet untargeted units than that would prove even more effective than matching the enemy line's breadth... but I wouldn't bet on it, so it's likely that matching the enemy's width is most effective. I guess testing is needed, but as I'm at work right now I can't do it.

[Quillan]

I'm not really certain how individual targeting works. I'm not even certain individual targeting works at all. They might just target the center of the enemy unit and random scatter is determined by the computer.

However, deploying in deep blocks does have one drawback: the unit will only fire when everyone is in range, so they'll have to get closer to the enemy before they fire. This can result in you taking unanswered casualties. Personally, I tend to deploy my missile troops 4-6 ranks deep in most cases. They aren't so wide they become unwieldy and are still shallow enough not to make much of an impact on unit range.

[Kobal2fr]

This doesn't seem that bad, but if you analyze it empirically, you'll find that overloading end units with fire is a poor strategy. The right Y who gets shot at by 8 guys almost certainly dies, but possibly 3 or 4 times over, where those archers that scored hits could have killed 3 or 4 enemies if they were all pointed at a different enemy soldier.

Well, yes and no. It would certainly be true if archers did hit their targets consistently. But in reality, unless they are exped a lot, they have a very noticeable tendency to undershoot or overshoot. Now, the L and R archers undershooting will still miss, but if they overshoot, they have a longer line of "opportunity targets", if it makes any sense to you.

Sinan noted this in his thread relating to HA tactics : shooting the side of the box kills more than shooting the wide front, because overshooting arrows still fall down into the mass of men, instead of safely behind them. Same thing for L and R, I think.

Of course, this is speculating, I'd need to test thoroughly to be sure. But I'm no thorough tester .

[Satyr]

While I haven't say down and tested it, but from playing for a while, I would say that archers do not ONLY shoot things straight in front of the. If you have a long line of archers two deep and there is a square of spears in front of only the center 10 archers, all the archers will shoot at the square of spears and if there are no obstacles they will all hit with about the same level of accuracy. The point of this thread is that when they don't have line of sight you can improve their accuracy by putting them in a formation so that they all do have line of sight.

[Foz]

Of course, using archers in box formations instead of long lines impacts their results, because their fire will be much more concentrated and focused (ie a 4 wide archer unit firing on a 15 wide spear unit will only target the 4 men in the middle), so there is still a point in having wide archer formations.

I think I've mostly debunked this, or least determined it to have little effect in game terms. First things first though, the test outcomes.

I ran 10 trials of each setup, utilizing the following conditions:

- 15 minute time limit battle on Grassy Plain, Medium Difficulty
- British Retinue Longbowmen vs. HRE Armoured Seargeants, both set to attack

The thing I varied was, of course, the configuration of the Longbows (which I controlled). In each case I configured the longbows and then allowed the Armoured Seargeants to march at them, while the lonbows fired at will into the Seargeants (i.e. I did not order them to fire, for the sake of consistency. They don't move at all, and so remain more organized and consistent). When the archers turned tail to flee, I ended the battle and counted kills. The archers seemed to get off 7 or 8 volleys each engagement.

Retinue Longbows in Standard configuration (not repositioned from default):

Trial Kills

1 18
2 24
3 28
4 20
5 19
6 25
7 29
8 32
9 24
10 30

Total 249/760
Percent 33%

Retinue Longbows in 2-Row configuration

Trial Kills

1 31
2 19
3 25
4 32
5 34
6 22
7 30
8 25
9 32
10 28

Total 278/760
Percent 37%

Retinue Longbows in 4-Column configuration

Trial Kills

1 28
2 24
3 19
4 25
5 30
6 26
7 24
8 17
9 28
10 27

Total 248/760
Percent 0.33

The results, while not completely conclusive, suggest that the spread of your archers horizontally has little if any effect. They did slightly better in 2-row configuration, but there is no difference going from the 4-column which is very narrow to standard configuration which is considerably wider. If the horizontal spread was a major factor, I would assume that each step of further spread would improve kills, yet that clearly didn't happen, so it's likely some of the difference is due simply to randomness in the game engine.

One major reason for the very similar results in all conditions is probably linked to the following: I observed from watching the volleys that the archers, no matter the configuration, appear to aim for the center of the enemy unit. I conclude this because the vast majoriy of arrows fall inside a few ranks of center, no matter the formation, where they should be much more evenly distributed if each archer picks a target to fire at in the enemy unit. This would of course reflect the realities of missle warfare at the time - everyone aims for the center of the enemy so that even if they miss, they have likely hit someone in the group. Also you can see while you hold the shift key down with your unit highlighted, that no matter where you clicked the enemy line to attack, the red pole indicating your unit's focus is in the dead center of the enemy unit you clicked. This could just be a programming convenience, but as the arrows seem to fall predominantly all around that pole, I can't just write it off as coincidence.

I will admit that the 2-row archers did a bit better on the whole. Likely this is partly luck, and possibly a little due to a factor someone earlier mentioned: that the very outside archers have a bigger cross section of the enemy unit to hit, and so a few arrows that would be short or long from a more straight on shot are now hits for them. This effect increases the closer the other unit gets, until the outside archers finally have a shot along the longest diagonal (corner to corner) of the enemy unit and thus presumably best odds of making a kill.

____XXYXXXXXX Enemy Position 1
____XXXYXXXXX
____XXXXYXXXX
____XXXXXYXXX
____XXXXXXYXX

____YXXXXXXXX Enemy Position 2
____XXYXXXXXX
____XXXXYXXXX
____XXXXXXYXX
____XXXXXXXXY

AAAAAAAAAAAAAAAC Archer Lines
AAAAAAAAAAAAAAAA

Note how Archer C's shot diagonal (indicated by Ys) gets longer as the enemy approaches, allowing a much worse shot to still hit the huge mass of enemies in front of him. He can miss quite long or short and still he will almost certainly hit an enemy body as the enemy is several extra ranks thicker from his perspective.

So to wrap up the analysis, the 2-row format appeared a slight bit better, but it may be a fluke, and certainly 4% extra kills isn't enough to warrant lots of hard work to get your archers like that. To put that in perspective, 4% is 1 in 25, so the archers only managed to kill 1 extra man in every 25, a fact that easily could just be random. So if you find it simpler to put your archers into other formations to save space, The evidence seems to suggest the impact is minimal in their performance (save for possibly having them avoid obstacles with their fire, where I agree narrowing their line to shoot into breached walls and such is the best play).

[Kraxis]

This is certainly a letdown. In block formations the archers are less likely to get blocked by objects and are easier to move about. No need for wide formations it seems, while here are certainly advantages to blocks.

I remember well the rankpenalties in STW and MTW. They were great.
At least gunpowder and crossbow units are still affected.

[Kobal2fr]

Actually my original test was made using Militia Crossbows

EDIT : clarification - Xbows are indeed useless when arc-fired over another unit, but within own unit, Xbowmen are translucent, same as archers. Gunpowder just won't fire through/over troops, and the back rank only fires if/when the unit is in 2 ranks and cannot do a proper reload cycle.

[Von Nanega]

Random thought while reading this excellent thread. I believe the programming for each missile unit to fire on that particular sprites best target would probably be unwieldy, especially if there are lots of missile units in the battle map. Most folks don't have a Cray to run the calculation for this. So I believe CA / Sega did pretty good in general in setting up the fire. I will try some narrow formation in some upcoming battles against the heathens soon. I may even remember to post my results! Hard to remember though since I mostly read and post from work!

[Daveybaby]

A 4% advantage isnt statistically significant for the number of tests you did - it could just as easily have been 4% worse performance. It seems clear that there is no real difference - its just random variation.

Of course there is also the matter of what effect incoming fire will have on your archers depending on formation (due to the over/undershoot effect). It would be interesting to see how 2 sets of archers performed against each other with different rank depths.

Thats assuming, of course, that the over/under shoot we see on screen actually makes any difference to the number of hits - i.e. whether the game is actually tracking individual missile arcs to see if they hit anyone or (as is more likely the case, since this is how it works for melee combat) if the game works out a chance to hit for each missile based on all the relevant factors, then displays a precalculated number of hit/miss animations for each volley.