Mechanics of the Drill Promotion

[lymond]

I'd say of all the basic combat promotions, Drill is the one I understand least. Probably in part because I don't fully understand first strikes. (Most of the other promos seems pretty straight forward except for the whole medic/WM super healer line) From some things I've read and the fact that it's a protective trait bonus, it seems to be a more strictly defensive based promotion. I tend not to use the promotion line much myself even with protective leaders. So of a couple of questions for you experts:

1) Is drill strictly a defensive promo? Is there any affect on the unit from this promotion when that unit is attacking?

2) What are the mechanics for first strikes? Is it just to prevent collateral damage?

3) I see some folks throwing drill on a seige/cannon - like CR#/Drill 1. Why put drill on a cannon? Isn't CR/Barrage or Bombard more useful.

4) Is the promo helpful in stack defense or does it affect the specific unit only?

Thanks. Any general info on the underused (by me) promo would be great. I'm trying to determine the best use for it in stack and city defense and whether I should be making it more of a priority in balancing out promos within a stack of units or SoD.

 

[Rittmeyer]

I'll try to give a short answer (the whole truth is more complex then that, and someone will certainly point you to a more complete thread): combat happens in rounds. in each round, one unit can damage the other. rounds happen until one of the units is dead. what first strikes do is providing extra, special, rounds (first strike rounds), in which only the first strike unit can cause damage IF it wins the round. if it loses, no damage is caused to any of the units. try to picture Drill as an "Armor" promotion. It makes you "immune to damage" in a given number of rounds, before it wears out and normal rounds (in which your unit can be damaged) start.

giving drill promos to Siege will help the siege survive combat. it could eventually be the best choice, but I agree that CR is usually a better choice. also, Drill is way better if you can reach Drill III or IV, much worse if you are stuck on I or II. So, let's say you are Spain and you are the first to have Cannons. Being able to start with 3 promos, I would seriously consider giving my tech advantage Cannons the Drill line of promotions. This would mean I would need less of them to win a war, which would let me attack earlier, making better use of my tech advantage. Also, there would be few losses, and I would keep an excellent number of highly promoted Cannons to upgrade to Artillery and get into another war. It has to fit your strategy, your current situation, your playstyle.

So, no... it's not strictly defensive and yes, it helps when attacking. If it's better then Combat or CR, that's another story (and again, it's situational. There are no absolute answers, even though Combat fans may say that line is always superior).

About stack defense, it helps in the sense that your high drill units will not take much collateral damage, and they will be able to better defend the first waves of non-siege, since the non-drill units will be damaged. If you want to have a good experience with drill, a suggestion: play Ethiopia, when you get to gunpowder, swith to Theocracy/Vassalage, build 8-12 Oromo Warriors. They start with Drill I and II, give them III and IV with your promos from barracks+civic. Later, upgrade those to Rifle/Infantry (they will keep the Drills). Watch as the AI throws cannon after cannon on your stack, and them attack with a pile of cavarly just to be utterly destroyed while you take almost no losses.

 

[mfie]

1) It has the same advantage in attacking als in defending
2) A battle works in rounds (oyu don't see that), a battle alst about 4-6 rounds (with 70-130% strengt difference). first strike makes the unit immune to damage the first x rounds.
3) The cannon has more chance of surviving with drill
4) It only affacts the specific unit

EDIT: guy before me has a more detailled answer I see

 

[zyphyr]

1)No, drill isn't a 'defensive' promotion. It is of equal value to an attacker. It is just that many of the units that use Drill are primarily used for defensive purposes.

2)First Strikes are combat rounds that occur before the normal rounds. If the First Striking unit loses those rounds it takes no damage.

3)They are doing it for the 'no damage' attack chance.

4)It only applies to the specific unit, but it is as useful for stack defense as other promo that enhances the combat abilities of the unit.

 

[Groogaroo]

Regarding 1st Strikes, it's all pretty well explained here...

http://forums.civfanatics.com/showthread.php?t=308715&highlight=drill

 

[Navarre]

Not much to add, the Drill IV defender cornered it.

But being a fan of Zara Yaqob and Sitting Bull.... What do Drill promotions do ? They freaking ROCK!

Drill IV marines FTW!

 

[lymond]

Ha...thanks for alll the good info and thread. I've been playing CIV for a couple of years and never really paid much attention to drill or really combat mechanics in general. Pretty much just sit there and watch my guys die at 90% plus odds over 50% of the time. Drill looks like it could be useful epecially in certain situation or with the protective leader - I'm playing the new RPC so this is one reason I'm asking - just trying to get better.

Is there any other promos - let's avoid non-seige since i usually go CR anyway -that complement drill units most?

edit: Too bad HBO canceled "Rome". I could watch that for years. (or "Journeyman" if you like the actor)

 

[Tatran]

The name 'first strike' is misleading.
In other games I've played, like Magic the Gathering, a unit/card with first strike will
damage the opponent before the battle rounds start.
But, it would be overpowered in civ4 when units would have a lot of first strikes.

 

[Navarre]

Is there any other promos - let's avoid non-seige since i usually go CR anyway -that complement drill units most?

Well, Drill is good on attack when you have gunpowder units, so some stack defenders with Pinch and Formation are always good to have, especially for musketmen since knights are immune to first strikes. Riflemen can skip Formation most of the time, unless you face someone with heavily promoted cavalry. And of course, a Medic II or III.

 

[Ghpstage]

Not sure why people are saying Drill makes units survive more.

Comparing promoted Cannons against fortified Longbows with 60% culture defense and CG 1
Drill 4 65.2%
CR 2 73.4%

With culture defense blown to 0%
Drill 4 93.9%
CR 2 94.1

In this case CR greatly exceeds Drill for survival....
The only advantage Cannons get from Drill really, is that it works in field battles, there really is little point in giving Drill to siege units that aren't Machine Guns.


Getting the most of Drill requires you to consider what its actually good at, and having a little idea of the mechanics governing its performance.

First we have what first strikes actually do, that is they make the unit immune to damage in the first few rounds. One consequence of this is that they are significanty more likely to damage a unit that they attack.
The reduction in collateral keeps your Drill units strong making them useful stack defenders and very hard to move city defenders.


The 2 big mechanics based things that affect the value of Drill
The Ratio of after modifiers
Lets define this as the Drill units strength after modifiers (Combat promos, Shock, terrain, fortify etc) divided by the enemy units strength after modifiers
The way to get this R value, and much more related to combat mechanics can be found in this link

The higher this 'R' value is in favour of your unit, the more effective Drill will be in this fight. This is why Drill is very strong in defence, high defensive modifiers from cities, fortify and promos tend to give very high R values favouring the defender.
One result being that Drill is very good at a tech advantage, Drill Rifles are effective against Longbowmen defences.

The R value also has another significant impact, all experience calculations are done based on R values and not combat %. All promotions except Drill alter the R value.
As First Strikes push up the victory % without changing the R value you can expect to get more XP (and therefore more generals) with Drill.

The HP of the fighting units
The less HP a units has, the fewer rounds it take to kill it. Lower opponent HP often means the Drill unit will kill it without taking damage at all.

This gives Drill a very nice position as mop up after siege troops, this makes them great for attacking stacks when you intend to use collateral to mangle defenders, or an enemy stack before sending the troops in. The experience advantage can show up here quite often too.


What this means for Siege
The HP and R value attributes explain why Drill for Cannons sucked in the numbers I got for my earlier example, the HP of the defending units was full and the R value against the Cannons, quite high. As Siege is used to soften up hard targets the high HP will almost always be an issue, and as they always withdraw the XP advantage doesn't apply (1XP max for withdraw) and also, Siege units are immune to collateral from other Siege greatly reducing the extra bonuses value.


As for units that get a lot from Drill
Longbows, high defense bonuses make Drill in cities strong. Drill Longbows also make capable attackers following Siege units, in part because they are hard to budge after taking a city, and also due to the low HP defenders after collateral I mentioned earlier.
Muskets, Rifles, Infantry, Marines, Mech Inf all for the same reason really.

But....
Drill doesn't prove very effective against equal units in open field combat, Counter promos like Cover or Pinch prove superir in those cases, even Combat outshines Drill then, so remember to bring at least some counter promoted units with you.


On the Drill line itself, the Drill line gets stronger as you head down it, Drill 4 is very strong, but Drill 1 is almost certainly the weakest promotion there is.
If you can only get 1 promo, get Combat 1 not Drill 1, if you can get 2 but want a counter promo, get Combat 1 and the counter, not Drill 1.
After Drill 1, Drill starts to get reasonable (getting the rubbish Drill 1 out of the way is one thing thats very good about Protective!).

Some downsides of Drill

• Mounted units are mostly immune to First Strikes so your promotions may mean nothing
• No access to special promotions like March, Amphibious or Commando
• A bug exists that can make your Drill unit defend first depite a much better defender being in the same tile

 

[slobberinbear]

To add to Groo's link, I would highlight that drill is most useful when you have a chance of winning the "first strike combat rounds"; i.e., when your adjusted strength is close to the enemy's or higher. If it is significantly higher, then multiple drill promos give you a fair chance of winning and emerging unscathed.

This is why the Feudalism oracle gambit for protective leaders can give you some really outrageous offensive longbows, useful on offense or defense. Combined with Sitting Bull's archery bonuses from the Totem Pole and Vassalage, you can start with Drill III right out of the gate ...

 

[Rittmeyer]

With culture defense blown to 0%
Drill 4 93.9%
CR 2 94.1

In this case CR greatly exceeds Drill for survival....

I could be wrong, but I don't think Drill is counted for combat odds. Even if it is, I'm inclined to believe the math is not well displayed by the game. I get muuuch more wins on odds like 30% with a Drill III unit then with a non-drill unit with the same 30%. Always assume that it happens due to the extra combat rounds in which I cannot lose. Again, I may be wrong, and if I am wrong and your math is precise, then yes, it could be that drill is useless in making units survive more even against tech inferiority.

 

[pi-r8]

It seems like there's basically 2 situations where drill is good:

longbows in hill cities, because it helps them to defeat multiple attackers

Stuff that's paired with cannons or artillery, since it gives them a good chance of winning a battle without taking a scratch.

Otherwise combat is usually better.

 

[Udey1]

Do not forget one of the most useful aspects of drill. The ability to shrug off collateral damage.

 

[pi-r8]

Yeah that's true. Hard to plan for that in advance, though. I guess if you've scouted their army and notice a lot of seige units it might be good to promote more units to drill.

 

[Nares]

I could be wrong, but I don't think Drill is counted for combat odds.

It's only included in the Advanced Combat Odds mod.

I'll occasionally give drill I+II to a cannon to help with the best defender. The idea is that the cannon is screwed either way, but drill could help it do a little more damage to that best defender.

 

[Iranon]

Drill will not do much for your survival odds in fair fights. Things it helps more than most other promotions are chance of dealing significant damage despite (relevant in suicide units) and the chance of surviving the battle unscathed (relevant when much stronger or heavily fortified; especially the latter because it can mean that a single unit can hold off multiple attackers). It also helps against collateral damage.
The biggest advantage, however, is that Drill units excel against wounded opponents.

Unfortunately, the best defender code grossly overvalues first strikes meaning your Drill units will defend before they should... counter promotions (apart from Formation before Cavalry) will become less useful defensively.

 

[obsolete]

Watch as the AI throws cannon after cannon on your stack, and them attack with a pile of cavarly just to be utterly destroyed while you take almost no losses.

Drill units are pretty bad for defending against cavalry. Even all the way up to Drill IV, every FS will be ignored by the cav, and you only get 10% bonus vs them.

 

[TheMeInTeam]

Cavalry don't get inherent FS immunity obs. You yourself have noted thus in the past. Most other mounted does (excepting things like elephants, keshiks and cataphracts). Mounted without it need flanking II to get it.

 

[obsolete]

It doesn't matter. AI ALWAYS upgrades to stupid Flank. Believe me, it won't matter that their bonus isn't inherent. They always have 2 or 3 promotions to get at least Flank II.