Entrenchments....what do they do?

[pgr]

Ok basic question, what do entrenchments do?

I know they help defenders and hurt attackers, but I am a bit curious as to the how? (I suppose this is a code question in a way).

Combat in the game is dominated by hit chance modifiers, so I'm assuming defenders receive bonus in hit % when firing. Are attackers penalized per level? Are hits somehow mitigated by entrenchments? (Absorbed if you will)

I guess that is the basic question, do entrenchments simply improve the combat efficiency of defenders, or do they actually offset combat damage received as well?

[Ace]

Up to level 4, they lower received damage by 0.9 exp(n) where n is the trench lvl. So, if I had trench lvl 3, damage received from each hit will be lowered to 0.9*0.9*0.9= 72%. As for trench lvls 5 to 8, they increase artillery damage, but I don't know by how much.

[Pocus]

Actually no, they lower to hit chance probability, but once a hit is done, they don't change it.

[pgr]

Actually no, they lower to hit chance probability, but once a hit is done, they don't change it.

Ah so they make the other fella miss...

I'm assuming this has an impact on shore bombardment resolutions? The higher the level of entrenchment level, the more likely the ships will miss the land batteries?

[Captain_Orso]

Taken from the AGEod WIKI: Combat Explained, this is exactly what it does: (1 - (target element's entrenchment-level[SUP]1)[/SUP] / 10)).
EG: An element is entrenched at level 4, when it is fired upon. Due to its entrenchment level its To-Hit probability is modified by (1 - (4 / 10)) == (1 - 0.4) == 0.6. If if the probability to hit the element without the entrenchment modifier is 25%, the with it, it is: 25 * 0,6 = 15%

[SUP]1)[/SUP] this term is my own, used for clarity.

Targeted elements will also take their protection value into account using the same formula. Normal Field Artillery however has "Protection = 0", but Coastal Artillery has "Protection = 5" and "Fort Batteries" have "Protection = 2".

[Ace]

And I thought I know the game

[minipol]

So a level 4 trench only lowers the to hit percentage from 25% to 15%? In other words, level 4 trenches only provide a 10 % bonus?
That isn't as big a bonus when you imagine a trench. Unless the troops are standing up, how are you going to get hit by bullets? Artillery yes, but bullets?
You will always get a few kills. Then again, if you look at the to hit chance in total, 15% isn't very high either so troops should have a good chance of not getting hit.
Having said that, I always felt the bigger levels of entrenchment > 5 weren't protecting the defenders enough.
It's very hard to even assault such a trench system. I had the Union attack my entrenched CSA troops at Manassas a few times, and the attacker only slightly suffered more casualties in almost
all of the attacks. That felt wrong if you're talking about level 7 trenches with a lot of heavy artillery.

[Captain_Orso]

And I thought I know the game

Awww, shucks, I just know how to find what to read, sometimes.

[Gray Fox]

From the same link, the artillery modifier was 1 + (level of entrenchment/10). So that would equate to a 10% bonus to artillery for each level of entrenchment.

[ArmChairGeneral]

minpol,
You have to compare normal (25%) to well entrenched hit chances (15%). If you think of it as them being able to deliver just over half as many hits (15/25 = 60%) as they would otherwise, entrenchments look pretty strong as-is. The raw reduction in hit % is only 10, which looks small, but you actually take 40% less hits than otherwise, which is a very large defensive advantage.

Fox,
So if you had entrench 5 then the enemy would be *.6 to hit and you would be *1.1 to hit for your artillery (only)? Or .5 for them and 1.1 for you?

[pgr]

Targeted elements will also take their protection value into account using the same formula. Normal Field Artillery however has "Protection = 0", but Coastal Artillery has "Protection = 5" and "Fort Batteries" have "Protection = 2".

Ah...so coastal Artillery has some real practical benefits when it comes to going after ships (say compared to field guns). I'm just trying to sort out how to protect my batteries from getting completely smashed every time a little fleet steams by...

[Captain_Orso]

Well, in general, if they are field pieces and you just want to protect them, I would say, don't put them in Bombardment mode

But if you really want to bombard with them, put them in a fort with an engineer and a supply unit. The engineer will insure they are entrenched as quickly as possible as deep as possible (even units inside forts entrench). A supply unit with supply gives them a combat bonus.

[Gray Fox]

PM = Protection Modifier: (1-level of enemies entrechment/10)*(1-terrain protection/10)*(1-unit protection/10)

Mathematically, the effect of entrenchment 5 would be 1 minus 5/10. However, for those who do not know, the highest entrenchment level for defense is 4. Levels 5-8 only affect entrenched artillery accuracy. So 5 would really equate to a PM of 1 - 4/10 or .6, and the "*.6" factor that ACG posted would be correct.

EM = Entrenchment Modifier (artillery only): 1+Level of entrenchment/10

Again, 1 + 5/10 would be the artillery bonus or 1.5. I believe in this case that a "1" equates to normal to hit chance and not +100%.

As a caveat, if no other factors were involved, the overall effect of entrenchment 5 would equate to a 40% reduction in enemy to hit chance and a 50% increase to the accuracy of your artillery only. That's how I read it.

P.S. the increase in artillery accuracy isn't done with magic. When a gun is moved to a new location, the science of putting a round on target was not well developed prior to the advent of computers. Even in Vietnam the theory was referred to as "charts and darts". In practice, a freshly sited gun was aimed at a target visually of a suspected distance and a round was fired. Then the crew adjusted fire so that the round actually landed near the target. In WW2, this usually involved firing one round over the target (long) and one under (short) which was nick-named bracketing, after which the gun would "fire for effect". In game, the longer that a crew operates a cannon from a fixed site (as a reflection of entrenchment level), the more accurately they should become at targeting locations within range. They would immediately fire for effect to the misery of the advancing troops.

[ArmChairGeneral]

It is unclear to me from the Wikis that bombardments use the same formula (and thus modifiers) as normal combat. That being said, anecdotal evidence supports the idea that Protection (at least) is taken into account in bombardment resolution since Coastal Artillery seem to take fewer hits than field artillery. Also, it makes sense that Protection matters to bombardment since why else would those guns need a Protection rating? Artillery rarely take hits in regular combat; if your Fort Batteries are getting hit in normal combat, you are already losing badly and the Protection value is almost irrelevant.

(Actually, now that I think about it maybe the Protection ratings are designed to guarantee that the emplaced guns survive normal combat so that they can be captured.)

[pgr]

Well, in general, if they are field pieces and you just want to protect them, I would say, don't put them in Bombardment mode

But if you really want to bombard with them, put them in a fort with an engineer and a supply unit. The engineer will insure they are entrenched as quickly as possible as deep as possible (even units inside forts entrench). A supply unit with supply gives them a combat bonus.

Hadn't thought about the supply unit . Frankly, I want to have something that will shoot at them Yankee gunboats...but I can't afford to build the coastal guns where I need them

[minipol]

minpol,
You have to compare normal (25%) to well entrenched hit chances (15%). If you think of it as them being able to deliver just over half as many hits (15/25 = 60%) as they would otherwise, entrenchments look pretty strong as-is. The raw reduction in hit % is only 10, which looks small, but you actually take 40% less hits than otherwise, which is a very large defensive advantage.

ACG, indeed compared to one another, the effect is 60% and as you say, that looks quite strong.
I didn't know about the artillery bonus. These 2 combined should produces good results.
One my parser for the battle log is done, it will be easier to see what happend when troops assault trenches.

[ohms_law]

I thought that I read somewhere that there's a built in preference for damage to be dealt to units with shorter range ("closer" units)? That ought to explain the lower amounts of damage that Coastal Artillery takes, pretty much all by itself.