Saucey, this guide should be updated a bit.
The formulas for successful hit/dodge are not very complicated, but it's somewhat different than we used to think.
First, there is a number X used in calcualtions, and it's X=2/5=0.4
Instead of writing 0.4, I'll use X in the formulas.
Second, anyone who joins fort fight, even if he has no points distributed in skills/abilities, gets +25 to hit chance and +10 to dodge chance by default. That's why you can go into fort fights as a pure swimmer and still kill something.
All set? Ok, the base formulas (without soldier leadership bonus and sector bunuses):
Chance to hit=25+aim^X+leadership^X+stamina^X
Chance to dodge=10+dodging^X+leadership^X+hiding^X
Let's say we have nonsoldier defender who is standing on the ground inside the fort alone with this stats:
Lead 135
Dodge 16
Hiding 96
Obviously, that player according to the formula above have (I'm rounding the root):
Chance to dodge=10+16^0.4+135^0.4+96^0.4=10+3.03+7.11+6.21=26.35
What happens when a player is on a sector? That's also easy. Values from all sectors are displayed before a fight starts. So a tower level 3 in a small fort always adds 24 to chance to hit and 18 to chance to dodge.
So if our player from example is a dueler and is standing alone on a tower level 3 that is not dueler's tower, he gets:
Chance to dodge=base chance to dodge + 18= 26.35+19 = 44.35
But what happens if our dueler goes for dueler's tower level 3? That tower will grant him +15 class bonus on both chance to hit and chance to dodge, because it's his own tower, so in that case we'll have:
Chance to dodge=Base chance + 19 + 15 = 59.35
For more examples with pics, but without formula, you can check this post:
http://forum.the-west.net/showthread.php?p=519738#post519738
As this is only the basics, I'm not covering worker sector bonus, but if you're a worker, your class gets even more on chance to hit and chance to dodge while standing on the building, tower or wall (30%, or 60 if class premium activated). However this 30/60% sector bonus doesn't apply on worker's class bonus if they're standing on the worker's tower. So a worker on worker's tower would get tower's bonus with 30% (or 60%) applied, and after that the worker only bonus would add to that.
Also I'm not covering soldier leadership bonus because of a fact that you'll be moving all over the place and you can't know how many points you'll get from a nearby soldier and if you'll get any point at all - there are too much of pure HP soldiers with 0 leadership lately in fort fights.
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A few last notes:
1. As we had before in help/wiki, that you get +9 if your skill is 210... That is not correct any more. Now you get +8.50 if a skill is 210. You'd get +9 if your skill is 243.
2. We know that for any number N, 0^N=0, and 1^N=1. This means you should have at least 1 in all fort relevant skills. While attacking, a pure swimmer would get as a chance to hit 25+0+0+0=25. But "not that pure" swimmer would certainly have at least 1 (from SP, AP or equipment) in aim, leadership, hiding and stamina, so his chance to hit would be at least 25+1+1+1=28.
3. Noone knows and noone ever tested if luck bonus from holiday set applies to dodge/hit luck in fort fights.
4. Since the bonuses gained from skills drop rapidly as higer the skill goes (which is normal for any mathematical root), you get less chance (to hit or to dodge) if you put every AP/SP into one thing and neglect other fort relevant skills. Example? If you have 243 SP and put all 243 into aim, you get only +9 to hit chance. But if you distribute those 243 points equally into aim, leadership and stamina, that will be 81 into each of those three skills, while attacking you get +5.80+5.80+5.80=17.4!