How to Hit Things

'''Please Note: With update 14, Armor Class and a few other related mechanics have undergone significant changes. Until such a time as we have made a through adjustment to this page please refer to the 'Combat' section of the official release notes for a better understanding the current mechanic.'''

How to Hit Things
D&D Online is a complex game. Much of it involves attacking enemies and getting attacked by them, so understanding how the game decides whether an attack hits or misses is fundamental to good builds and tactics. This guide is an attempt to summarize the basic mechanics involved and many of the common but non-obvious factors that influence the chances of a successful sword swing or bow shot.

A Note on Stacking

Every bonus and penalty mentioned in this guide stacks.

The Basic Attack Roll
When you attack an enemy, or one attacks you, the game applies a formula using relevant attack bonuses and defensive values noted below to generate a raw percentage chance to hit. This percentage is rounded to the nearest 5 percent to create a d20 success chance. For PnP D&Ders it should be noted that the formula used by DDO is quite different from Tabletop D&D's THAC0 rules. In brief, a +/-1 variance in attack bonus or AC changes the chance to hit (before it is converted a d20 roll) by about 1%. Generally, to make a significant(5% increment) change in the actual "to hit roll" requires a +/-4 modifier. So a +5 Sword is about 5% more likely to hit than a +1 Sword. The article on Armor Class explains this formula in greater detail.

If your natural die roll is a 1, that attack misses, and if it's a 20, it hits. (A hit with a 20, and sometimes with lesser rolls, is sometimes a critical hit that causes extra damage, but that's a separate subject.)

Universal Modifiers
First, here are some rules that come more or less straight from pen-and-paper D&D, 3rd Edition and apply to all attacks.


 * You add your Strength modifier to your attack rolls with all melee weapons. You add your Dexterity modifier to your attack rolls with all ranged weapons. (This is just to hit things. Damage bonuses follow slightly more complicated rules. "Attack" is not a synonym for "Damage") A stat of 10 or 11 is "normal" and gives a modifier of 0. That goes up or down by +1 for every 2 stat points, so 12-13 gives +1, and 18-19 gives +4, and 8-9 gives -1, etc. Buffs like Bull's Strength and Cat's Grace can increase your chance of hitting, and debuffs like Ray of Enfeeblement can reduce it.


 * Another fundamental modifier is your Base Attack Bonus. Every character has a BAB that adds to all attacks and that increases automatically according to a steady, predictable pattern as the character gains levels. It doesn't rise equally fast for all classes, though.
 * Classes that are great at fighting (Barbarian, Fighter, Paladin, Ranger, and Monks using monk-specific weapons) get +1 BAB every level, including level 1.
 * Classes that are good at fighting (Bard, Cleric, Favored Soul, Rogue, and Monks using non-monk weapons) get +1 BAB only three out of every four levels.
 * Classes that are poor at fighting (Sorcerer and Wizard) get +1 BAB every second level.

Equipment & Proficiency Modifiers
Those modifiers above apply to everyone in all situations. Now let's look at ones that depend on your gear.


 * This one is tricky, but it's also very common, so it comes first: Two Weapon Fighting, known more generally as "dual-wielding" outside DDO. If you wield two full-sized one-handed weapons without the benefit of any Two Weapon Fighting feats, you suffer steep attack penalties of -6 to every attack made with your main hand and -10 to every attack made with your off-hand. These penalties are one of the two biggest reasons new players have difficulty hitting things. There are two ways to reduce these penalties, and even though these methods can be (and usually are) used together, the penalties almost never disappear completely.
 * If you have the Two Weapon Fighting feat, you effectively gain +2 to the main hand and +6 to the off-hand.
 * If your off-hand weapon is light, or you have the Oversized Two Weapon Fighting feat, (or both,) you effectively gain a +2 to each hand.
 * Notice that even if you have both these benefits — and you should if you're serious about dual-wielding — you still have a net -2 to both hands. Only Rangers who reach tier II or III of the Tempest Prestige Enhancement can reduce the penalty further.


 * There is a flat 20% bonus to a PC's attack (after the Attack Modifiers and Target's AC generate a percent chance to hit) if you are proficient with your weapon. This is roughly equivalent to a +16 to +20 modifier (or even more!) to your Attack Bonus. Wielding a weapon without proficiency would be very ill advised.


 * If you are not proficient with your armor, you suffer its Armor Check Penalty to your attack rolls. This might be anywhere from 0 to -7 depending on how heavy your armor is, whether it's magical, and whether you have any racial or class Enhancements that reduce ACPs.


 * Likewise, if you are not proficient with your shield, you suffer its Armor Check Penalty to your attack rolls. This is generally only -1 or -2, except for tower shields. Those have ACPs around -10. (Yes, "minus ten". That's not a typo.)


 * And while we're on the subject of tower shields: you suffer a -2 attack penalty just for holding one. This happens whether you're proficient or not (and remember, if you're not proficient, you take that penalty too).

Situational Modifiers
These modifiers can come into play depending on positioning, buffs, and status conditions that occur during the fight.


 * A melee attack against an enemy's rear 180° is called a "flanking attack" and is worth a +2 attack bonus.


 * Characters and enemies suffer -4 AC while knocked down, which essentially gives you +4 to hit them (or vice versa).


 * Attacks against a helpless target hit on any roll but a natural 1.


 * Sometimes, an enemy is visually obscured by magical effects. It may be buffed by a spell like Blur or Displacement or be inside the area of effect of a smokey, foggy spell like Obscuring Mist or Stinking Cloud. When your target is obscured, there is an extra chance that you'll automatically miss. This chance is a flat percentage based on what spell caused it, and it's checked before the normal attack roll. If you fail the obscuring check, the game doesn't even bother making a normal attack roll. You just miss. If you pass, you get an attack roll as normal. The True Seeing spell or item enhancement negates this special miss chance and gives you normal rolls on your attacks in these situations.


 * Some ghostly creatures are Incorporeal. You have a 50% chance to miss these outright and a 50% chance to get a normal attack roll, similar to how obscured enemies work. Using a weapon with the Ghost touch enhancement negates this special miss chance. True Seeing does not negate it.

DDO Specifics
Finally, there are some mechanics introduced by DDO that have no bearing on the original pen-and-paper rules.


 * There is a -4 attack roll penalty while moving. It does not apply to rotating in place but it does apply to jumping straight up and down. The Spring Attack feat negates this penalty. This penalty is the other big reason new players have difficulty hitting things in DDO.


 * Besides avoiding the -4 movement penalty, there is another benefit to standing still when you attack. If you continuously attack from one spot with no motion except rotation and jumps, you cycle through a sequence of two to four different attack animations depending on your Base Attack Bonus. What good is that? Well, if your cycle is three swings long, you get +5 to attack rolls every third swing, and if it's four swings long, you get +5 on the third swing and +10 on the fourth. While you're moving, your cycle never goes above two swings.


 * Cycles are two swings long if your BAB is 0. You pick up a third at BAB +1 and a fourth at BAB +3. For pure-class characters, this means:


 * Classes that are great at fighting (see the list above) get three swings at levels 1 & 2 and four swings at level 3+.
 * Classes that are good at fighting get two swings at level 1, three swings at levels 2-3, and four swings at level 4+.
 * Classes that are poor at fighting get two swings at level 1, three swings at levels 2-5, and four swings at level 6+.


 * Both melee and ranged attacks go through these bonus cycles, but only melee attacks have distinct animations for each swing in the cycle. Pausing your attacks resets the cycle to the first swing.


 * Ranged projectiles must physically collide with an enemy to get an attack roll against it. If the shot impacts terrain first, or if all enemies move out of the way before it gets to them, the shot won't get an attack roll against anything. Also, unless you have the Precise Shot feat, your projectiles attempt to strike the first enemy they collide with, which isn't necessarily the one you shot them at!


 * Client/server lag can make enemies appear at a different location on your screen than where the game's server thinks they really are. This can cause you to swing at enemies that appear to be right in front of you without even getting attack rolls, as those enemies have already hopped away from you, or perhaps were never there to begin with. You can anticipate this somewhat with practice.