Damage Reduction

Damage Resistance (DR) is a measure of how much damage you (or a creatures) can soak up before losing hit points, after an opponent has landed a succesful blow. If you have a DR of 10 and get hit for 9 points of damage, you take no damage at all. If you have a DR of 10 and get hit for 15 points of damage, you only take 5 points of damage.

DR Forumula
The amount of DR you have id determined by the following forumula:

Shield BAB + Shield DR + Shield Mastery + (Material DR or Racial DR or Class DR) + Other

A quick explanation of those terms:


 * Shield BAB - Perhaps not the correct term. But, it is the DR you get ONLY when actively blocking with a shield instead of attacking.  And, it is based on your BAB.  The amount of DR you get for actively blocking with a shield is - (BAB/2)+2


 * Shield DR - You get DR based on the type of shield you are wielding. It is also modified by the magical bonus on the shield (so a +3 shield gives a +3 DR bonus)
 * Buckler or Light = 1
 * Heavy = 2
 * Tower = 4


 * Shield Mastery - There are various versions of the shield master feats and enhancements out there. And, all of these feats DO stack with each other.  The DR gained from each is as follows:
 * Shield Mastery - 3
 * Improved Shield Mastery - 3
 * Dwarven Shield Mastery - 2 / 4 / 6 (for levels I, II, and III of the enhancement)


 * Material / Racial / Class DR - These do NOT stack, you only get the best of whichever applies to you.
 * Adamantium
 * Shields - 1
 * Light Armor - 1
 * Medium Armor - 2
 * Heavy Armor - 3
 * Warforged DR
 * Barbarian Dr


 * Other - There may be some items / feats / skills / etc missed here. But those listed above should be all the common ones.

Example - A level 6 fighter with the regular and improved shield mastery feats, actively blocking with a +4 tower shield would have the following: ((6/2)+2) + (4+4) + (3+3) = 5+8+6 = 19 points of DR

Aspected DR
There is certain armors, feats, spells, and especially creatures that get DR, but only against certain types of attacks. A good example is skeletons which have a high DR against slashing attacks.

Monster DR
Currently, DDO is known to include monsters requiring adamantine (Iron Golems), bludgeon (skeletons and Clay Golems), and slashing (zombies) weapons to penetrate their damage reduction. DDO includes special weapons made from as adamantine, mithril, darkwood, cold iron, silver, and even "Byeshek", but only adamantine is known to be useful against monsters actually in the game.

Some monsters are vulnerable to magic weapons. Any weapon with at least a +1 magical enhancement bonus on attack and damage rolls overcomes the damage reduction of these monsters.

Whenever damage reduction completely negates the damage from an attack, it also negates most special effects that accompany the attack, such as injury type poison etc. Damage reduction does not negate touch attacks, energy damage dealt along with an attack, or energy drains.