Active blocking

Active Blocking
Player characters can actively block by holding the block key (default: left shift). While blocking, a character has increased Damage Reduction — especially if using a shield — and is immune to most special attack and weapon effects. This includes, but is not limited to, Scorpion/Spider Poison and Wraith Constitution Drain. Blocking even makes players immune to extra weapon damage and effects, such as Crippling, Flaming, Wounding, Maladroit, or Bane!

A blocking character cannot cast spells or attack with weapons. A character with the Shield Bash or Improved Shield Bash Feats can attack while blocking if he or she has a shield, using the shield's attack and damage values.

Characters cannot run normally while blocking. They either hop or somersault instead, depending on their Tumble skill.

Active DR Formula
Active DR is the additional Damage Reduction gained while blocking. It stacks with the character's Passive DR.

With Shield:

This formula applies when blocking with a shield against melee attacks. Active DR is halved if blocking ranged attacks.

Active DR = (BAB / 2) + 2 + Shield DR rating + Shield Mastery Feats + Shield Mastery Enhancements

The following feats and enhancements may further increase Active DR while using a shield. They all stack.
 * Shield mastery +3
 * Improved shield mastery +3
 * Dwarven shield mastery +1, 2, or 3 (for levels I, II, and III of the enhancement)

Two-Weapon Fighting:

This formula applies when blocking melee attacks while wielding two weapons. Active DR is divided by 4 if blocking ranged attacks.

Active DR = (BAB / 3) + 2 + Two-weapon Blocking Feat

The following feat may further increase Active DR while wielding two weapons.
 * Two-weapon blocking

Two-Handed Fighting, Single weapon & no shield, or Unarmed:

This formula applies when blocking any attacks while wielding a two-handed weapon, a single weapon but no shield or fighting unarmed.

Active DR = (BAB / 5) + 1

Examples

 * Example 1 - A level 8 fighter with the regular and Improved shield mastery feats, actively blocking with a +4 Heavy Adamantine Shield would have the following DR when using or blocking with shield:
 * Passive DR vs. melee and ranged = DR1/-
 * Active Blocking DR vs. melee = 1 + [(8/2) + 2 + 2 + 4 + 6] = DR19/-
 * Active Blocking DR vs. ranged = 1 + [(8/2) + 2 + 2 + 4 + 6]/2 = DR10/-


 * Example 2 - The same level 8 fighter with two weapons would have the following DR:
 * Passive DR vs. melee and ranged = none
 * Active Blocking DR vs. melee = [(8/3) + 2] = DR4/-
 * Active Blocking DR vs. ranged = [(8/3) + 2]/4 = DR1/-


 * Example 3 - A level 14 barbarian with innate DR5/-, a two-handed weapon (THF), and Stoneskin (DR10/Adamantine) would have the following DR:
 * Passive DR vs. melee and ranged = DR10/Adamantine OR DR5/-For normal attacks he effectively has DR10. For Adamantine attacks he has DR5/-.
 * Active Blocking DR vs. melee and ranged = [10 or 5] + [(14/5) + 1] = DR10/Adamantine OR DR5/- AND DR3/-For normal attacks he effectively has DR13. For Adamantine attacks he has DR8/-.