crawlSS_052_EVAC.txt: EV, AC and shield blocking Based on Crawl Stone Soup 0.5.2 Last change: 2009-11-18 by E. Grasland (use a fixed-width font like Courier to display the tables correctly) EV ~~ Effect ====== The EV reduces the chance to be hit by melee, ranged, spellcasting (beam) or trap attacks: an attack is successful if 1d(tohit) is greater than the EV of the victim. In a nutshell, for a monster's melee attack, (tohit) is approximately 18 + 1.5*HD, where HD is the number of hit dices of the monster. Calculation =========== Base evasion is 10, modified by several factors: * Character size The intrinsic size of your character (-1 for Ogre/Troll/Centaur/Naga, +1 for Halfling/Kobold, +2 for Spriggan) may modify your evasion depending on your race: +----------+------------+ |Race/form |EV modifier | +----------+------------+ |Default | 0 | |Ogre | -2 | |Troll | -2 | |Naga | -2 | |Centaur | -2 | |Halfling | +2 | |Kobold | +2 | |Spriggan | +4 | |Dragon | -8 | |Ice form | -2 | |Bat | +6 | |Spider | +6 | +----------+------------+ * Dodging skill Your Dodging skill increase your EV by (7 + (Dodging Skill)*Dex)/(20 - size), capped at (Dodging Skill)*(7 + size)/9 (see table below). Note that this bonus may be reduced if you wear heavy armour (see below). Here are a few sample base EV bonus, for reference: +--------+----++-----------------------++-----------------------++-----------------------++-----------------------+ | |Race|| Default ||Ogre/Troll/Centaur/Naga|| Halfling/Kobold || Spriggan | |Dodging +----++---+---+---+---+---+---++---+---+---+---+---+---++---+---+---+---+---+---++---+---+---+---+---+---+ |Skill |Dex || 8 |10 |12 |15 |18 |20 || 6 | 8 |10 |12 |15 |18 || 8 |10 |12 |15 |18 |20 ||10 |12 |15 |18 |20 |25 | +--------+----++---+---+---+---+---+---++---+---+---+---+---+---++---+---+---+---+---+---++---+---+---+---+---+---+ | 1 || 0 | 0 | 0 | 0 | 0 | 0 || 0 | 0 | 0 | 0 | 0 | 0 || 0 | 0 | 0 | 0 | 0 | 0 || 0 | 1 | 1 | 1 | 1 | 1 | | 2 || 1 | 1 | 1 | 1 | 1 | 1 || 0 | 1 | 1 | 1 | 1 | 1 || 1 | 1 | 1 | 1 | 1 | 1 || 1 | 1 | 2 | 2 | 2 | 2 | | 5 || 2 | 2 | 3 | 3 | 3 | 3 || 1 | 2 | 2 | 3 | 3 | 3 || 2 | 3 | 3 | 4 | 4 | 4 || 3 | 3 | 4 | 5 | 5 | 5 | | 8 || 3 | 4 | 5 | 6 | 6 | 6 || 2 | 3 | 4 | 4 | 5 | 5 || 3 | 4 | 5 | 6 | 7 | 7 || 4 | 5 | 7 | 8 | 8 | 8 | | 10 || 4 | 5 | 6 | 7 | 7 | 7 || 3 | 4 | 5 | 6 | 6 | 6 || 4 | 5 | 6 | 8 | 8 | 8 || 5 | 7 | 8 |10 |10 |10 | | 15 || 6 | 7 | 9 |11 |11 |11 || 4 | 6 | 7 | 8 |10 |10 || 6 | 8 | 9 |12 |13 |13 || 8 |10 |12 |15 |15 |15 | | 20 || 8 |10 |12 |15 |15 |15 || 6 | 7 | 9 |11 |13 |13 || 8 |10 |13 |16 |17 |17 ||11 |13 |17 |20 |20 |20 | | 27 ||11 |13 |16 |20 |21 |21 || 8 |10 |13 |15 |18 |18 ||11 |14 |17 |21 |24 |24 ||15 |18 |22 |27 |27 |27 | +--------+----++---+---+---+---+---+---++---+---+---+---+---+---++---+---+---+---+---+---++---+---+---+---+---+---+ This Dodge EV bonus is reduced is you're wearing a body Heavy Armour (an armour is considered heavy if your Armour skill is lower than 3 times the EV penalty of the armour; robe, animal skin, leather armour, troll hide and leather armour, steam and dragon hide and armour and elven armours of any kind are never heavy). If that's the case, the bonus is reduced by (15/Strength)*(2*EV_penalty-1) where EV_penalty is the EV penalty of the armour (the dodge bonus cannot become negative, though). * Body armour EV penalty In addition to the Dodge bonus reduction, most armours (heavy or not) will further decrease your EV by their EV penalty (see table in "Armour properties"). This penalty is reduced by your (Armour Skill)*Strength/60, up to half of the total penalty. * Other armours EV penalty Shields and bardings (Naga and Centaur) have EV penalties, which won't be reduced by your Armour skill. Shield's EV penalties are reduced by 1 for large species(Ogre and Troll). * Other modifiers The other EV modifiers are applied at the end: Forescry (EV +8) Stonemail (EV -2) Rings of evasion (variable) Randart evasion bonus (variable) Armour of ponderousness (EV -2) Repulsion field mutation (EV +1/+3/+5) Transformation into statue (EV -5) Merfolk into water (variable, lower if wearing heavy armour) Kenku flying (+20% EV, min +1, max +9) * Paralyzed characters Paralyzed character's base EV suffer a -8 penalty and all the modifiers described above do not apply, except the ones from Size and Repulsion Field mutation. Blocking ~~~~~~~~~ Effect ====== If an attack gets past your EV, there's still a chance to block the attack if the defender wears a Shield (Buckler, Shield, Large Shield) or is under the effect of a magical shield (Magic Shield from the Helm card in a deck, Condensation Shield from Ice magic or Divine Shield granted by The Shining One). If the attacker's pierce value is greated than the defender's blocking value, the attack does no damage. Calculation =========== The defender's blocking value depends on the nature of the shield: Buckler : 1d(Block) + 1/4*1d( Dex ) + 1/4*1d((Shield Skill)*2) - 4 Shield : 1d(Block) + 1/4*1d((Dex+Str)/2) + 1/4*1d((Shield Skill)*2) - 4 Large Shield : 1d(Block) + 1/4*1d((Dex+3*Str)/4) + 1/4*1d((Shield Skill)*2) - 4 Magical Shield: 1d(Block) + 1/4*1d((Int)/2) + 1/4*1d((Shield Skill)*2) - 4 N.B.: (Shield Skill)*2 is capped at (Shield Skill)+3. For a physical shield (Buckler, Shield and Large Shield), Block is the shield's blocking value, equal to the base shield bonus (3 for Buckler, 5 for Shield, 7 for Large Shield), increased by 5% per Shield Skill, by 13% for a dwarven shield (27% for a dwarf), by 7% for an elf wearing an elven shield and by 13% for an orc wearing an orcish shield (up to 30% for high-piety followers of Beogh). For magical shield, Block is equal to: 2 + (Evocation)/6 for a Magic Shield 2 + (Ice Magic)/6 for a Condensation Shield 3 + (Shield Skill)/5 for a Divine Shield Finally, this value is divided by 3 against an invisible opponent. For reference, a 15-Dex, 15-Str character wearing a Buckler has an average blocking value of: 0 with a Shield Skill of 0 2 with a Shield Skill of 8 3 with a Shield skill of 15 5 with a Shield skill of 27 With a Large Shield, it becomes: 2 with a Shield Skill of 0 5 with a Shield Skill of 8 8 with a Shield skill of 15 11 with a Shield skill of 27 The attacker's pierce value is equal to 1d(15 + tohit/2 + 5*past_blocks^2) - 1, where tohit is about 18 + 1,5*HD (HD is the number of hit dices) and past_blocks is the number of attacks already successfully blocked in the current turn. AC ~~ Effect ====== AC decreases the damage received when a melee, ranged, spellcasting (beam) or trap attack is successful. In a nutshell, the attack is reduced by 1d(AC) where AC is the AC of the victim. Calculation =========== For each piece of armour you wear (except shields), the base AC value is multiplied by several factors. * Armour skill factor Each level in Armour Skill increases the AC of an armour piece value by 7% (rounded down). * Racial factor Dwarven armours AC value is increased by 13% (27% for dwarves). Elven armours AC value is increased by 7% for elves only. Orcish armours AC value is increased by 13% for orcs only. Beogh followers modify the racial (orcish) factor depending on their piety (up to 2.25 times). * Deformed body mutation Characters with the Deformed Body mutation halve the AC value. Centaurs and Nagas have intrinsic Deformed Body. * Other Other sources of AC are added after the previous factors are applied: Rings of protection (variable) Weapon of protection (AC +5) Shield of protection (AC +3) Randart protection bonus (variable) Ozocubu's Armour (AC +4 +(Ice Magic)/3 ; not cumulative with heavy armour or other armour spells) Stoneskin (AC +2 +(Earth Magic)/5 ; not cumulative with other armour spells) Stonemail (AC +5 +(Earth Magic)/2 ; not cumulative with other armour spells) Necromutation (AC +3 +(Necromancy)/6) Draconian natural armour (AC +2 +1 at level 8 and every 4 levels after, every 2 levels for Grey Draconians) Naga natural armour (AC +1 at level 3 and every 3 levels after) Armour mutations (variable) Spider form (AC +2 +(Poison Magic)/6) Ice form (AC +5 +(Ice Magic+1)/4 ; Ozocubu's armour bonus becomes +1 +(Ice Magic)/4 ) Dragon form (AC +7 +(Fire Magic)/3) Statue form (AC +17 +(Earth Magic)/2 ; Stoneskin and Stonemail become AC +1 +(Earth Magic)/4)