Blackjackg
2013-10-15, 10:56 AM
This is a quick supplementary system for obsessive types and number crunchers who want it. I guarantee it will slow down combat, and most of the time it will add very little to your game, so obviously don't bother if it's not your cup of tea.
Using this system will tell you, when an opponent misses in combat, how they missed or where the blow fell. For example, did was it deflected with your shield, or glance off your natural armor, or did it miss completely?
There are many sources of AC bonuses, and the first step in this system is to divide up your bonuses into the following tiers:
Tier 1: Base Armor Class
Tier 2: Dexterity & Dodge
Tier 3: Shield & Defensive
Tier 4: Armor
Tier 5: Natural Armor
Like Armor Class itself, the tiers can be calculated generally in advance and recalculated based on situational modifiers.
Tier 1: Base Armor Class. This is your chance of being hit when standing perfectly still, well lit with a big target painted on your chest. This is equal to 5 plus or minus your size bonus. A small creature's Base Armor Class is 6; a colossal creature's Base is -3 (it literally is the broad side of a barn). Situational modifiers to Base Armor Class include the bonus for being behind cover, and the bonus against ranged attacks (but not the penalty against melee attacks) for being prone.
Tier 2: Dexterity and Dodge This is your armor class when you are aware of attacks and can try to move out of the way. It is equal to 5 plus or minus your Dex bonus, plus any named Dodge bonus.* The AC penalty against melee attacks from being prone comes under this category, as (for obvious reasons) does any effect that denies the subject its dodge bonus to AC.
Tier 3: Shield and Defensive This tier represents your ability to put something you're holding between yourself and the incoming weapon. Your named Shield bonus goes into this category, as does any bonus from fighting defensively. Weapons that grant an AC bonus, or feats that grant additional bonus from using particular shields or weapons also fall into this category.
Tier 4: Armor and Tier 5: Natural Armor I put these two together just because they're both really straightforward. Your Armor bonuses go into tier 4, and your Natural Armor bonuses go into tier 5. Simple as that.
This list probably doesn't cover all of the possible sources of AC bonuses and penalties, so DMs and players will have to use their own judgment. Most unnamed penalties to AC, such as those from spells, will go to Tier 1 or 2. I don't remember if there's such a thing as a Luck bonus (or Luck penalty) for AC, but if there is, it'll go into Tier 1.
* In case you noticed the asterisk on Tier 2: The only real change this system makes to standard D&D combat is that it hurts characters denied their Dex bonus to AC harder by taking 5 from the base and tacking it onto the Dex bonus. Personally, I like this because it keeps the tiers more distinct and it seems truer to the intent of the numbers, but it does change the way the game is played. If you want to stay accurate to the way it works now, calculate Tier 1 as (10 + Size) instead of (5 + Size) and Tier 2 as (Dex + Dodge) instead of (5 + Dex + Dodge).
So, for example, say a character is medium size, has a Dex bonus of +2 and a Dodge bonus of +1, carries no shield (0) but wears chainmail (+6). And just for kicks, let's give him a Natural AC of +1 (I don't know, maybe he's a Dragon Disciple). His AC is 20, and it gets divided up thus:
Tier 1: 5
Tier 2: 8
Tier 3: 0
Tier 4: 6
Tier 5: 1
To figure out where a blow lands, we then make a chart. I'll use the same Tier chart as above, but instead of having the raw numbers I'll create a cumulative total. If a tier (other than Tier 1) has a total of zero, just remove that tier. If a tier (other than Tier 1) has a total of less than zero, remove that tier and subtract the penalty from the tier above it (e.g., if Dex + Dodge = -2, remove Tier 2 entirely and subtract two from Tier 1). Here's the same character from before.
Tier 1: 5
Tier 2: 13
Tier 4: 19
Tier 5: 20
These numbers represent the attack rolls that mean a successful hit against you at each tier. For the sake of convenience, you may go one step further and convert your chart into a range, indicating what rolls mean unsuccessful hits at each tier.
Tier 1: <5
Tier 2: 5-12
Tier 4: 13-18
Tier 5: 19
You then compare the attacker's roll to the chart. A roll that falls into the miss range of Tier 1 was a wild shot that had no chance of hitting you even if you were standing still. A roll in the miss range of Tier 2 might have hit you, but you moved out of the way. On Tier 3, you deflected the blow with your shield or weapon. On Tier 4, the blow struck you, but your armor protected you from harm, and if the blow falls in the Tier 5 range, it got past your armor, but could not get through your tough hide. A blow that exceeds the Tier 5 miss range, of course, is a hit and damage is calculated as normal.
So what on earth could be the benefit of using such a complicated and unnecessary system? There isn't much; I mostly just made this up for fun. It could be useful in describing combats: it breaks the monotony of just saying "Hit" or "Miss" all the time and prevents embarrassing DM slip-ups like "The heavily armored iron golem skips nimbly away from your blow." The biggest benefit, as I see it, is that it helps adjudicate magical weapons, shields and armor that have an effect that activates when they are struck (e.g., the Shield of Wonder from the Goblins webcomic). You can simply know that the shield activates on a particular range of attack rolls.
As a supplemental rule for characters with an item like that, I would allow characters to take a -2 penalty to their attacks in order to specially try to block an incoming attack in a particular way. This allows them to allocate any amount of their Tier 2 bonuses (but not Tier 2 penalties, if they have no bonus) to Tier 3, effectively making opponents more likely to hit the desired shield or weapon. Characters with the Combat Expertise feat could use this option without taking the attack penalty.
Alternatively, a character with special magic armor could sacrifice any amount of their Tier 2 and Tier 3 bonuses in order to add half that number (rounded down) to their Tier 4, making the opponent more likely to strike their armor (but also more likely to pierce it).
Using this system will tell you, when an opponent misses in combat, how they missed or where the blow fell. For example, did was it deflected with your shield, or glance off your natural armor, or did it miss completely?
There are many sources of AC bonuses, and the first step in this system is to divide up your bonuses into the following tiers:
Tier 1: Base Armor Class
Tier 2: Dexterity & Dodge
Tier 3: Shield & Defensive
Tier 4: Armor
Tier 5: Natural Armor
Like Armor Class itself, the tiers can be calculated generally in advance and recalculated based on situational modifiers.
Tier 1: Base Armor Class. This is your chance of being hit when standing perfectly still, well lit with a big target painted on your chest. This is equal to 5 plus or minus your size bonus. A small creature's Base Armor Class is 6; a colossal creature's Base is -3 (it literally is the broad side of a barn). Situational modifiers to Base Armor Class include the bonus for being behind cover, and the bonus against ranged attacks (but not the penalty against melee attacks) for being prone.
Tier 2: Dexterity and Dodge This is your armor class when you are aware of attacks and can try to move out of the way. It is equal to 5 plus or minus your Dex bonus, plus any named Dodge bonus.* The AC penalty against melee attacks from being prone comes under this category, as (for obvious reasons) does any effect that denies the subject its dodge bonus to AC.
Tier 3: Shield and Defensive This tier represents your ability to put something you're holding between yourself and the incoming weapon. Your named Shield bonus goes into this category, as does any bonus from fighting defensively. Weapons that grant an AC bonus, or feats that grant additional bonus from using particular shields or weapons also fall into this category.
Tier 4: Armor and Tier 5: Natural Armor I put these two together just because they're both really straightforward. Your Armor bonuses go into tier 4, and your Natural Armor bonuses go into tier 5. Simple as that.
This list probably doesn't cover all of the possible sources of AC bonuses and penalties, so DMs and players will have to use their own judgment. Most unnamed penalties to AC, such as those from spells, will go to Tier 1 or 2. I don't remember if there's such a thing as a Luck bonus (or Luck penalty) for AC, but if there is, it'll go into Tier 1.
* In case you noticed the asterisk on Tier 2: The only real change this system makes to standard D&D combat is that it hurts characters denied their Dex bonus to AC harder by taking 5 from the base and tacking it onto the Dex bonus. Personally, I like this because it keeps the tiers more distinct and it seems truer to the intent of the numbers, but it does change the way the game is played. If you want to stay accurate to the way it works now, calculate Tier 1 as (10 + Size) instead of (5 + Size) and Tier 2 as (Dex + Dodge) instead of (5 + Dex + Dodge).
So, for example, say a character is medium size, has a Dex bonus of +2 and a Dodge bonus of +1, carries no shield (0) but wears chainmail (+6). And just for kicks, let's give him a Natural AC of +1 (I don't know, maybe he's a Dragon Disciple). His AC is 20, and it gets divided up thus:
Tier 1: 5
Tier 2: 8
Tier 3: 0
Tier 4: 6
Tier 5: 1
To figure out where a blow lands, we then make a chart. I'll use the same Tier chart as above, but instead of having the raw numbers I'll create a cumulative total. If a tier (other than Tier 1) has a total of zero, just remove that tier. If a tier (other than Tier 1) has a total of less than zero, remove that tier and subtract the penalty from the tier above it (e.g., if Dex + Dodge = -2, remove Tier 2 entirely and subtract two from Tier 1). Here's the same character from before.
Tier 1: 5
Tier 2: 13
Tier 4: 19
Tier 5: 20
These numbers represent the attack rolls that mean a successful hit against you at each tier. For the sake of convenience, you may go one step further and convert your chart into a range, indicating what rolls mean unsuccessful hits at each tier.
Tier 1: <5
Tier 2: 5-12
Tier 4: 13-18
Tier 5: 19
You then compare the attacker's roll to the chart. A roll that falls into the miss range of Tier 1 was a wild shot that had no chance of hitting you even if you were standing still. A roll in the miss range of Tier 2 might have hit you, but you moved out of the way. On Tier 3, you deflected the blow with your shield or weapon. On Tier 4, the blow struck you, but your armor protected you from harm, and if the blow falls in the Tier 5 range, it got past your armor, but could not get through your tough hide. A blow that exceeds the Tier 5 miss range, of course, is a hit and damage is calculated as normal.
So what on earth could be the benefit of using such a complicated and unnecessary system? There isn't much; I mostly just made this up for fun. It could be useful in describing combats: it breaks the monotony of just saying "Hit" or "Miss" all the time and prevents embarrassing DM slip-ups like "The heavily armored iron golem skips nimbly away from your blow." The biggest benefit, as I see it, is that it helps adjudicate magical weapons, shields and armor that have an effect that activates when they are struck (e.g., the Shield of Wonder from the Goblins webcomic). You can simply know that the shield activates on a particular range of attack rolls.
As a supplemental rule for characters with an item like that, I would allow characters to take a -2 penalty to their attacks in order to specially try to block an incoming attack in a particular way. This allows them to allocate any amount of their Tier 2 bonuses (but not Tier 2 penalties, if they have no bonus) to Tier 3, effectively making opponents more likely to hit the desired shield or weapon. Characters with the Combat Expertise feat could use this option without taking the attack penalty.
Alternatively, a character with special magic armor could sacrifice any amount of their Tier 2 and Tier 3 bonuses in order to add half that number (rounded down) to their Tier 4, making the opponent more likely to strike their armor (but also more likely to pierce it).