It looks pretty good, although I didn't understand a couple things. What is DV?
Keep in mind the new Pathfinder Fighter class gets to increase Dex bonuses to armor with their Armor Training ability now. So they will have a somewhat better AC if they have a decent Dex.
You might want to look at the Unearthed Arcana book. It has several alternate rules for armor and calculating AC. If I remember correctly one of them is similar to what you have suggested here.
It looks pretty good, although I didn't understand a couple things. What is DV?
I think Micka refers to "Dés de Vie", which are Hit Dice in french.
This may be a flawed idea in the d20 system (including Pathfinder).
At higher levels when HD (DV) really make a difference in this new AC calculations, almost everything attacks more than once in a round. And almost everything that can do so has some attacks that have high bonuses to hit and some attacks that have lower bonuses to hit.
In the official rules, the good attacks almost always hit and the weaker attacks might hit, or they might not.
Also, high HD means high HP. These HP represent many things. When you lose HP, you might lose chunks of flesh, blood, or just sweat and energy as you work hard to turn deadly attacks into harmless ones. Therefore, creatures with lots of levels or HD have lots of HP, representing the fact tht it usually takes many hits to kill them.
These two systems, the multiple attacks in which the good attacks usually hit, and the high HP, balance out quite nicely. At low levels (and low HD) most enemies attack once and might miss often, but low HP means the occasional hit can quickly become deadly. At high levels (and high HD), most enemies attack several times and are likely to score multiple hits every round, but the higher HP means that it takes a lot of those hits before it becomes deadly.
In the end, it takes roughly the same number of rounds, at any level, to bring a healthy combatant down to zero HP.
Now, if you use your proposed rule to make AC go up as the levels (and HD) go up, then creatures and characters with some good attacks and some weak attacks will find their good attacks miss often and their weak attacks almost always miss. Everyone and everything will hit less often. But they will still have lots of HP.
Combats at higher levels will take longer and longer as the HD get higher and higher.
Combine this with spells. Many spells don't do HP damage. The ability to destroy an enemy instantly, say, with Disintegrate (or many other spells that kill instantly, or incapacitate instantly). These spells are balanced against the fact that you can assume it will only take a few rounds to chop the enemy into bits with swords and axes. Which to use? Spell or combat? The current system is fairly well balanced.
But, as combats take longer and loger because AC is getting higher and higher, characters may find that monsters that take a 3 or 4 rounds to kill in the official rules might take 8 or 10 rounds to kill with your new AC rules. But it still only takes one round to cast a good spell that wipes out the enemy instantly.
This kind of magic will become immensely more powerful.
Even the normal Evocation magic will become more powerful. If the fighters (and other melee classes) are missing a lot more often, but the lightning bolts and fireballs and cones of cold and chain lightnings, and all the other evocation spells, are sitll doing normal damage, then these spells are also much more deadly than using swords and axes.
Dragons with their breath weapons become extremely deadly for the same reason. Any moster with special magical attacks will become more deadly (because the mosnters with just claws and teeth will miss a lot more, making them weaker by comparison).
As you can see, the whole game system might get out of balance quickly.
I'm not saying the rule you propose cannot work. But I am saying that it will take a lot of careful thought and playtesting to balance it properly. It might also need some help by changing the way saving throws work, so spells and dragonfire and everything else will miss more often, just to keep up with claws and teeth and swords missing more often.
Ok If I have understand DM_Black, You say that the HP is here to simulate the combat expérience and the ability to reduce mortal blow by a "virtual dodge".
I'm agree, and I'm not agree whit you. Why ? For 2 things.
First : with initial system, only highest HP can win, because at the high level the attack hit everytime. So the character with a lot of HP win. I dislike the idea than there is only one the constitution to open the way of the victory. I have play with D&D 3.5 like that and I have see that.
Second : If you want to play an unarmored warrior, you cannot. Why ? Because with the initial system only the armor can do real AC bonus to resist at the monsters. With my system the armor stay better, but you can be unarmored. If you a good dexterity and good feat you can take the choose to don't wear armor, if you don't have affraid to lose your dexterity bonus...
the problem is, your system does not account for when things DO have alot of hit points. High HP is still better, its just a whole lot better when most secondary attacks are missing. Where as the lower HP characters/monsters are still threatened from that first primary attack that is more likely to hit.
Not to mention the d20 system assumes that either 1 you will not have full BAB (many classes do not) or the ones that do have full bab will be taking penalties to do something in addition to just hitting (power attack, rapid shot etc).
This is a big problem in systems like Wizards new Star Wars Saga Edition, where defences go up 1 every level. Power attack is useless as a penalty to hit is a big deal when attack and defence go up at the same speed. Characters without full BAB miss, ALOT. It tends to drag out combats, and mean that characters have to focus on getting their to hit bonus up instead of doing some of the more interesting or potent abilities that give you penalties to hit. The whole d20 attack system breaks down if you have scaling AC's.
In pathfinder, that level 20 character may not have alot higher AC(though magic gear is assumed to be given to characters concerned with AC as you level, so the level 20 character should have a significantly higher AC), but they can take alot more hits. Meaning they are harder to bring down unless facing a more powerful opponent.
I agree with you if my BBD increase by +1/Lv. But It is not.
It's +1 every BBA +3.
For a Fighter the best BBA
LV3 +1
LV6 +2
LV9 +3
LV12 +4
LV15 +5
LV18 +6This BBD don't impress a dragon Because a warrior without armor and dex bonus have AC 16. But the warrior is less ridiculous versus gogelin or little monsters. It's the same that a dexterity bonus so, it's an AC whenn the character have no armor. With a armor the AC calculate is the same, excepte maybe the warrior because the dexterity limitation bonus increase with the level. I think that Pathfinder créator have prevent if a warrior have a maximum in dexterity with a armor. So the effect is the same.
The only change with my rule is not when the character wear armor (maybe a little if the dexterity bonus is lower), but if he fight without.
If all attack hit easely, the winner is always the character with the most HP and the most Damage.
Don't need AC to dual in this condition. STR16 and CON18 is enought. My idea want to propose another option.
I understand that you are concerned with those not wearing armor or being stocked up on magic gear. The problem is, you still CAN have armor and magic gear, so with your flat +6 it will throw off the balance of attack penalties and hitting. For the most part characters are meant to wear armor, or their class has some feature (like spells or monks wisdom to AC) to boost them up if they dont wear armor. It you tack on an additional bonus, then AC's can get very very high, Imagine level 20 fighter in +5 fullplat,e a +5 shield, a 20 dex, +5 ring of protection, +5 amulet of natural armor, shield focus, greater shield focus and dodge. You are looking at an ac of 10+14(armor)+9(shield)+1(dodge)+5(deflection)+5(natural armor) then a +6 from your system. Thats an AC of 50 (and there are definately ways to get it higher).
At level 20 that same fighter with a Strength of 22 a +5 weapon weapon foculs and greater weapon focus, has an attack bonus of 38/33/28/23. The first attack only hits on a 12 or higher. the second attack needs a 17, after that is 20s only. And that is without things like power attack that reduce the changes of hitting. With power attack That first attack needs an 18 and all others need a 20. Melee and ranged combat characters would essentially be useless in that fight.
Mmm ... yes I see... But me DM, I never give all of the magic item what you have say. It's... so much !
- Shied +5
- Armor +5
- ect .. +5This is incredible. My player can have an objet +5 but... only one. Maybe a lot +1/+2 but that all.
But I understand what you say. I don't think this way because I play with low magic.
Low magic is a strange animal, and really it then becomes a judgement call. The game assumes players have a significant amount of wealth in magic items (see wealth by level chart). The items i mentioned dont even come close to matching the wealth of a level 20 character.
Also, in pathfinder especially the player does not need them to be available for purchase or commission or found in loot, the party mage will most likely make most of them. If you intend to give out/allow less then that, you are now fiddling with the power balance (not to say this is wrong, ofcourse i have played low magic games that were quite fun), but you disadvantage classes that rely on equipment. The fighter is still beholden to his gear, and the monk/caster less so.
But is hard then to comment on your changes without having a real idea of what kind of gear your characters will have at varios levels, since it clearly differs from the rules/guidelines as written.
Low magic is a strange animal, and really it then becomes a judgement call. The game assumes players have a significant amount of wealth in magic items (...)
(...) but you disadvantage classes that rely on equipment. The fighter is still beholden to his gear, and the monk/caster less so.
True, yet I understand micka's lament: the mechanics falls apart when you attempt to go with low(er) magic, which is one of the flaws of the system. His houserule attempt to rectify the very disadvantage that classes (like the fighter) must suffer in a lower magic setting.
As far as the OP's suggestion, the rules seems Ok with me.
However, like DM Blake said, creatures tend to have A LOT of DV/HD when the characters reach higher levels, which could lead to an escalation of BBD (soit dit en passant, bonus de base à la défence se traduitrait mieux par Base Defense Bonus, ou BDB). Be careful about dragons going from AC 45 to AC 65!
Another "danger" of the rule is to get into a situation where wearing armor is worst than running around naked. Armor should bring some sort of advantage, and the road to armor = DR is a very tricky one...
As DM Blake also said, many spell become comparatively more powerful than melee. While this usually sits well in a low magic setting (magic is rarer but more powerful), it has to be a conscious consequence and your players should be well aware of that.
'findel
But I understand what you say. I don't think this way because I play with low magic.
And there is the source of the reason you're looking to change the system. You need to compensate for the fact that you've already removed a bunch of rules.
There are some easy "non-magic" ways to do this. For instance, allow that armor and shields can be "improved". While a normal suit of full plate grants a +9 armor bonus to AC, you could simply let your players purchase that same suit in an improved version that grants a +10 armor bonus to AC. Make the cost of such improvements equal to the costs shown to make magical enhancements. No more magic, no more balance problem.
On the other hand, it's also assumed that players have access to things like a ring of protection which offers bonus to AC other than a simple armor bonus. In those cases, your best bet is to change the "fluff" description and allow that the players purchase other non-magical AC improving items like helmets. Just change the description so it's not magic that's providing the bonus.
Finally, low-magic creates yet another difficulty: saving throws. Just as players without access to magic items will have problematically low AC, so too they will have problematically low saving throw modifiers. Without things like a cloak of resistance your players will always be behind the designed scale. Poisons, catching on fire, disease, curses, werewolf bites... all kinds of things that aren't magic will still have numbers your players may not be able to meet.
You have more work to do than just giving a bonus to AC.
(...)You have more work to do than just giving a bonus to AC.
But if Micka fully assumes his low magic setting, there will be less need for saving trows and those will become more significant. Diseases and poisons become frightening again. Traps are more than speed bumps. A sorcerer will admittedly become a bigger threat than it would have been in 3.5 or Pathfinder core "level of magic". A dragon will not be a dragon, it will become THE dragon. Being "behind the design scale" is, as crazy as it sounds, part of the "charm" of a low magic setting.
Assumed thoroughly, the low magic setting works, but it needs fine-tuning. One of the first pit-stop is usually about AC vs BAB...
'findel
If I want a game with a lot of pyrotechnique magic I play D&D4.Soit dit en passant merci Laurefindel ;)
actually from what i've seen 4E has alot less in ways of stat boosting and AC boosting items. Things are kept much closter to the roll 10 or better to succeed ratio (at the expense of variety).
Honestly you might want to just consider the player 1 or 2 levels lower when designing the encounters. It might be easier then re-tooling the AC system, and would mean even lower AC characters aren't always getting hit. After all since magic gear is assumed when considering monster CR you probably should be throwing lower cr encounters at them anyway.