Is AC broken?

[Najo]

What prompted me to post this thread is a review of the ELH I read on this site, commenting how poorily the creatures in it were designed since their AC was lower than most characters and other creatures of similar levle/ CR's 'To Hit' bonuses - meaning that the only reason to ever roll to hit was to see if you either roll a 1 or a critical hit. This got me to peruse a number of the higher level monsters and gods through out the WOTC books, I also looked at the 2nd ed D&D monsters. What I found is most monsters in 3rd ed eventually have their Hit bonus supercede their own AC. This means that two dragons fighting of equal power and level automatically hit each other and cannot avoid an attack, which seems silly. 2nd ed monsters didn't do this and their AC remains above Hit bonus significantly. Keep in mind that AC is a DC, which means that it should roughly be about 10 points over the attack bonus for equal odds of missing or hitting. If my attack bonus is equal or greater than there isn't much (if any) chance involved. The modern d20 and SW address this problem by giving creatures a defense bonus which stacks with armor (meaning that their AC is higher on average the higher the level of play gets. Is D&D AC to low? Should characters be adding in a Defense bonus or some how be made harder to hit as their level increases. What are you thoughts on solutions to this and what am I missing that balances this out as the rules are now?

Nate

 

[Olgar Shiverstone]

A better question might be "When does D&D break down?"

In previous rules sets the rules started to come apart around level 9 or so. 3E is a bit more robust -- cracks seem to appear at about levels 12-13, but I haven't done enough high-level play to know where the system really breaks. Epic levels don't feel quite right, for reasons like you mentioned. I'd put the mark at about L18 with core rules, but that's just based on anecdotal evidence.

 

[shilsen]

I think Olgar is right.

Also, one thing to remember about the AC to Attack Bonus ratio is that as you go up in levels, PCs get iterative attacks, and what AC becomes crucial for is blocking multiple attacks. The first one may be certain to hit except on a 1, but it is unlikely that multiple attacks will hit.

While the above may not apply to many monsters (some of the more powerful dragons, for example, will hit each other automatically on every attack), their AC does not include magical enhancement or simple equipment, so it's not as lopsided as it may seem to be at first glance.

 

[WizarDru]

A better question might be "When does D&D break down?"

Well, I have a party of 6 18th-level characters, and I haven't seen it break down, yet. The game changes at higher levels, but that was expected, and the DMG makes that clear in several places. The ELH has whole sections to discuss the concept of how the game will and should change.

Even at epic levels, there are some things that the players can have trouble overcoming. I just discovered last week that 50 mph winds in a severe snowstorm can cripple a high-level party that isn't prepared for it (and this was with a high-level druid, who found he couldn't overpower someone else's Control Weather spell).

Now, if you're asking, does D&D lose a lot of verisimilitude at higher levels, I definitely agree with you. It's a game of high fantasy, and models that, even as it becomes more and more outlandish. I think Piratecat's Story Hour and the Rape of Morne Story Hour show that high-level play works fine...but it does require more and more out of the DM. Throwing orcs, even clever and classed orcs, no longer works right out of the box.

 

[Left-handed Hummingbird]

The problem isn't as much with AC as it is with the basic concept of the d20-system: The DC-mechanism. But the mechanism is still sound, IMHO, even though the d20 limits the range of randomness.

But regarding AC specifically, you might consider using the defense roll variant rule from the DMG. That would recreate some of the randomness lost with very high armor and attack bonusses.

 

[Vaxalon]

Another thing to consider is the effect of Expertise and Power Attack.

 

[isoChron]

In our campaign we decided to give an unnamed bonus to AC every time you get a new iterative attack.

At +6/+1 he gains +1 point AC-Bonus. Not much but better than nothing.
At +11/+6/+1 the AC-Bonus is +2.
At +16/+11+6/+1 the AC-Bonus is +4.

This should reflect the ability to parry/dodge blows/arrows/rays better with higher experience in fighting.
For simplicity we ruled that this bonus is always "on". Even caught flatfooted. Some may say it should be ruled like dodge ... *shrug*
In the end it raises the AC a bit but only for high level fighters it's really relevant. Mages will never get a fourth attack ...

Just a simple idea and it will work on monsters, too ....perhaps.

BYE

 

[Arnwyn]

I suppose AC is broken, but I blame it on the attack bonuses available to characters - they're too high. Previous editions kept them much lower, while in 3e the same Strength bonus that you get for damage also applies to your attack rolls! Meanwhile, AC is exactly the same from previous editions.

It was bogus when I first started playing 3e, and is still bogus now. (Like others have suggested, "hp" is the new AC now. That's not good, IMO.)

 

[Azure Trance]

Hm ... I know that at higher levels attack bonuses accrue faster then AC bonuses, but would it be a bad/unusual thing if it were houseruled to make it more even, consistently? Perhaps through a Base Defense Bonus or more defensive magic items? (for example)

 

[Numion]

The first attack is usually guaranteed to hit, but iterative attacks not. IMX D&D doesn't really break up, at least not until 20th level. My group wasn't intentionally trying to break it, though.

One spellcaster was broken at 18+ level, but he used Archmage PrC from FRCS. Not balanced, let's just say.

To your question: I don't think we should add a defence bonus. AC can be jacked up quite easily with available means anyway - but if you desire a low magic item campaign, then defence bonuses might be a good idea.