Attack rolls vs. Defense Rolls

[Aaron2]

I actually do defense rolls against a static attack DC from the enemy (11+attack modifiers). I used to do opposed rolls, but this is much easier.

I do the same but use 12+attack since this makes the two systems mathematically equal. I find that rolling as the DM really slows things down. I've generally got a bunch of stuff in my hands and have to fumble around to find dice.

Why 12+?: Let's take the simplest example. An attacker with +0 will hit a defender with an AC of 10 on a 10-20. That is 11 out of the possible 20 rolls or 11/20 or 55%. When we reverse the rolls, the defender now wins the ties, but he should still only succeed (i.e. make the attacker miss) 45% (100%-55%) of the time. 45% is 9/20 or 12-20. So, the defender needs a 12 or better to avoid being hit.


Aaron

 

[Garnfellow]

For our last two gaming sessions we've tried using the static 12 + monster modifiers for the defense roll, and the results have been pretty encouraging so far. We have a very large (typically 8-10 players) group, and this sped up the combats considerably, freeing me up to do more DMing.

We also are using magic checks from Unearthed Arcana.

 

[DrSpunj]

I'm doing the same thing (Defense Roll, DC 12+Monster's AB). I chose 12 for similar reasons. In the Core system the active player always wins ties (you have to equal or exceed the DC to beat it), and since the player's are now making the Defense rolls, they're the active players.

We're doing the same thing with Monster Saving Throws vs PC spell effects, though that hasn't come up nearly as often.

As a total side benefit I can yell out a pretty good number of attacks/DCs against multiple players simultaneously and they can all roll at the same time vs whatever DC numbers I gave them. I haven't timed it or anything, but I actually think things are faster this way since more rolls are being made in the same amount of time. Furthermore, they're getting to make more rolls so are more involved during "my" turns, and since I've unloaded a lot of what takes up my time on them I can put more effort into playing the baddies more effectively and missing fewer details (like forgetting the DR this badass is supposed to have so he sticks around for more than a single round! ).

OTOH, it's just plain fun to watch them come up with a natural 1 on their Defense rolls, since that equals a critical threat for the attacking monster. I've always rolled attacks and stuff out in the open, so there was always that tension there for the players when I rolled a 20 already. But somehow it seems infinitely more palpable when they're rolling and critically threatening/confirming the attacks against their own PC.

Thanks.

DrSpunj

 

[The Grackle]

Yeah. I've switched over to the defense roll and I love it. It's faster and easier on me to make the players do all the work.

One thing about it is that if you use action points to add to rolls, it gives even more power to the players, b/c they can use AP on their defense and offense. I don't mind it, b/c there's no DM fudging, so it provides a little bit of a safety net for them.

 

[Orm]

We only use opposed rolls for tumble checks. Works pretty well. It´s tumble check roll vs. attack roll. It prevent´s the rogue from only taking 15 ranks in tumble and feeling save to tumble around on the battlefield like crazy and adds some spice to combat.

 

[Aaron2]

Does anyone use the optional rule whereby players make a d20 roll for their defense rather than have a static AC score?

I made a spreadsheet to compare the % chance to hit with this method versus the normal one-roll method. I found that if your chance to hit is normally less than 30%, your chance increases (max difference is when you would otherwise only hit on a 20). If your normal chance is greater than 30%, your chance to hit decreases (max difference when you would only miss on a 1). From between 20% and 75% to-hit, the two system stay close (within 5% of each other).

As I was doing this I was thinking. On the defender's roll, does a 20 result in an automatic miss? Because of the variance, you might be able to ditch the 20-auto hits rule. This might reduce some of the incentive to do max Power Attack when the attack is extremely difficult.


Aaron

 

[ptolemy18]

Does anyone use the optional rule whereby players make a d20 roll for their defense rather than have a static AC score? How is that working out for you and your players?

I've never used it, but our DM tried to implement it once, and we players all voted against it.

It seems to me that it'd make combat (particularly high-level combat) sooooo slow... and I don't see what the advantage is, aside from throwing in an additional element of randomization.

For me, speed is important (we've played whole 4-hour sessions that were nothing but combats), and this rule essentially doubles the time it takes for combat, so I would avoid it. IMHO.

Jsson

 

[ptolemy18]

We only use opposed rolls for tumble checks. Works pretty well. It´s tumble check roll vs. attack roll. It prevent´s the rogue from only taking 15 ranks in tumble and feeling save to tumble around on the battlefield like crazy and adds some spice to combat.

Now this I recommend! It definitely helps "tumble" keep pace with higher-level play.

Jason

 

[ptolemy18]

I actually do defense rolls against a static attack DC from the enemy (11+attack modifiers).... It makes the players feel like they have some control over whether their character gets hit. It gives them something to do during the DM's turn. It makes my job a lot easier.

Whatever floats your boat... it's faster than having both attack & defense rolls, but it kinda destroys the illusion that the monsters & NPCs operate according to the same rules as the PCs...

Jason

 

[DevoutlyApathetic]

PC's and NPC's don't use the same rules already. NPC's don't gain experiance for one off hand example.

The math the above people are proposing comes out to identical chances. If somebody couldn't see who was doing the die rolling they wouldn't be able to distinguish the two methods.

The defense roll versus static DC stops the DM from having to roll 12 attacks against five different AC's and so on. It's a DM time saver.