Enlightened Grognard: One attack roll for area of effect

[amnuxoll]

One of my aims is to reduce the amount of dice rolling that a player does on their turn. A place where this comes up is making an area of effect attack (usually with a spell). One damage roll (as per 4e) is a good idea. I'd ideally like to make only one attack roll as well rather than a separate attack roll for each affected creature in the area. However, I'm leery about the "fun-ectomy" this is likely to cause. It would be a real bummer for your fireball to have no impact at all just because you rolled low. One pleasure of an AoE is knowing that you're likely to damage multiple critters.

So, what I'm looking for is ideas for how to keep the "some hit, some miss" aspect of an AoE attack but still only have one attack roll. I have an idea that I'm considering but I don't love it. Perhaps EnWorld community can come to my rescue? Does anyone have a clever but elegant idea on how this might be accomplished?

IMPORTANT: I do not want this thread to devolve into a discussion of whether this is a good idea or not. Thanks.

:AMN:

 

[Jurph]

The DM could declare targets as "kin" and group sets of them under a single roll. This is unlikely to help for burst 1, but at higher levels and bigger AoEs, it will save a lot of bookkeeping. If I were DMing I could see taking (for example) only one roll for all the minions affected. One roll for each solo/leader/controller in the fight is probably valid. If there are multiple skirmishers, brutes, or soldiers with identical defenses, rolling for them all together is probably kosher too. The DM can and should force a separate attack roll for each PC affected by a friendly attack... every table I've ever been at, some of the most delicious and cinematic tension is when a player decides to attack the bad guy despite the possibility of friendly fire.

There may be a way to give the attacker a bonus if he/she chooses to roll only once, but it's tricky to balance this out... the more creatures are in the burst, the more likely the player would be to hit some of them. If (Attack Bonus + 10.5) = median roll (MR), and the DM knows the median defense (MD) of the creatures in the burst, the DM could present a choice to the player:
(1) "Take ten" and get a guaranteed hit the weakest half of creatures in the burst, then roll an attack against one more target of the attacker's choice at a straight +2 (this keeps your lurkers and skirmishers from being immune to controllers).
(2) Roll a single attack for all creatures in the burst, with a bonus of (median roll - median defense +1), with the same expected outcome - just over half of the creatures hit - but the possibility of hitting all or none.
(3) Roll 2d20 and take the average, rounded down, for all creatures in the burst. Again, same expected outcome, but the possibility of hitting all or missing all. A crit on either roll should increase the damage, and two crits should do double damage, so the player doesn't feel like he "wasted" a crit.

Even with those choices, I think the DM should force separate rolls for PCs caught in the burst.

 

[jedavis]

Your kin solution reminds me of the mass combat system from Alderac's 3e Swashbuckling Adventures Campaign Setting. Effectively, you group every creature of the same type into a 'unit'. When making rolls with a unit, a result within +/-5 of the DC still results in some successes; hitting the DC exactly means 50% of the unit succeeded, with each point above the roll adding 10% to a max of 100% success and each point below results in 10% fewer successes, to a minimum of 0%. A similar system could be applied in this case to attacks against kin groups.

 

[amnuxoll]

My Solution

I've been thinking about this for a while and have come up with a solution that I like:

When using an attack that has an area of effect, roll three attacks (three d20s) simultaneously and sort them from highest to lowest. Apply the highest attack roll to one target of your choice. This is assumed to be the primary target of your attack. Discard the lowest attack roll and apply the remaining attack roll to all other targets (if any).


Things I Like About This:
1. It's fast. Roll three dice at the same time, all with the same modifier.
2. It's simple. You can explain it once and you don't need to look it up again.
3. The statistical "shape" is roughly the same as a single attack roll for each target though it is more "swingy" in the sense that you are more likely to hit a lot or miss a lot. All in all, a good compromise.
4. There are some obvious feats you can add to the game to let a PC focus on AoE attacks.
5. It allows you to give your best shot to the biggest bad guy (primary target).


Thoughts?

:AMN:

 

[slwoyach]

I would have a problem with that as a player. The fact that my fighter will never make a save that the rogue fails sucks.

 

[jefgorbach]

Consider that in most cases the area of effect (aoe) is caused a single event so only needs rolled once for targeting and once for the base damage inflicted on ALL targets within in aoe; adjusted for distance from ground-zero and target-specific damage resistance, cover, etc.
You could also presume all non-critical "extras" in the blast zone would react the same, with half making the median saving throw.

ie: you disrupt the approaching crowd by detonating a firebll in their midst, doing 3d6 fire damage to a 20ft radius centered on square#. The attack roll succeeds confirming it hit the desired square, doing 3d6 (12pts) fire damage to those caught in the blast and 6pts to the half who managed to reach cover/get out of the blast zone in time to avoid most of the damage.

Likewise, house-rule multiple sub-events (say a twinned fireball) are perfect duplicates bc of the spell, spacing, etc and simpy mulitply the base damage roll by the number of sub-events; ie: 12pts x2 fireballs for a base 24pts fire damage had the above fireball been twinned.