Miss chance stacking

[Xintas]

I know that this has been hashed, rehashed, and return of the hashed, but I was not able to find an answer to this specific question. For multiple sources which grant different types of miss chances (e.g. Child of Shadow stance and the Deception Mantle power for an Ardent) would you make two separate rolls for those miss chances or would you use the better of the two?

Also, for maximum annoyance, if a character was in Child of Shadow stance, used an immediate to activate Deception Mantle, had concealment from some effect, and hit the target with the Obscuring Shadow Veil maneuver, how would that play out?

[Anxe]

First off, SRD says that concealment doesn't stack. Child of Shadow is a concealment bonus. Deception Mantle is not, so that does stack for two rolls. Obscuring Shadow Veil isn't concealment either. Concealment and Child of Shadow do not stack.

So your second example gets three miss chance rolls. Assuming your DM allows this.

[TuggyNE]

RC says miss chances never stack. I say that's hogwash, but it is written down, so it's something you'll have to either a) houserule away; b) ignore by not using the book; or c) do some crazy primary source RAW shenaniganry to say "neener neener RC doesn't count for anything".

I prefer a, since most of the time RC is actually rather useful as far as I can tell.

However, stacking the same type of miss chance with itself (i.e. two sources of concealment) obviously does not and should not work.

[Xintas]

So the takeaway here is:

Pre RC: 3 miss chances since they are different sources (except for the concealment and child of shadow)

Post RC: 1 miss chance because miss chances never stack, add, or happen concurrently

And the options are Ignore, houserule, or deal with it :smallcool:?

[Duke of Urrel]

So the takeaway here is:

Pre RC: 3 miss chances since they are different sources (except for the concealment and child of shadow)

Post RC: 1 miss chance because miss chances never stack, add, or happen concurrently

And the options are Ignore, houserule, or deal with it :smallcool:?

Yes, those are the options.

But I think the game designers have their reasons. A miss chance is a very powerful thing, more powerful than an Armor Class boost, because it requires re-rolling rather than makes a single roll less likely to succeed. Look at how the Blind-Fight feat works. It gives you a second chance to avoid missing a creature that you cannot see. Re-rolling a miss chance even once would (more or less, depending on the actual percentage) negate the effect of the Blind-Fight feat. Is this balanced?

POSTSCRIPT: Aha, I just thought of a solution. If we allow multiple miss chances, then the Blind-Fight feat should allow you to roll any failed miss chance a second time. That seems fair.

[OldTrees1]

Sidenote: If a concealment miss chance ever exceeds 50%, the PC just blinks during the attack to reduce the concealment miss chance back down to 50%.

[Duke of Urrel]

Sidenote: If a concealment miss chance ever exceeds 50%, the PC just blinks during the attack to reduce the concealment miss chance back down to 50%.

I think closing your eyes only affects your enemy's concealment – and does so by making that concealment total, which imposes a 50% miss chance. Whatever else we do, I think it's wrong to say that any kind of concealment may be "more than total" and impose a higher than 50% miss chance. So I would argue that closing your eyes can never make a creature less concealed to you.

One may argue (and has done so in this thread) that if concealment is combined with other factors, the miss chance may reasonably rise above 50%. For example, a 50% miss chance due to displacement (such as displacer beasts have) might be operative at the same time as a 20% miss chance due to dim light (such as the Darkness spell). If we allow multiple miss chances, maybe it's reasonable to require you to roll for two miss chances if a displacer beast lurks in the area of a Darkness spell. This is not, however, a 70% miss chance; this is the requirement to roll twice to determine whether you miss: once with a 50% miss chance and once with a 20% miss chance. If you closed your eyes in order to "improve" your chance to hit a displacer beast in this situation, you would increase the concealment miss chance from 20% to 50%. You would avoid the displacement miss chance, saving you the need to roll a second time to determine whether you miss. However, you would achieve this only by making the displacer beast effectively invisible. According to the RAW, you have a 50% miss chance when you attack an invisible creature only if you pinpoint the creature's location, for example by making a Listen check that scores 20 higher than you need, or by making a mêlée touch attack to find the creature by groping. If you fail to pinpoint the creature's location, the RAW give you no chance to hit the creature at all.

When I'm the DM, I'm not quite this strict. If you estimate, but do not pinpoint the location of an invisible creature (for example by means of a Listen check that succeeds, but fails to score 20 higher than you need), I indicate that the creature occupies a square area that is five feet longer on each side than the space that the creature really occupies. When you attack, you must aim into one of the five-foot squares in this area. If you aim into a space that the creature doesn't actually occupy, your attack has a 100% miss chance, but if you aim into a space that the creature does occupy, you have a 50% miss chance, as usual.