displacement

[True believer]

I am dming in a group and in a session the party's wizard cast a twin displacement and he argues that the misses chances stuck and that it has a 100% miss chance S:


I told him that it doesn't work like this but he argued the opposite. Was i wrong ???


Ty kind members :D

[ZamielVanWeber]

They don't stack. Displacement specifies that it works "as if the creature had total concealment" and then adds a bit about square targeting. Total concealment gives 50%. Mimicing it twice won't give you 100%.

Also IIRC, the Rules Compendium forbids stacking miss chances anyways, so it still doesn't work.

[Necroticplague]

I am dming in a group and in a session the party's wizard cast a twin displacement and he argues that the misses chances stuck and that it has a 100% miss chance S:


I told him that it doesn't work like this but he argued the opposite. Was i wrong ???


Ty kind members :D

No. The spells effect is 50% miss chance, not +50% miss chance. Also note that is says 'as if you had total concealment' appended to the 50% miss chance. And being totally concealed is a binary effect: you're either totally concealed, or you aren't. There isn't some 'ridiculously totally concealed' above that that gives 100%. Also, it's a spell effect, which by default overlap if you have redundant ones. Thus, absolutely everything within the rules says it's 50%.

[NecessaryWeevil]

Not only that, but two 50% chances do not equal a 100% in ordinary math anyway.

If you have two 50% chances to hit, and you have to roll a hit both times in order to succeed, then the probability tree looks like this:

Hit ------Hit
\-----Miss

Miss ----Hit
\---Miss

If you have to hit and then hit again, you have a 1 in 4 chance of succeeding. Which means a 75% chance to miss; 75% concealment.

[Grooke]

But again, its would only work like that IF they stacked, which they don't. If your player wants to increase his miss chance, he should go with Displacement + (Greater) Mirror Image (which isn't really miss chance but gets the same result vs most attacks). They are mechanically different and so those would stack.

[Psyren]

Also IIRC, the Rules Compendium forbids stacking miss chances anyways, so it still doesn't work.

Nitpick - RC forbids concealment stacking. However, Displacement is not actually concealment - it just flat gives 50% miss chance.

And if it were concealment, RC also has a clause about the GM being able to give more concealment than normal in certain situations.

I agree with your POV I just wanted to point out those two oft-overlooked things.

[NecessaryWeevil]

But again, its would only work like that IF they stacked, which they don't.

Yes, I know.