I was preparing an encounter for the PCs with some barbarians of 5th level and I found myself wondering about improved uncanny dodge.
At 5th level and higher, a barbarian can no longer be flanked. This defense denies a rogue the ability to sneak attack the barbarian by flanking her, unless the attacker has at least four more rogue levels than the target has barbarian levels.
If a character already has uncanny dodge (see above) from another class, the levels from the classes that grant uncanny dodge stack to determine the minimum rogue level required to flank the character.
So, the party rogue/magus/arcane trickster (3/4/6) can sneak attack the ogres, but I guess he would not get the +2 bonus for flanking.. right ?
It's all or nothing : either Improved Uncanny Dodge prevents you from flanking and you get zero benefit, or you have enough levels in a class with sneak attack and you get all the benefits of flanking : +2 to attack and sneak attack to damage.
On rereading I have to agree, the last line seems to clear it up. I never considered it before but somehow I found myself wondering whether we played it right. Thanks ^^