Large Creature and AoO

[Kenneth Souther]

Let me see if I got this correct. Examples are generic for the purpose of understanding.

A large Ogre, with a 10 ft. reach, gets an AoO on the approaching medium human. At the 10 ft. mark, the Ogre decides to do a CMB Trip for it's AoO. Ogre succeeds, human falls at 10 ft. mark. Normally, a Trip would provoke an AoO from the human, but since the human is still 10 ft. away, that would be impossible. Human will spend a move action getting up, provoking another AoO from the Ogre (possibly tripping them again, sundering, or just walloping them.)

If the Ogre's Trip had failed, human then would of been in range for a standard attack (after his move action), but would the human still get the AoO from the Ogre's failed Trip at the 10 ft. mark, even though they had to move another 5 ft. AFTER that event?

[Komoda]

Almost.

You cannot trip a prone target, so you cannot trip someone that is standing up. Otherwise your example is correct.

No. You can only take an AoO if you threaten at the exact instance.

[bodhranist]

The ogre can use a trip as it's AoO for the human moving towards it. In turn this provokes an AoO from the human being tripped, but since the human doesn't threaten the ogre, they can't do anything with that AoO.

When the human gets up, they provoke AoOs from anyone threatening them. However, unless the ogre has combat reflexes, it's already used its one AoO for the round, so that's not an issues. AoOs are resolved before the action that triggered the AoO, so tripping the human again doesn't do anything since they're still technically on the ground.

If the trip had failed, the human still wouldn't get an AoO. They get the swing when the trip attempt is made, which is made before they move, when they're still too far away to hit the ogre. Some DMs would rule that they'd get it anyway, saying that some part of the ogre had moved close enough for the human to hit, but the general consensus is that doing so is clearly a house rule, especially given that at one point (probably in D&D 3.5) there was a feat that allowed you to retaliate against opponents with reach, which reinforces the fact that without the feat you couldn't do things like that.