
Sir Cowdog |

Cornugon Smash: When you damage an opponent with a Power Attack, you may make an immediate Intimidate check as a free action to attempt to demoralize your opponent.
Hurtful: When you successfully demoralize an opponent within your melee reach with an Intimidate check, you can make a single melee attack against that creature as a swift action.
Felling Smash: If you use the attack action to make a single melee attack at your highest base attack bonus while using Power Attack and you hit an opponent, you can spend a swift action to attempt a trip combat maneuver against that opponent.
The reason I find this a little confusing is because Cornugon Smash and Hurtful are very open ended effects. All you need to do is to damage an opponent with Power Attack. While Felling Smash is just a little more specific in that it refers to an 'attack action' at your highest BaB while Power Attack is on.
My question is this: Can you wait until after you hit before choosing to go with either Felling Smash or the Cornugon Smash + Hurtful combo, as long as the hit in question is done at the highest BaB? Or do you have to declare that you're using Felling Smash before the attack?

TGMaxMaxer |
Yes, you can choose which feat you want to use as a swift action, after finding out if you hit on the first swing.
(provided you move no more than a 5ft step, or not at all)
Step 1: You make a single attack at your highest BAB, with the power attack penalty.
1A: You hit. You then get the Free action Intimidate Check. (do this first, since you get it as a free action).
1Aa: You succeed on demoralize, now you can choose to trip (Felling Smash) or another attack (Hurtful) as a swift action. If you choose to trip, your attack ends, you still have a move action left. If you choose to make a Hurtful attack, you may either move, or continue your full attack if you have BAB 6+, or TWF+, as it does not specify the attack action, just any power attack.
1Ab: You fail to Demoralize, you may -Still- take the Felling Smash swift action trip attempt, or if you have more attacks from BAB or TWF etc, you may choose to take a full attack and hope those hit, you succeed on another attempt to demoralize (with a +5 DC for a failed attempt already) and trigger your Hurtful attack that way.
1B: You miss, you may make any other attacks you have from BAB or TWF, Felling Smash is locked out as a choice (since it specifies a Attack Action which gives only one swing), but if you hit on any following attacks you still get to Demoralize, and if successful, take the Hurtful swift attack.

TGMaxMaxer |
I have a Lore Warden 5/Skulking Slayer-Scout 6 (pre-unchaind).
I didn't have access to Hurtful (2 year old PFS character) but I took Felling Smash, Gr Trip, and Gr Dirty Trick. They end up damaged, prone, and blind at the end of my turn, with a Standard and Move required to get up and become unblind.
I barely had room for the feats in there, but Cornugon Smash and Hurtful would have made the build monstrously worse... I might even spend the 10 prestige to retrain them if I ever get the chance to play him at 12+.
As a matter of fact, with the Intimidate Skill Unlock for the rogue, I think I will end up at least taking Cornugon Smash the next time I play him.

TGMaxMaxer |
Why would it do that? You get the Demoralize free with any power attack. No other restrictions, just a power attack that hits. If it happens to be your first attack, then you can trigger Felling Smash afterwards, and have a damaged, prone, demoralized enemy.
There is no order of Standard Swift and Free that says you have to choose one before the other, free and swift actions can be taken between attacks in a full attack, even if the free action is a 5ft step to bring a new target into range.

Sir Cowdog |

I'm not entirely certain that hitting is processed before rolling damage. Reading the combat section of the rules, it says:
An attack roll represents your attempt to strike your opponent on your turn in a round. When you make an attack roll, you roll a d20 and add your attack bonus. (Other modifiers may also apply to this roll.) If your result equals or beats the target's Armor Class, you hit and deal damage.
It seems to me that hitting and dealing damage happen at the same time, not one after another. While it's common to roll to hit first, then roll damage, the wording seems to say that the actual act of hitting and damaging happen at the same time.
I suppose there could be situations involving damage reduction where you can hit, but not damage, a target. That would certainly invalidate the intimidate check from Cornugon Smash. But it raises an interesting question about the trip attempt from Felling Smash due to the wording of only requiring a hit. Damage Reduction says if you don't deal damage, you don't get most effects either. But Tripping doesn't normally do damage anyway, so I'm not certain.
Whenever damage reduction completely negates the damage from an attack, it also negates most special effects that accompany the attack...
On a related note: I've rolled my hit and damage dice all at once since 2nd edition. Different colored dice to denote which is which, and roll them all with a single toss. Saves time in games with lots of players.

Mucronis |
There is some "evidence" to support Casual Viking's point. Look at Combat Maneuvers.
Combat Maneuvers.
FAQ regarding trip and vicious stomp.
"Combat maneuvers are attack rolls, so you must roll for concealment"....
As Combat maneuvers are attack rolls, the trip + vicious stomp FAQ shows that there is a difference between hitting and doing damage/causing an effect (trip/disarm and so on)
Now Combat maneuvers and normal attacks are NOT the same, they are however closely resembling each other, so making the call that they behave in equal ways seems logical, Pathfinder is a game where for various reasons there is a systematic progression to things (you hit, then do damage)
then again, some of the more experienced rules guys can probably prove me wrong (I have made mistakes, as we all do from time to time)

Sir Cowdog |

As far as I can tell from reading what you linked, there still appears to be a difference between making the rolls and the actual effect caused by those rolls. If you're treating a combat maneuver just like an attack then it goes back to what I quoted earlier in bold about attacks; with the only difference being that instead of the result of (Hit+Damage), you get (Hit+Condition). They still happen at the same time.
But I agree that it would be nice to hear more different points of view. Either way it's a very interesting nuance of the rules.