Questions on the Aid Another action in combat

[Exocrat]

1. My PC has a whip and is adjacent to an ally who is engaged in melee with an enemy who has cover from my whip attack. If I use the Aid Another action to grant an attack or armor bonus to my ally, does the cover bonus apply to my Aid Another roll?

[Exocrat]

2. My PC has a whip and is adjacent to an ally who is engaged in melee with an enemy who has concealment. Does the concealment affect my roll for an Aid Another to grant my ally a bonus to attack or AC?

[Exocrat]

3. I am adjacent to an ally who is engaged in melee with an invisible creature who I cannot see. Can I use the Aid Another action to grant that ally a bonus to attack or AC?

[William Sinclair]

You are attacking against AC 10. There is nothing in "Aid Another" that says you can't aid someone in each of the above circumstances, as long as you can hit them in melee. It says that you are attempting to "distracting or interferring". While a whip doesn't normally inflict damage, it is "distracting or interferring".

I would rule that you would attack vs AC 10 with the appropriate modifer for each circumstance, and if your attack is successful, your Aid Another would work.

Understand for your last example, though, that unless you have Scent or Tremorsense or Blindsight or an insane Perception, you wouldn't be able to aid until you pinpoint them.

[Majuba]

All: You do not need to be adjacent to your ally, you merely need to be able to attack the square the enemy is in.

The specific language is very simple: "You make an attack roll against AC 10." It does seem exceedingly reasonable that this is, in some form, an attack roll against that opponent. Under that ruling (and a GM would be justified to say "Nope, just AC 10"):

1. Yes, add the cover bonus to the DC.
2. Yes, a 20% miss chance applies.*
3. Yes, a 50% miss chance applies.**

*: Things begin to get a bit hazy here, since you aren't actually trying to hit the opponent. However, if you can't quite see where they are, it makes sense that you might not quite help block their attack.

**: This would not be useable with the Bodyguard feat, as you cannot make Attacks of Opportunity against a foe with total concealment.

[Exocrat]

Majuba wrote:

All: You do not need to be adjacent to your ally, you merely need to be able to attack the square the enemy is in.

Right, thanks. I don't know where I got that idea from.

I agree with the interpretations above and would run things that way for house rules. But as written, I don't see how a cover bonus is materially different from a shield or armor or dodge or whatever bonus. You're trying to hit the imaginary concept of Armor Class 10, not a creature that might have defenses.

If for some reason cover applies to AC for Aid Another but other bonuses do not, then do other positional and environmental battlefield modifiers also apply to this roll? Higher ground, flanking, etc.?