Need Help with Invisibility Rulings

[LokiDR]

Yeah, I've got a lot of those.

Yeah, I noticed. You keep showing up in same threads I do

I could possibly go with the idea of allowing AoO when you cannot see the attacker, if there was some reference point for the DC to detect that you have an opportunity to MAKE your AoO. Listen seems the obvious choice to use... of course then we're stuck in a bind AGAIN if the person in question has both deafness AND blindness cast on them.

Well, there is such a thing as completely screwed.

Here's a chart off the top of my head. Keep in mind, this is a check for determining whether or not you detect the chance to make an AoO... not the same as identifying the square you need to strike at.

DC 15 - Detect someone is leaving a square you threaten
DC 10 - Detect someone casting a spell with verbal components
DC 20 - Detect someone casting a spell without verbal components
DC 25 - Detect someone using a potion
DC 15 - Detect someone sheathing a weapon
DC 20 - Detect someone making a ranged attack

Thoughts?

It is a DC of 20+base target to pinpoint a person by sound. In combat, there is normally lots of clanging, hence circumstance penalties. I would say 20 for casting a spell, going up from there. You have have to be really good or really lucky to find people by sound. Hey, I never said people had to have a GOOD chance.

 

[Norfleet]

Well, here's something for you: Let's say we have an invisible opponent, perhaps wearing a belt of potions. He walks quietly by you. You might hear him, and if you subscribe to the AoOs against invisible opponents camp, you can take an AoO against him.

Now what happens if he TUMBLES past you, making no attempt to be quiet, thereby rattling his potion bottles noisily, and makes a successful tumble check? Of course, he's invisible: You have no way of knowing that he tumbled. Do you still get an AoO now?

What if he tumbles through, making the same noise, but failing his tumble check? Do you get an AoO now? How can you, who can only hear the noise, really tell the difference?

 

[LokiDR]

Hyp would say, pick a square, use up the AoO, and have no chance of hitting if he made his tumble check.

I would say, pinpoint the person (listen DC ~25) and then swing. I the target of the AoO has successfully tumbled, you don't have a chance to hit, and just blew you AoO. You could also hit your own wizard though, so this risky one way or another.

 

[Hypersmurf]

Hyp would say, pick a square, use up the AoO, and have no chance of hitting if he made his tumble check.

Not quite. I would say if he made his tumble check, you don't use up the AoO. If the character wants to swing his sword in the direction of the noise outside of his normal action, that's cinematically okay, but mechanically futile.

He didn't provoke an AoO, so you can't actually expend your chance to convert a cinematic swing into an attack roll.

If he fails his tumble check, then you have the chance to use (or waste) your AoO attempt.

-Hyp.

 

[Elder-Basilisk]

The difficulty with either of these is that, if someone is in melee combat with the character, they don't need to actually see what is happening in order for their chances to suddenly enjoy a better chance of hitting.

Either sheathing a weapon or making a ranged attack preclude significant amounts of dodging or defense oriented activities which would enable the character to avoid the sword being blindly slashed in his general direction. Thus, I think that either of these should provoke AoOs if done within the threatened range of an opponent who would have any idea that the character is there (attacked previously from direction, blindfight, attempted to attack the character in the previous round, etc).

DC 15 - Detect someone sheathing a weapon
DC 20 - Detect someone making a ranged attack

Thoughts?

 

[Tar-Edhel]

What if he tumbles through, making the same noise, but failing his tumble check? Do you get an AoO now? How can you, who can only hear the noise, really tell the difference?

As mentionned by Murrdox, that's exactly why I prefer no AoOs on invisible opponents. Much simpler and frankly not the game-breaker LokiDr anticipates

There are plenty of ways to negate invisibility anyway, most of them available at low level.

 

[SnowDog]

My decision (so far)

Well, after reading everything here (and in other places) I think I've come to some decisions. I know this is dangerously close to House Rules but I figured I'd post here for closure.

Invisibility + AoO (interpretation)
In our campaign, Attacks of Opportunity reflect a conscious choice on the part of a combatant to take advantage of a perceived opening in a defense.

As such, you do not provoke attacks of opportunity while invisible. Even though your presence and possibly location may be determined by your attacker, she is not completely aware that you are performing an action that provokes an attack of opportunity. Even if she is, she is not able to see the opening and capitalize accurately enough to make the attack. She may not even know if you are a foe or a friend. Note that this has implications for blind attackers as well.

Moving Through Invisible Defender's Square (interpretation)
You may always choose to allow someone to pass through your square unharmed. If you are invisible, and someone is running around trying to find you, you may always lean to one side, press against a wall, duck, etc., to let that person go by you. Note that this different than the touch-attack rule (grabbing wildly at two squares worth of space to find someone). You may not combine the touch-attack rule with motion and try to run down a hallway flailing your arms to find someone invisible.

This is primarily a game-balance issue.

This rule is a guideline. Obviously there may be ways to bypass this (picking up a table that fills the entire hall and rushing down the hallway would likely uncover your invisible foe).

Invisibly Moving Through a Defender's Square (interpretation)
The rules describe only very specific reasons you may pass through a square held by someone who does not want you to pass through that square. Even when invisible, bypassing someone who is actively trying to hold a square is not simple – you must either tumble through her square or overrun her (an attack, which would normally dispel your invisibility).

In neither case, however, would the invisible character provoke an Attack of Opportunity. A failed tumble attempt, however, would mean the blocking character became aware of the attempt and blocked it – pinpointing your location. (Note that we play with a house-ruled tumble mechanic where a failed tumble attempt results in your being stopped if you tried to move through an enemy's square)

Firing in a Line to Hit Invisible Defender (house rule)
You must always choose a target square for an attack (if for no other reason than game balance).

If your invisible enemy is in that square, you attack normally but have a 50% chance of missing.

If an invisible character is between you and that square, that character provides cover to the square, however. Normally this would mean a +4 cover bonus to the AC of the target in that square, giving a range of attack rolls which would strike the cover and not the target. To simulate this (since there is no AC to add the +4 to), there is a flat 20% chance that your attack will strike the cover instead of reaching its square. Note that you must still bypass the armor class of the invisible character, but do not have to deal with concealment again. If you do not bypass the AC of the invisible character, you are not aware you had the chance to strike him.