Question on DC to detect invisible opponents


Rules Questions


In my next game, the group will be fighting several flying invisible sorcerers. The enemy's primary tactic is to stay at a distance of roughly 100ft and blast the group with fireballs.

I'm reviewing the invisibility rules and just thought I'd check if I'm reading everything correctly. The base DC to detect an invisible presence is 20. To pinpoint where the enemy is at is +20, so we're at 40. The distance adds another +10, so we're at 50. However, the noise of spellcasting gives a -20, so the total DC to pinpoint the enemy location for the PC's who don't have see invisibility is a 30. Sound right?


Unfavorable conditions (+2) or Impossible conditions (+5) as well as person making the check being distracted (+5) could push it up to 32 to 40.


If they know what they're fighting, the best tactic is not to be in that situation. Hit the enemy at their base and don't be out in the open when they're hunting for you. Do you mean you're the GM and they don't know what they're up against? Fireball has long range 400' + 40'/level. Against an invisible caster who is lurking in ambush with good visibility, they won't have a clue until they're hit. Of course, they're might be a sleepy sorcerer, tired of waiting issue.


I'm not sure if I want to apply unfavorable or impossible conditions, however, the possibility is there to be at a much further range, especially with the fireballs. So yes, I could have the sorcerers fly out quite a distance to increase the DC to 40+. I just wanted to make sure I had a clear understanding.

Some of the PCs have +20 to +27 on their Perception checks. Others have under +15, so for them it is going to be tough no matter what.

Yes, I am the DM. The group is in a war scenario, where the bulk of their allies are engaging a large force of the enemy hundreds of miles away. The PCs are on a mission to destroy the home base of the enemies strongest arcane support. Imagine a set of four towers perched precariously high in some arid mountains. The PCs are marching up to this position and have been fairly stealthy. They do know that they are up against fire-happy sorcerers, whose basic tactic is to apply protection from fire (and not worry about hitting each other in fireballs) and out-blast the enemy. The sorcerers will have a skeleton crew guarding the base, but it will still be a tough fight.

Then the reinforcements will start teleporting back once they know the base is under attack, but I'll roll randomly for that.


Be aware that fireball creates a visible projectile which the players can presumably spot as it leaves the sorc's square and/or trace the general direction of once it hits- although at 100ft this may be somewhat difficult due to the perception penalties.


Blakmane wrote:
Be aware that fireball creates a visible projectile which the players can presumably spot as it leaves the sorc's square and/or trace the general direction of once it hits- although at 100ft this may be somewhat difficult due to the perception penalties.

Very true. The sorcerers will be casting, then moving on their turn.


+20 Invisible
+20 Pin Point
+10 Distance 100'
+? Stealth Roll
-20 Sniping/Combat
------------------------
30+Stealth check to pinpoint
10+Stealth check to target area
--You could increase these by +5 because of the flying for favorable conditions.

Best defense would be:
See Invisible
Resist energy (20pts at 7th level)
Faerie Fire
Glitterdust
Hiding

Even spells like fog cloud, darkness could be used at points in space so the enemy can't see you.

---

Why are the PC's on foot? Shouldn't they be using Wind Walk and scouting from the air.


DC = Stealth check +20(invisible) +20(pinpoint DC) +10(distance 100') -20(combat) +/- movement modifier
= Steath check +30 +/- movement modifier

The Exchange

Stealth roll wouldn't be possible while casting I believe.

So DC is 20 + 10 for distance.

Remember to make flying checks for the casters too. It's 15 dc to remain stationary while flying in order to actually cast. I can't remember what the fly spell provides as the fly skill mod though.

Depending on the level of your party, Rangers and rogues could nail that DC pretty easily.

If those types then use tactics like shooting the target with glowing arrows or even burning missiles, everyone else can then see them too.

Just to state some things my players have done in the past against flying invisible enemies.


Wrath, if they are not using stealth then the check is...nonexistant.

Makes it rather easy. :)

The Exchange

actually you still need to make the check. The spell sets the base DC as 20 to notice the creature if they are moving, 40 if they are not. Invisible inanimate objects don't get to roll stealth, but invisibility still makes it hard to find them.

By your reasoning I could cast invis on a vase in an open field and a peasant could find it easily since its not trying to be stealthy.

The invis spell allows you to move around and do casty or shooty stuff and make it hard for your enemies to pinpoint you for retaliation. There's plenty of ways around it, but making it a non check to spot them because they cast a loud spell with a visual component isn't one of them.

Liberty's Edge

Pathfinder Companion Subscriber; Pathfinder Roleplaying Game Superscriber

Best solution for the party "I will ready an action to fire my bow/cast my area or ray spell at the square from which the the spell is cast". The guy with the ready action act just after the fireball is cast and before the sorcerer leave the square, so he don't need to pinpoint it.

RAW there is no way for you to miss from where the spell come, barring things like fog. Someone can argue that "A glowing, pea-sized bead" isn't visible in darkness as it don't have the light description, but the "glowing" part make it visible even if it don't illuminate the area around it.

At worst you will have a +10 to DC for range and a base value of -10 (Hear the sound of battle –10 [sure, it is hear, but there is no line for see a battle]). You don't need to see the caster, you need to see the streaking fireball.

The Exchange

You still have 50% miss chance due to invis, but your tactic gives them the square automatically at least.

That's better than just missing completely because you target the wrong square.


Wrath, please show me where I stated what you think I stated (ie: show me the quote that provides the reasoning you are referencing).

Let me be clear, if you are not using Stealth then you do not add stealth to your pinpoint DC. (Ie. the Stealth check is nonexistent.)
If you are using Stealth then you do add stealth to your pinpoint DC.

Hence, it becomes rather easy.

You stated they could not use stealth while casting thus indicating that in some way my post was incorrect because I included the stealth check.

If the stealth check is nonexistant the post is still correct.

For that matter, the spellcasters COULD be using stealth immediately preceding casting and that stealth check would continue to apply until the casting was completed.

The Exchange

Nah Gauss, just misinterpreted what you said. It read to me as if you didn't need a spot check if they weren't using stealth. I understand now where you're coming from.

Sczarni

@ Gray

Your best bet is in setting Perception DC to 30 as you suggested, but keep in mind that Invisibility gives bonus to Stealth in general.

More correct way would be for a creature to have +20 bonus on Stealth checks (if it's moving a half it's normal speed) coupled with a d20 roll for Stealth and grant -10 penalty on Perception checks for the distance of PCs, but in this case you can reach Perception DC as high as 50, which can make fight fairly difficult. I suggest forming the DC in accordance to your player's level.

Adam


Thanks for the feedback. This is all helpful, and we'll see how it plays out in about an hour.

I've taken the fly skill into consideration, and they should have no problem hovering. These particular opponents aren't really trying to be stealthy, but their leadership does have an idea of who the PCs are. Once they realize it is the PCs, they will back up and try to separate the party, but there will also be multiple combatants on the battlefield. So we'll see how they react.

The group is APL 15, (7 14th level PCs)but they really aren't optimizers by any means. I do a lot of coaching.


Splendor wrote:
Why are the PC's on foot? Shouldn't they be using Wind Walk and scouting from the air.

That's a great question. I think there are a few factors; the players are fairly new, and really don't optimize. They sometimes forget all the abilities that they have. Some of the players soured on scouting because it got them into trouble somewhere around 6th or 8th level. (Wizard scouted ahead, flying and invisible, and ran into an erinyes.


Well, the players surprised me and changed tactics. The oracle used ethereal jaunt to scout ahead as much as she could. There were places she couldn't enter due to wards, but she got a decent layout of the area, and guard placement. After reporting back to the group, one of the clerics and two martials then entered from a weak point via wind walk, put up a silence spell. The trio pretty much rolled well enough on stealth to take out all of the guards, and a majority of the opponents in the first two towers.

They didn't know that a couple of the guards had a telepathic link to leadership back at the main battle, but it took them some time to investigate. Fortunately, the wizard just randomly cast true seeing and happened to be in the right place to see several invisible combatants teleport into the area. I forgot the oracle also had access to true seeing, which she cast on everyone, thus negating my need to worry about invisibility at all.


Quote:
Very true. The sorcerers will be casting, then moving on their turn.

Don't forget moving has a penalty as well. -5 more for half speed (which would include stealthy movement, even though the stealth bonus overwhelms this it still stacks on) and -10 for full speed, which would include for a typical human a single move action of 30ft for instance. (he's standing still casting the spell, then jogging at full dash speed for 3 seconds).

Quote:
To pinpoint where the enemy is at is +20

Keep in mind also that you don't HAVE to ever pinpoint a creature to attack it. You only have to pinpoint if you desire confirmation from the GM about which square they are in guaranteed.

You can instead always just choose to GUESS though which square, without your GM confirming if you were correct, but if you guess correctly, you still hit him if you pass an additional 50% miss chance on top of whatever normal attack roll etc (including for magic missile). Or for an area spell like a fireball right back at him, you only have to guess right within 20 ft of course.

This is covered in the total concealment rules (which invisibility leads to).


Crimeo wrote:
Don't forget moving has a penalty as well. -5 more for half speed (which would include stealthy movement, even though the stealth bonus overwhelms this it still stacks on) and -10 for full speed, which would include for a typical human a single move action of 30ft for instance. (he's standing still casting the spell, then jogging at full dash speed for 3 seconds).

Though the fight is over, I don't think this would have applied. The -5 penalty is IF the flying invisible sorcerers were trying to use stealth. They weren't. They were just relying on invisibility, and the great distances they could have put between them and the PCs.


Gray, that is not true, check the invisibility rules on page 563.
If you are invisible and moving at half speed there is a -5 modifier to the perception DC.


Ah, I stand corrected. I forget there are about three places you need to check for invisibility/stealth/perception. Thanks.

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