Invisibility Revisited - Perception DCs

[The Mighty Thrar]

I am looking to see (through examples) if my interpretation on the Perception DC to (A) notice an invisible creature and (B) pinpoint an invisible creature.

Per the srd under Perception...
Noticing: A creature can generally notice the presence of an active invisible creature within 30 feet with a DC 20 Perception check.
Pinpointing: It's practically impossible (+20 DC) to pinpoint an invisible creature's location with a Perception check.

Perception DCs:
Perceive DC to Notice: 20
Perceive DC to Pinpoint Location: 40

Modifiers to Perception DC:
In combat or speaking -20
Moving half speed -5
Moving full speed -10
Running or charging -20
Not moving +20
Using Stealth +Stealth Check +20

SCENARIO 1 - Caster is Invisible and Silent
-Fighter PC is engaged in melee combat with monster.
-Caster PC has invisibility.
-Caster PC moves full speed.
-Caster PC arrives at a spot adjacent to the allied Fighter PC and within 10 feet of monster.
-Caster PC activates wand (pointing, non-verbal activation) and buffs/heals Fighter.
-Caster PC has a stealth skill bonus of 4
-Monster has a perception skill bonus of 4
Modifiers:
Moving full speed -10
Caster's Stealth check
Stealth ranks +4
Stealth check roll (an average roll) +11
Monster's stealth ranks -4
Total Modifiers: +1

Required rolls for
(Modified) Perceive DC to Notice +21
(Modified) Perceive DC to Pinpoint Location: +41

Results for creatures w/ equal opposing bonuses to stealth and perception:
(A) On an average roll, a silent caster would not be detected.
(B) A silent caster would be 'practically impossible' to pinpoint with a Perception check. Although 'actions' could be spent to pinpoint.

SCENARIO 2 - Caster is Invisible but 'In Combat or Speaking'
Same as Scenario 1 except that…
-Caster PC casts a spell with a verbal component
Required rolls for
(Modified) Perceive DC to Notice +1
(Modified) Perceive DC to Pinpoint Location: +21

Results for creatures w/ equal opposing bonuses to stealth and perception:
(A) Caster speaking or in combat w/in 30 feet is almost always 'noticed'.
(B) Caster speaking or in combat w/in 30 feet is still very difficult to pinpoint just through a Perception check.

So...
1-Does this rule interpretation seem correct?
2-In principle, does this seem balanced?

[concerro]

Thrar wrote:

I am looking to see (through examples) if my interpretation on the Perception DC to (A) notice an invisible creature and (B) pinpoint an invisible creature.

Per the srd under Perception...
Noticing: A creature can generally notice the presence of an active invisible creature within 30 feet with a DC 20 Perception check.
Pinpointing: It's practically impossible (+20 DC) to pinpoint an invisible creature's location with a Perception check.

Perception DCs:
Perceive DC to Notice: 20
Perceive DC to Pinpoint Location: 40

Modifiers to Perception DC:
In combat or speaking -20
Moving half speed -5
Moving full speed -10
Running or charging -20
Not moving +20
Using Stealth +Stealth Check +20

SCENARIO 1 - Caster is Invisible and Silent
-Fighter PC is engaged in melee combat with monster.
-Caster PC has invisibility.
-Caster PC moves full speed.
-Caster PC arrives at a spot adjacent to the allied Fighter PC and within 10 feet of monster.
-Caster PC activates wand (pointing, non-verbal activation) and buffs/heals Fighter.
-Caster PC has a stealth skill bonus of 4
-Monster has a perception skill bonus of 4
Modifiers:
Moving full speed -10
Caster's Stealth check
Stealth ranks +4
Stealth check roll (an average roll) +11
Monster's stealth ranks -4
Total Modifiers: +1

Required rolls for
(Modified) Perceive DC to Notice +21
(Modified) Perceive DC to Pinpoint Location: +41

Results for creatures w/ equal opposing bonuses to stealth and perception:
(A) On an average roll, a silent caster would not be detected.
(B) A silent caster would be 'practically impossible' to pinpoint with a Perception check. Although 'actions' could be spent to pinpoint.

SCENARIO 2 - Caster is Invisible but 'In Combat or Speaking'
Same as...

The example seems overly complicated but I think I understand the question.

It is only a DC 20 check period to notice that an invisible creature is in the area

PRD=A creature can generally notice the presence of an active invisible creature within 30 feet with a DC 20 Perception check.

Note
In combat or speaking –20 to stealth check

There is a table here.

If the caster is not speaking or is silenced, but has the metamagic feat that Silent Spell then you will have a hard time finding him.

Does that answer the question?

Yes, it is balanced. Invisible creatures should be nearly impossible to pinpoint.

[reefwood]

Thrar wrote:

I am looking to see (through examples) if my interpretation on the Perception DC to (A) notice an invisible creature and (B) pinpoint an invisible creature.

Per the srd under Perception...
Noticing: A creature can generally notice the presence of an active invisible creature within 30 feet with a DC 20 Perception check.
Pinpointing: It's practically impossible (+20 DC) to pinpoint an invisible creature's location with a Perception check.

Perception DCs:
Perceive DC to Notice: 20
Perceive DC to Pinpoint Location: 40

Modifiers to Perception DC:
In combat or speaking -20
Moving half speed -5
Moving full speed -10
Running or charging -20
Not moving +20
Using Stealth +Stealth Check +20

SCENARIO 1 - Caster is Invisible and Silent
-Fighter PC is engaged in melee combat with monster.
-Caster PC has invisibility.
-Caster PC moves full speed.
-Caster PC arrives at a spot adjacent to the allied Fighter PC and within 10 feet of monster.
-Caster PC activates wand (pointing, non-verbal activation) and buffs/heals Fighter.
-Caster PC has a stealth skill bonus of 4
-Monster has a perception skill bonus of 4
Modifiers:
Moving full speed -10
Caster's Stealth check
Stealth ranks +4
Stealth check roll (an average roll) +11
Monster's stealth ranks -4
Total Modifiers: +1

Required rolls for
(Modified) Perceive DC to Notice +21
(Modified) Perceive DC to Pinpoint Location: +41

Results for creatures w/ equal opposing bonuses to stealth and perception:
(A) On an average roll, a silent caster would not be detected.
(B) A silent caster would be 'practically impossible' to pinpoint with a Perception check. Although 'actions' could be spent to pinpoint.

This is what I get for Scenario 1:

Base DC 20
-10 full speed
-20 speaking (wand activation = spoken word)
+20 pinpoint

= Perception DC -10 to notice caster within 30 ft
= Perception DC 10 to pinpoint caster within 30 ft

Anything beyond 30 ft adds +1 to the DC per 10 ft.

Although, I suppose the argument could be made that each action requires a separate Perception check since the caster is not moving and speaking during the same action. In that case, it would be:

Base DC 20 -10 full speed = DC 10
Base DC 20 -20 speaking = DC 0

Perception DC 10 to notice the caster moving within 30 ft, and then, Perception DC 0 to notice the caster speaking within 30 ft, and it would be +20 to each one to pinpoint and +1 per 10 ft beyond 30 ft. I guess this does make more sense since moving and speaking are two separate actions in this case... but if he did move and speak at the same time for whatever reason, then both modifiers would apply.

Also, I'm not sure why the monster Stealth ranks are listed in your scenario...but maybe those are supposed to be the monster Perception ranks?

[Mojorat]

I dnt think the invis person gets the penalty for moving. invis itself already has this built I'n. if you stand still you get a much higher bonus. though I may be completely wrong.

it seems to me if the examples correct though the invisible caster actually gets no bonus.

so if moving is -10 casting is -20 .. what's the point of even having invis stealth rules then? I may be missing something.

[reefwood]

Mojorat wrote:

I dnt think the invis person gets the penalty for moving. invis itself already has this built I'n. if you stand still you get a much higher bonus. though I may be completely wrong.

it seems to me if the examples correct though the invisible caster actually gets no bonus.

so if moving is -10 casting is -20 .. what's the point of even having invis stealth rules then? I may be missing something.

The Invisibility section the back of the Core Rulebook (Glossary?) has all the info on invisibility and modifiers.

The -10 and -20 are modifiers, not DCs. If you're wondering why casting while invisible is DC -20? It is not. The base Perception DC is DC 20 to notice someone invisible within 30 ft. It is DC 40 to pinpoint the square. Moving at full speed applies a -10 penalty to these DCs, and casting with a verbal component (or spell trigger word, or command word, etc) applies a -20 penalty to these DCs.

If you are making a Stealth check while invisible, that is what the Perception check is going against, and you add +20 to your Stealth check. Essentially, it's like your Stealth check is modifying the case DC 20 for being invisible. So, if your Stealth result is 18, the Perception DC is 38 to notice and DC 58 to pinpoint.

[Asphesteros]

Yea, all the modifiers between the chart in the glossary and under perception skill, and stealth skill make this way more convoluded than is has to be. Consolidating everything, I believe the master mod chart would boil down to this:

Base DC to notice a visible creature: DC0

Tally all applicable modifyers:

Creature is Invisibile: +20
Not moving or making noise: +20 (NB - eratta on glossary chart)
Moving but using Stealth: +Stealth Check
Distance: +1/10ft
Behind obsticle like a door: +5
Behind obsticle like a wall: +15 (18" wall) or +10 per foot
Other unfavorable conditions: +2 (e.g. interfering background noise)
Other terrible conditions: +5 (e.g. cacophinous noise)
Observer distracted: +5
Observer asleep: +10

Creature moving half speed: -5
Creature moving full speed: -10
Creature speaking, running, or charging or otherwise in combat: -20
Other favorable conditions: -2 (e.g. maybe heavy dust on the floor)

And Finally,

To identify the square an invisible creature is in: +20

SO

Scenario 1 - Monster to observe invisible caster:
Base DC20 (0+invisbility)
---Caster rolls a 14 on stealth (10+4): +14
---Fighter in melee with monster: +2 for unfavorable condition, maybe even +5 (for distracted if the moster was previously unaware of the caster at all)
---Wand is a spell trigger item requiring a spoken word, also arguably the wand's effect and use in combat alone qualifies as being in combat: -20 (this trumps the movement mod)

SO, monster's DC to notice the caster at all is 20+14+2(or+5)-20
= 16 or 19
To pinpoint the Caster's Square DC= 36 or 39

The monster would have to roll at least a 12 to realise there's an invisible caster around, and the noise and disturbance of the casting wasn't coming from some magic the fighter used or some other reason.

And he'd have to roll a natual 20 to actually perceive exactly where the caster was.

Scenario 2 is actually the same as Scenario 1 - but lets say the caster was casting a meta-magic silent spell in 1 so could remain quiet. Since light still emanates from an invisible source any magical glitter from the spell's casting could still be visible and count as 'in combat', regardless the magical forces still express themselves even if not glittery, so could likewise give away position same as an invisible swordswing could. It's up to the DM. For myself, I would count any spell or attack as 'in combat', unless it specifically indicates otherwise (like a su ability) though would allow the stealth check to minimise the penalty.

[The Mighty Thrar]

Thanks, Asphesteros and the rest. That clears it up.