That would mage magic traps useless.
Ways to prevent Detect Magic from detecting a magic trap:
1) Hide the magic behind something that detect magic cannot penetrate.
2) Include a nondetection spell in the construction of the trap.
3) Hide the dangerous magic underneath a more powerful but pointless magic.
4) Just for fun, hide a dangerous mechanical trap under a not so dangerous magical trap. (Not exactly prevention, but fun all the same.)
Magic traps CAN be detected by detect magic. That does not negate the trap. Remember, the player must spend 3 rounds to locate the magic.
Player: I am walking along detecting magic.
GM: ok that means you cannot walk more than a single move action per round and you must walk in front so as not to see all of your allies magic items. (Thier magic items will constantly count as 'presence of magical auras' and will thus read as false positives)
Player: Ok
*time passes*
GM: You detect the presence of magic.
Player: I stop moving
GM: round 2, you detect the strength of the magic and the number of sources. (Tells him that information)
Player: Ok
GM: Round 3: You see the door to the side has magic upon it.
Player: I make a skill check to see what type.
GM: Abjuration
Player: Ok.
Now the player can try to dispel it..or not.
What is the trap? An abjuration effect at a slightly higher level than the magical trap. The Abjuration masks the trap.
Player dispels the abjuration. The magical trap remains. Player may now choose to detect again or to try the door. Either way, the player is burning resources (assuming another dispel magic if he detects more magic).
- Gauss
Edit: Just remember, the person using Detect Magic needs to be out front. Otherwise it will take him 3 rounds to scan the area ahead just to be able to separate his allies magic from the magic of any potential traps.
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At the end of the day, the important thing to remember is that traps are really meant to be detected. It's the disarming part that's meant to be the challenge. Players not finding traps is just terrible dice rolls or people not playing smart.
If you're trying to make a trap that can't be detected and/or is just there to do random damage to the PCs, it's not a "trap", it's just doing damage to the players. You might as well just have them take 2d6 points of damage in the morning cause you feel like it.
Robb: Good point. :) Just like any other encounter traps are meant to be interesting and force the players to think and use resources. Just because they use detect magic to find one does not give them automatic mastery over traps.
- Gauss
Sounds pretty nice to me Gauss & Robb.
Do you think the aura could be analyse with spellcraft to determine wich spell is on ? Or as the spell is not cast for the moment it is impossible to get it ?
No, that would require something like Analyze Dweomer. Identifying the specific spell is beyond the power of a mere 0th level Detect Magic
First: It is not spellcraft you need but Knowledge Arcana.
Second: No, you cannot use Detect Magic and Knowledge Arcana identify the magic trap or spell. You can only identify the school of magic.
You can also determine the strength of the magic (compare the spell level and caster level to the chart on CRB p267 and see which one gives a higher reading then inform the player of this and let him draw his own conclusions).
And in case you didnt catch my edit earlier:
Just remember, the person using Detect Magic needs to be out front. Otherwise it will take him 3 rounds to scan the area ahead just to be able to separate his allies magic from the magic of any potential traps.
- Gauss
Lanassa: I slightly mispoke. I was meaning pre-existing abjurations with no physical effects.
To identify a spell in place you must be able to interact with the spell somehow. See it, experience it. An intangible abjuration that has no physically identifiable effect cannot be identified this way.
You can identify a pre-existing Wall of Fire. You cannot identify a pre-existing Alarm spell.
And you are right, it is a bit vague. This is my understanding (which may be incorrect but it seems reasonable to me).
- Gauss
I think you can identify visible spell effects such as a cloud kill spell.
If all you can see is an aura there is no way to really know which spell it is. It is highly possible that someone that used a conjuration spell just left since auras linger after a spell is cast.
As an example if I cast a mirror image spell, and then walk off the aura will be around for a little while.
It should end the magic on the trap completely.
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Now the player can try to dispel it..or not.What is the trap? An abjuration effect at a slightly higher level than the magical trap. The Abjuration masks the trap.
Player dispels the abjuration. The magical trap remains. Player may now choose to detect again or to try the door. Either way, the player is burning resources (assuming another dispel magic if he detects more magic).
/sigh
People overanalyze everthing. Once a mage finds magic on a door he backs down the hall and uses the open cantrip, mage hand, or sends in a sacrificial level 1 summons.
If stealth is a necessity, silence is a lesser resource than dispell and far more reliable.
As for non-magical traps: mages can be just as perceptive as anyone else.
Artanthos: none of those three will undo a lock. And none of those three will take care of a magical trap that resets.
Silence has no bearing on magical traps that I am familiar with.
Yes, you are correct about non-magical traps and perception. But if the person walking down the hall is using detect magic then that person is not trying to detect a mechanical trap.
- Gauss
Traps and magic traps are hidden from detection using any number of ways. Lead, magic aura, simple geography (like around a corner/ledge), etc.
Also detect magic round 1 is merely presence or absence in a 60' cone. It's not a magic radar.
Tiny Coffee Golem: That is why I stated the person using detect magic has to be out front.
Cleric (using detect magic) is walking around.
If he is out front he can walk (single move actions) and the moment he detects magic he stops and pinpoints it (takes 2 more rounds).
If he is NOT out front he will constantly be detecting his allies magic and as a result will have to spend 3 rounds each time just to see where the magic is. This will wind up taking alot of time.
Also: if the entire area is suffused with magic then he would have to use the 3 round method.
- Gauss
Wouldn't one of the easiest ways to make a magic trap be undetectable is to put it out of range of a Detect Magic? Using Arcane Eye of True Seeing to set it off allows you to put the trap at one end of a 80' corridor (for instance) that casts Fireball centered at the corner the party has just gone around. Since Detect Magic has a 60' range it would go off before they were close enough to see it. Even using Detect Good to set off the trap would activate it before a good aligned caster could do more than 1 round of Detect Magic before it went off.
I've thought of this. How would such a trap be disabled by a Rogue? Can a Rogue disable a trap 80' away?
Given the above trap, the rogue would have to make a Detect Traps/Perception roll from outside its 120' visual range, if possible (-13 at best). Then would have to have some way of sneaking up to it, Invisibility against Arcane Eye, sneak up to it and then disable it.Wouldn't one of the easiest ways to make a magic trap be undetectable is to put it out of range of a Detect Magic? Using Arcane Eye of True Seeing to set it off allows you to put the trap at one end of a 80' corridor (for instance) that casts Fireball centered at the corner the party has just gone around. Since Detect Magic has a 60' range it would go off before they were close enough to see it. Even using Detect Good to set off the trap would activate it before a good aligned caster could do more than 1 round of Detect Magic before it went off.I've thought of this. How would such a trap be disabled by a Rogue? Can a Rogue disable a trap 80' away?
So, pretty much un-disarmable.
A trap with Arcane Eye has a +20 Perception bonus. A level 9 rogue can easily have a +23 stealth bonus (9ranks, +3trained, +6dex, +5competence bonus). Without invisibility the Arcane Eye would need to roll 3 points higher than the rogue. With invisibility the Arcane Eye would have no chance of detecting the rogue.
Note: Dont forget the -1 perception penalty for each 10feet.
- Gauss
Tiny Coffee Golem: That is why I stated the person using detect magic has to be out front.
Cleric (using detect magic) is walking around.
If he is out front he can walk (single move actions) and the moment he detects magic he stops and pinpoints it (takes 2 more rounds).
If he is NOT out front he will constantly be detecting his allies magic and as a result will have to spend 3 rounds each time just to see where the magic is. This will wind up taking alot of time.
Also: if the entire area is suffused with magic then he would have to use the 3 round method.
- Gauss
Thin sheet of lead over the mechanism so the LOS is blocked until it's too late and the trap goes off. Cleric =X Trap =t You'll have to forgive my lack of artistic skill, but if the cleric is walking down the hallway and the magic trap is slightly set back with a little sheet of lead blocking detection LOS until he's in the blast zone. It's mundane yet effective in explaining why rogues aren't completely useless and the reasoning behind Trapfinding.
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Edit: and the formatting doesn't keep.
Tiny Coffee Golem, if you will note earlier in this thread I stated a number of methods for blocking detect magic.
My post that you quoted is a reason why the person using detect magic had to be out front.
- Gauss
Tiny Coffee Golem, if you will note earlier in this thread I stated a number of methods for blocking detect magic.
My post that you quoted is a reason why the person using detect magic had to be out front.
- Gauss
I misunderstood. sorry.
Another way to hide magical traps is to place a lot of Magic Mouths all over the place, with activations set to be pretty much impossible (dancing pink elephant).
Have the magic trap set up so that there is a mechanical traps 5' or 10' before the magical one, which may be missed while the rogue is concentrating on the magical one.
Have an illusionary wall cover a symbol of (your preference). When the mage detects the illusion, there is a good chance that they will dispel it and reveal the symbol - which will cause it to activate.
A trap with Arcane Eye has a +20 Perception bonus. A level 9 rogue can easily have a +23 stealth bonus (9ranks, +3trained, +6dex, +5competence bonus). Without invisibility the Arcane Eye would need to roll 3 points higher than the rogue. With invisibility the Arcane Eye would have no chance of detecting the rogue.
Note: Dont forget the -1 perception penalty for each 10feet.
- Gauss
A Rouge can't stealth without concealment, True Seeing sees through darkness and invisibility, So the Rogue would need Invisibility AND Non-Detection always up unless he can spot the trap from over 120' away (beyond the range of a sunrod even with low-light vision and nearly all forms of darkvision) and make the DC 43+ perception check, which is rather impossible for most low-mid level Rogues that might expect to encounter a CR 6 Cloudkill trap w/true seeing.
Quantum Steve:
First, I was talking about Arcane Eye not true seeing.
Second, a trap with True Seeing should not be thrown against low-mid level rogues. If that occurs the problem is with the GM and not with the party. The first example of a trap with true seeing is at CR10.
Against a CR10 group True Seeing is not easy to bypass but it CAN be done. As you noted, nondetection is available and when cast at level 10 has a reasonable chance of bypassing True Seeing. It has a 1hr/level duration so is not hard to keep cast. Additionally, true seeing cannot penetrate a fog. Any number of fog spells or effects will allow the rogue to sneak up to the trap.
Edit: Regarding light sources? That one is easy. If the rogue is interested in using light all he has to do is shoot an arrow with light on it down the hallway. Oh, and a bullseye lantern has a range of 60foot bright and 120foot dim. IE: 120bright and 240dim with low-light vision.
- Gauss
P.S. Rouge cannot stealth at all since it is makeup. *grins*
Quantum Steve:
First, I was talking about Arcane Eye not true seeing.
Second, a trap with True Seeing should not be thrown against low-mid level rogues. If that occurs the problem is with the GM and not with the party. The first example of a trap with true seeing is at CR10.
Against a CR10 group True Seeing is not easy to bypass but it CAN be done. As you noted, nondetection is available and when cast at level 10 has a reasonable chance of bypassing True Seeing. It has a 1hr/level duration so is not hard to keep cast. Additionally, true seeing cannot penetrate a fog. Any number of fog spells or effects will allow the rogue to sneak up to the trap.
Edit: Regarding light sources? That one is easy. If the rogue is interested in using light all he has to do is shoot an arrow with light on it down the hallway. Oh, and a bullseye lantern has a range of 60foot bright and 120foot dim. IE: 120bright and 240dim with low-light vision.
- Gauss
P.S. Rouge cannot stealth at all since it is makeup. *grins*
OK level 10 party, then.
The Rogue can have Non-Detection up all day, but not Invisibility. He'll have to cast it before sneaking up to the trap.
First, he has to be able to see the trap. So, he can spend several rounds in each room or corridor shooting arrows everywhere he can't see (just in case there's a trap), likely alerting all creatures two room away or more to his presence, or have LLV and a bullseye lantern. Is there a penalty for perception checks into dim light?
Next, he has to "find" the trap. That CR 10 you mentioned has a Perception DC of 34. So, with the distance modifiers, that's a minimum of DC 46.
10 ranks + 3 Class + 5 Trap Finding + 2 Wisdom + 5 Circumstance + Take 20 = 45
Wisdom is not high priority for Rogues Who also need Dex, Str (if the want to melee), Con, Int for skills, and Cha to face. Actually, many Rogues might dump Wis entirely and rely on Iron Will and Slippery Mind for saves, and their copious skill ranks for Perception and other WIS based skills. A 14 Wisdom is being pretty generous.
So, unless the Rogue has a decent Wis AND spends a feat on Perception AND buys a +5 item, he can't spot the trap on a 20 from that distance. And if he's not a Rogue (i.e. doesn't have trap finding)?
Forgedaboudit!
A DC 46 is a pretty unreasonable DC at 10th level.
Oh, and then he has to use 2 spells for every CR 10 trap he comes across.
And if it's a double trap with a Arcane Sight proximity tripped Invisibility Purge, it's undefeatable.
Come to think of it, how does a Rogue defeat a proximity trigger?
Quantum Steve: Nondetection will make it so that true seeing is completely and totally nullified (assuming it fails the caster level check). It will be completely unable to detect the rogue.
- Gauss
Quantum Steve: Nondetection will make it so that true seeing is completely and totally nullified (assuming it fails the caster level check). It will be completely unable to detect the rogue.
- Gauss
Your right, I totally forgot about that, thanks.
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Non-Detection gives a Caster Level Check.
The CR 10 trap in question utilizes Energy Drain, a 9th level spell, so the minimum CL for True Seeing is CL 17. The trap has to roll a 4 to detect the Rogue.
Quantum Steve: Good point. But for traps that are not utilizing Energy Drain the CL would be lower.
- Gauss