How a ****ing cantrip exterminates an entire school of magic. NO MORE OF THAT!

[Crothian]

Try taking some ranks in Spot and Listen. It's the schnizzle.

Seriously, though, if you are in a mysterious room / area that somehow puts you on the alert - Detect Magic can often avoid a nasty surprise.

So, almost every room in a typical dungeon environment? All it takes is two encounters like that to get rid of all of the Wizard's detect magics and 3 encounters for the Sorcerer. One spell before the encounter and one spell after eats up spells really fast.

 

[Jack Simth]

I mentioned it a few pages earlier, but it bears repeating.

For those asking who would prepare a large amount of Detect Magic spells each day...

Warlock gets Detect Magic as an at-will ability at level 2. Regardless of what you guys decide how this goes, there is an entire class that will be able to exploit whatever it is you conclude.

There's a number of ways to have what is effectively at-will Detect Magic, each of which costs a different set of resources.

Permanency + Detect Magic (500 xp, requires minimum level 9).
Persistent Spell + Detect Magic (this is actually the example used in Persistent Spell) (two feats - which are also used for other things - and a 6th level spell slot 1/day; usually doable at 11th).
Vatic Gaze (PHB II; requires arcane caster level 9 and a feat slot)
Magic Sensitive Reserve Feat (Complete Mage; requires a feat slot, the ability to cast 3rd level spells, and requires that you keep prepared (or know and keep a slot of that level avaialble) a Divination spell of 3rd+)
Warlock-2 (requires spending two levels on Warlock - which you mentioned)
Others (Custom items, wands, playing Pathfinder, certain funny races, et cetera).

Please tell me, how you describe (as a DM) a pebble going through an illusionary wall to the player who threw it and is paying attention to the result.

?

Let me try:

"The pebble just vanished into the stone... perhaps even faster than a hot knife cutting into butter. But the rocky surface did not react. Bizarrely, the sound of the pebble hitting on the stony surface was...late. It was heard only after the small piece of rock had disappeared into the cave's wall for good..."

Now IMHO opinion this is a decent, impartial, description of the effect an attentative PC experiences.

In certain cases, yes - specifically, in the case where there's exactly nothing on the other side of the wall, the person who put the illusion there isn't paying attention, and so on. As noted by Greenfield, if the caster's there, the caster can cause the illusion to keep pace.

Additionally, if there's a solid surface behind the illusory wall (perhaps a door of similar material to the wall, which is flush with the wall, much like, oh, a car door), then the pebble makes about the right sound, bounces, and hits the floor. Sure, you maybe get your interaction will save, but not proof. And, of course, if the dungeon includes real traps, and you use Illusory Wall, Phantom Trap, and other things that would leave an aura of illusion a lot, many of which are specifically set up to draw prying hands to the real traps (others of which aren't), then anyone who tries to lay hands on everything that has an illusion aura is soon dead by attrition.

What's also fun is using Veil on incorporeal undead: "The pebble passed right through. Must not be real. Ignore it, keep looking for the illusiAUCH!"

There's other things you can do... it's just that when opposed, you need to get a little bit creative with what you're doing.

Now in my book this is enough proof to disbelieve an Illusion. Even more, I think this is proof that the illusion isn't real, thus making the save worthless. But even if you argue that the PC does not have enough proof to know that the illusion isn't real (??? - I 'm wandering how you could sell that to the players - ???) and you allow for a save... The PC will eventually get to it, either by trying again, either by throwing bigger things... either by poking it at close distance... EVENTUALLY he will know for sure.

So don't give them that time. Arrange for consequences for poking every random thing.

Really, this is a problem with illusions in general, and is irrespective of Detect Magic. Someone who pokes everything because it might be an illusion isn't going to need Detect Magic to have this effect. Arrange for poking random stuff to not be feasible. Traps that react to being poked is one of the simpler methods.

....So much for a 6th - 5th - 4th level Illusion spell... and it all started because of a cantrip detecting it without a sweat.

A thrown rock would have detected it without a sweat, too, and saved you the spell slot, in as empty an environment as you appear to assume it's in.

 

[Greenfield]

I'm going to repeat an earlier suggestion: Invent a new feat : Mask Illusion

Prerequisite: Illusion specialization, Spellcraft 5 ranks, Int 15 minimum

Benefit: When casting visual illusions, you are able to include a "magical signature" in them so that they radiate some other school of magic when viewed with Detect Magic or Arcane Sight.

The caster must choose this aura at the time the illusion is created. This illusion, like any other, can be penetrated if examined carefully. The DM may call for contested Spellcraft rolls between caster and observer if the observer has reason to suspect that the magical aura is false.

The contested Spellcraft rolls are always called for if the caster attempts to suppress the magical aura entirely.

A feat like this allows the dedicated Illusionist to practice their craft without having to fear the first magical apprentice who comes along.

 

[Dandu]

Feat unnecessary

 

[Jack Simth]

Feat unnecessary

That only gets you creatures and objects, though... which, granted, gets you a very large number of illusion spells. There are 47 Illusion spells in main section of the SRD; of those, only 16 produce an effect that meets the dual criteria of "knowing it's an illusion matters" and "can't be guarded via one or the other of those two spells". Of those 16, one doesn't have a local effect (False Vision) and so it doesn't really matter as far as Detect Magic and it's ilk go. Two don't have visual elements (Ghost Sound, Ventriloquism). Two also affect a guard able creature (Mislead, Mirror Image) and creative use of Magic Aura and Misdirection can be used so that knowing there's an illusion about doesn't really help. So between Magic Aura, Misdirection, and some minor trickery, the only ones left as dead giveaways (out of 47 spells of the Illusion school in the SRD, mind), we have:

Hallucinatory Terrain
Illusory Wall
Mirage Arcana
Minor Image
Major Image
Silent Image
Permanent Image
Persistent Image
Programmed Image
Screen
Silent Image

11 spells that can be foiled via the cantrip in question. And there's ways to make that difficult, too; if the entire area is covered in, say, Screen (or even just Hallucinatory Terrain), then the aura of illusion will be there, regardless of other considerations, and so you'll effectively white out Detect Magic, rendering it useless for the purpose of noting other illusions.

Less than 25% of a school is an entire school, apparently, and a 4th level spell can fix even that (although you'll have to Heighten it for some of them, as you need the aura coating the big area to be at least as strong as the auras you're wanting to actually use).


Edit:
Come to think of it, Hallucinatory Terrain is probably the RAW counter needed, handling both Detect Magic and Arcane Sight (but not Greater Arcane Sight or True Seeing). 4th level spell, so grants everything in it's area a Moderate aura of Illusion (if you need to mask stronger auras, Heighten it to 7th). Lasts 2 hours/level, and has a stupidly huge area (one shapable 30-foot cube per level. Shapeable effects can squeeze down to ten foot cubes. So that's effectively 27 10-foot cubes per level).

 

[Greenfield]

The spells are useful in a lot of cases. In fact I modeled the proposed feat on Magic Aura.

The problem is, you can't cast the second spell while maintaining concentration on the first, so an awful lot of the Illusion spells can't be helped that way.

And of course you can't mask or substitute the aura of one object or creature with your illusion, since the illusion is neither an object nor creature.

As for "whiting out" the area with a broader illusion, it doesn't work. Detect Magic reveals the number, location and nature of all the magical auras in the area. It sees right through your whiteout.

The illusion most likely to be encountered in a dungeon, of course, will be Permanent Image, which you can cast the second spell on (presuming it qualifies as an object or creature), but the masking spells aren't permanent and are unlikely to have survived the years since whatever it was that turned the place being explored into ancient ruins of the type that attract adventurers.

So you might be able to mask a very few illusions with the spells suggested, but I still think the feat is an appropriate solution. YMMV, of course.

 

[Jack Simth]

As for "whiting out" the area with a broader illusion, it doesn't work. Detect Magic reveals the number, location and nature of all the magical auras in the area. It sees right through your whiteout.

Per Detect Magic

Magical areas, multiple types of magic, or strong local magical emanations may distort or conceal weaker auras.

So just get it up to a category or two above the ones you're covering, possibly even using a completely different school of magic. A Heightened Forbiddance, maybe, for something Permanent.

As to concentration: There's a spell for that in Spell Compendium: Sonorous Hum.

 

[RUMBLETiGER]

Let me offer a different perspective, Jimlock. You claim that the entire Illusion tree of magic is rendered useless by Detect Magic. What if it is?

My response is to challenge your fundamental assertion that this is a bad thing or somehow wrong. I see nothing wrong with the proposition that a 0 level spell is proof against a line of magic that is based on illusions. Considering that most creatures and the majority of classes will not have detect magic at will, illusions will be very effective in many cases. I have no issue with 1st level casters being able to protect their party from illusions.

I kinda think that would be a big deal and a bad thing.
Neuters the Beguiler class quite a bit. And such.
I do, however, think this is something that could be worked out between a DM and players, without needing this level of meticulous discussion. But I get why Jimlock is concerned.

For example, while Player A is spending his 3 rounds narrowing down the details of what he's detecting, the DM can have a monster burst out of the illusionary wall and blow his concentration. or a trap, or whatnot.

 

[Arrowhawk]

I kinda think that would be a big deal and a bad thing.
Neuters the Beguiler class quite a bit.

The funny think about this comment is that, imo, it underscores the problem with the tier system and how it is based on assumptions that are not necessarily true. The reality is that since Detect Magic can be made permanent, there would be a whole truck load of individuals who deal with adventures and spell castes who would have had this cast upon themselves. It would be like people who drive a tow truck....buying a winch.

Yeah, there should be all kinds of things out in the real world with methods for detecting the use of magic and thus keeping magic and its use from so quickly dominating the world.

Probably a bit off topic here, but eh.

 

[kitcik]

So, almost every room in a typical dungeon environment? All it takes is two encounters like that to get rid of all of the Wizard's detect magics and 3 encounters for the Sorcerer. One spell before the encounter and one spell after eats up spells really fast.

Although back in the day (78 - early 80s), there was such a thing as a "typical dungeon environment," I find this is not the case in games today. Also, zero level spells are pretty plentiful.

With 2 casters in the party, we easily have enough Detect Magics for a typical day's worth of events.

As a non-caster, I have a hand signal that quietly requests a DM be cast. I make that signal a lot.