Detect Magic v. Invisibility & Glyphs

[Gizzard]

One of my players pointed out that Invisibility does not say anything about supressing it's own magical emanations; he wanted to be able to "see" magically Invisible creatures by using his permenant Detect Magic. This seems to violate the spirit of the spell, but is it legal in 3.5E?

Similarly, he wanted to detect Glyphs of Warding and Symbols with his Detect Magic. Is there any situation under which the player will not set off the Symbol or Glyph by detecting it? (Other than by not being a specified target?) I notice that Read Magic has some DCs associated with reading various Glyphs etc, is there some situation where you can Read a Glyph without triggering it?

 

[Tessarael]

As I understand it, Detect Magic can detect all these things. There have been other threads on Detect Magic and Invisibility - in this situation, Detect Invisibility is much better (you can see them!).

Looking at Detect Magic: it's range is 60' and it has a cone-shaped emanation. If the there is magic (e.g. a Glyph, Symbol, or magically Invisible person) in that cone, than in the first round, yes there's something magical. Round 2: you find out the number of auras and power of the most potent aura. Round 3: you find out the location and strength of each aura. So if the magically invisible thing is stationary, you can locate which square it is in - otherwise it might well move in and out of your cone (particularly if they notice you casting Detect Magic).

Will you set off a Glyph? Let's look at the SRD ... Glyph of Warding affects object touched or 5 square foot/level. So as long as you don't do Detect Magic, or Read Magic in that area, you'll be fine. However as a DM, I would rule that you need to be fairly close to a glyph to read it ... Read magic doesn't trigger it - but being near enough to read the Glyph would if you meet the trigger condition and you're within the area.

Will you set off a Symbol? First, a symbol is visible and legible at a distance of 60' - it can be covered or hidden, Detect Magic penetrates 1' of stone, 1" of metal, a thin sheet of lead, 3' of wood or dirt. If the trigger for the symbol is looking at it, then yes to be in range of Detect Magic, it's 60', so it goes off. Now if the Detect Magic was cast with extended range, it would avoid this.

That's my understanding ...

 

[Thanee]

Yeah, the big problem with detect magic is, that you need to concentrate on the spell to gain information. And you need to concentrate for 3 consecutive rounds to gain accurate information.

Sure, a still-standing invisible whatever can easily be detected with the spell, but a moving one isn't that easy to catch. During the first round you'll only know "something is there", you'll not know that it is moving or anything. If it leaves the cone, then you'll only know that the aura has vanished. No reason given.

Anyways, I'm pretty sure, that Detect Magic does not equal "seeing magical auras" but "sensing magical auras". You know they are there, but you cannot actually see them (well maybe after three rounds you can). That's at least how I understand it. If you look at the location you detected a magical aura at, you can see what the source of the aura is. A symbol is probably triggered at that point. A glyph AFAIK is only triggered, if you get close enough, but looking at it does not trigger it.

Arcane Sight OTOH simply highlights magical auras in your field of vision.

Bye
Thanee

 

[Darklone]

It's much worse with the thousands of lingering auras in a high magic campaign... and a good reason for an invisible dude to raise Hide and Move Silently as well.