Cost: Variable

Detect is an exotic mental/social Advantage that allows you to detect a specific substance or condition, even when it is shielded from the five human senses.



  • P106: Detect (Minerals; Smell-Based, -20%),
  • P135: Detect (Life) for Vampirism
  • P135: Detect (Water) for Water
  • P150: Detect (Magic; Analyzing, +100%; Short-Range 1, -10%)

PerksEdit discusses the GURPS Voodoo ability of spirits hearing own names, Christopher R. Rice references GURPS Horror 78

Anaraxes builds on Refplace's references to DF saying it's on page 25 of Summoners] and called Name Hearing

Pyramid 3/114 related



2011 via muninEdit

2011 post by munin which alleges this was a PM from Kromm

Detect says the "nearest significant source" but doesn't imply a single point or item. This means "some gold," "some people," and so on. The ability on p. 150 of Powers is meant to show how Analyzing narrows "some people" to "each person" by providing extra detail.

2015 via TMWEdit

2015 post by the_matrix_walker which alleges this was a PM from Kromm

TMW: Is it the intent of the rules for Detect that you can look past known sources and look for specifics, rather than just the "nearest significant source of the substance" without the benefit of Selective Effect?

Kromm: That's just a logical side effect of Analyzing, actually. The Cosmic included there means that IQ rolls for detailed analysis never fail, so you can instantly sort through all sources and know exactly what you've detected.

TMW: if a character is with his group of adventurers and has Detect Humans, but does not have Analyzing or Selective Effect, he cannot scan his local area for someone creeping around, because the closest significant source are the guys at the campfire?

Kromm: Sure he can. But now he has to roll vs. IQ for analysis – a simple Per roll for detection isn't enough. The point of Analyzing is that you don't have to attempt this roll . . . it's automatic. Adding Cosmic means that you don't even have to roll if the GM deems the necessary task to be "detailed analysis" rather than mere "analysis," which seems likely for "everybody in creation" but not for "everybody within tens of yards." The goal of my build in the quoted post was to anticipate all likely GM-imposed obstacles to be as over-the-top as possible.

TMW: I'm trying to determine if unmodified Detect can look past known sources, or narrow it's search parameters. Can the guy with Detect Humans look past his buddies and find someone lurking in the woods? Can someone with Detect Metal attempt to look specifically for gold? Does the use of Detect (actually detect all sources in range, but then) need a successful analysis roll to perform these feats? And if not, is Selective Effect the way to do those things?

Kromm: Detect can detect any subset within its purview – that's why broader forms of Detect cost more, not less. What allows this to work is not excluding a known source or specifying a subset before the search starts, but making the IQ roll for analysis afterward. The simplest way for the GM to handle this is to make the Per roll, look up the margin on the Size and Speed/Range Table to find the range, and then have an IQ roll assess the nature of any appropriate targets within that radius. The better the IQ roll, the more specific the details.
I don't see how Selective Effect really fits . . . That's for active area-effect abilities, while Detect is really no more such an ability than is hearing or smell. Just as abilities with the Discriminatory modifier can't have Selective Effect, I'd say Detect cannot by virtue of making Analyzing available.

TMW: So Detect can in fact pick up things other than the single closest significant source of what you are detecting? The Advantage listing doesn't really read like that...

Kromm: I think the existing wording makes for a lousy ability, to be honest. It also leads to stupid arguments . . . "Sure, you can use Detect (Metal) just as soon as you take off all your armor."

TMW: If I'm reading your response correctly, Detect finds all instances of your subject in sense range, and then analysis (be it by IQ roll or automatically with Analyzing) sorts all that out?

Kromm: That is correct. Honestly, would you pay 30 points for Detect (All Life) so that you can confirm that you have skin bacteria? Even with an "exclude known sources" clause, a jerk GM could have you detecting a mosquito on your helmet, a worm 10 cm from your boot, etc. I think the interpretation I gave is a lot fairer to players.


mentions at

Detect (Long-Range 2; Precise) is a nasty beast, since technically it'll let you sense something anywhere in the world with a straight Per roll. Anywhere.

see alsoEdit