Detect

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.

Base Cost

Commonality	Examples	Base Cost
Rare	Sorceresses, fire magic, zombies, gold, radar, radio	[5]
Occasional	Spellcasters, magic, undead, precious metal, electric fields, magnetic fields, radar and radio	[10]
Common	Humans, supernatural phenomena, supernatural beings, metal, electric and magnetic fields	[20]
Very Common	All life, all supernatural phenomena and beings, all minerals, all energy	[30]

Selective Effect

PU4p16:

allows the user to narrow the range of what he’s looking for, whether to simply limit the class of substances or to pare the search down to a single, specific subject.

Special Enhancement

• Analyzing (+100%)
• Area Sense from Totems and Nature Spirits

Forma

• Extended Senses (0%)
• Para-Sense
• Supernatural Awareness

Examples

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

Perks

http://forums.sjgames.com/showthread.php?t=159805 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

quotes

Kromm

Kromm in 2006

http://forums.sjgames.com/showpost.php?p=323140&postcount=22

Consider Detect (Supernatural) . . . Unless modified to be magical, it isn't, and won't be blocked by magic or antimagic.

This was a reply to molokh asking:

I don't quite understand how something other than magic detect Obscure (Magic...), unless it's Detect (Obscure). Could you elaborate?

2011 via munin

2011 post by munin which alleges this was a PM from Kromm http://forums.sjgames.com/showpost.php?p=1228100&postcount=10

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.

References

2015 via TMW

2015 post by the_matrix_walker which alleges this was a PM from Kromm http://forums.sjgames.com/showpost.php?p=1858235&postcount=20

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.

PK

mentions at http://forums.sjgames.com/showpost.php?p=354373&postcount=12

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.

Analysis

PK's summary underepresents it in one regard: it's anywhere in the UNIVERSE, but to any who read "world" as "planet" this might give a false impression.

• PK is being consistent with GURPS terms though, because it is not INTERDIMENSIONAL. Crossing dimensions is called World Jumper in GURPS, and acting across dimensions is called World-Spanning.

PK's summary OVERrepresents it in another regard: he neglected to specify (but probably implied) "at the current time". Due to modifiers like Time-Spanning being able to detect things/conditions in the past/future this is important, especially with things like Time Jumper being a thing in GURPS.

The distinction here is that Detect has no listed "Range" or "Max" which leaves 2 interpretations:

• per B101 assume that range is 100 yards since "exceptions will be noted"
  • one benefit to this is points can be gained via Minimum Range or Reduced Range limitations.
  • one drawback to this is the requirement to buy Increased Range to detect things beyond 100 yards
• assume there is unlimited range (no "hard cap") but that there is a "soft cap" by the use of range modifiers

If the latter is true, then the soft cap would be lost via "no penalties" going beyond the LDM tier. To instate SOME form of cap would require some imagination. One would be to use Warp as a precedent. B99 has Range Limit for it. This limitation has tiered value based on the distance penalties unique to warp on B98.

Warp only prohibits Reduced Fatigue / Reduced Time, so in theory you could take Reduced Range atop the -50% max range which instates 10 yards, to get even smaller ranges. Or add "increased range" to modify the max range instated by that.

Hyperjump is effectively a "Minimum Range" WITHOUT a maximum range as another approach. It instates a minimum range of a light-second (186,000 miles) which is beyond what you can get points for using Range Limit:

"A range limit of more than 100,000 miles is not a meaningful limitation."

In theory Range Limit could have finer granularity though. Like for example if -50% for 10 yards and -45% for 20 yards, it could be reasonable to increment at 2 yards per 1% (49=12 48=14 47=16 46=18) to allow interstitial maximums.

Taking directly from Warp's table seems like the most balanced, because if it's based on penalties then reducing to no distance penalties means gaining -50% at unlimited ranges. The point of the formula is that ascending penalties reduce the value of 50%. This might work for applying it to the Mal1/2/3 tiers but not for unlimited distance.

One rule of thumb that could be adapted from the Maintain Spell rule (if "free", each 1 energy will last 5 maintenance periods) is to look at the usual cutoff for Range Limit and then quintuple it. So to get -5% for something that causes a -9 penalty, this is 9 yards for Mal1, 70 yards for speed/range, 10,000 miles for LDM (B241) and 100,000 miles for Warp (Warp is initially higher-penalty than LDM but is lower-penalty at higher distances, at -1 per x10 instead of -2 per x10) so if you base x50 on 10k then it's 50,000. If you base it on Warp, it's 500,000.

HYPERJUMP (98-99) has two values depending on the "speed". There is a time delay. There are other limits such as "cannot activate in atmosphere" accessibility built in.

Minimum Range comes in 2 tiers on PU8p16 though so ti's not hard to explore:

• 5% of maximum range, so 186k miles x 20 = 3,720 k miles (3.72 million miles) true max
• 1% of max range, so 186k miles x 100 = 18.6 million miles

This actually mentions "for sensors with a “blind spot” within which they can’t resolve targets" implying that you can take Minimum Range on Detect, and due to that, it must have a max!

This probably means 100 yards (buying increased range for more) but could apply to the above, assuming one of the 2 types of MinRange are built into Hyperjump to generate the "unwritten max" of it for those who don't take Range Limit.

-50% is light-second per second while -25% is light-year per day. There are 86,400 seconds in a day, so that is the distance of a "light-day", which is then multiplied by 365 (days per year) to determine how many light seconds are in a year. That is 31,536,000, a factor of over thirty-one million between the distances being talked about. But since it takes an entire day to do that, you divide it by the rate of seconds per day to actually just get a x365 factor in speed difference.

Either 'takes extra time' or 'reduced time' might create a relationship between the two limitations as 'metamodifiers'. It being unclear which is baseline. Both appear to last indefinitely (keeping the person at high speed, hard to target) until reaching destination.

see also

• Awareness
• Sense-Based (Reversed)