[Basic] Advantage of the Week: Invisibility

[johndallman]

Invisibility [40] is an exotic advantage that may be physical or mental. You are invisible all the time, unless you take an enhancement to change that, but can still be detected via other senses. This advantage first appeared in GURPS Supers for 3e, and several variations were collected into the 4e trait.

The usual kind of invisibility affects electromagnetic radiation, from Ultravision to radar. That means you don’t cast a shadow, and don’t show up in mirrors. Other kinds of “vision” include sonar, magnetic, and anything else that exists in the setting. Powers has examples, including submarines that are invisible to sonar and magnetic vision. Paranormal (magical, psionic, etc.) kinds of remote viewing won’t see you if their users could not see you with their ordinary vision. Non-visual paranormal detection abilities, for enemies, life, and so on will work on you. Machines can see you, by default.

While invisible, you still leave footmarks, make noise, and have a scent. Anything you carry remains visible, by default, but you can buy the Can Carry Objects enhancement, which is priced by encumbrance level, from +10% for No Encumbrance to +100% for Heavy. If everything you’re carrying is invisible, you get +9 to visual Stealth.

Other enhancements include Affects Machines, whose usefulness varies widely by TL; invisibility to more than one kind of vision; Switchable and “Usually On” where it costs 1FP/second to be visible. Limitations include Machines Only, where living beings can see you normally, Substantial Only, where insubstantial being can see you, and having a visible reflection or shadow. Powers adds the limitations of a faint outline or shimmer, “Fringe, -10%,” and Glamour, which allows a Will roll to resist, with a discount varying by the Will penalty.

Invisibility shows up on templates for spirits and the like, plus magical monsters, far more than as a stand-alone trait. Discworld adds “Only while Insubstantial, -10%” for those who also have Insubstantial, and DF19 makes it clear that in DF, unlike normal GURPS, hostile actions end Invisibility, at least briefly. Horror expands on “kinds of vision” and MH6 Holy Hunters adds “Only on the astral plane, -30%.” PU4 Enhancements points out the usefulness of Selective Effect, and Powers: The Weird has “Only to 3-dimensional beings, -10%.” Reign of Steel: Will to Live has the rules for locating things that have Invisibility (Sonar, Sonar-Absorbent -10%), Supers has an Invisibility Suit and Ultra-Tech has Invisibility devices with more technological plausibility.

This is an advantage I’ve used a lot. In the occult WWII campaign, I’ve been playing a character with Invisibility since 2007. Keeping the opposition from realising what was going on was a priority from the beginning, involving a lot of points in Stealth, a couple of levels of Silence, and a lot of care about tactics. The character always had Switchable, Substantial Only, and Can Carry Objects (Medium Encumbrance), and the Mana Sensitive PM, which made an effective power. Improvements in play added Cosmic (Invisible to See Invisible (Magical)), Low Magical Signature (based on Low Psi Signature, from Psionic Powers), Not Substantial Only, and Selectivity. Sneakers, for the +1 to Stealth, and a really good knife are very helpful; Night Vision makes the sneak-up-and-stab method far more reliable.

What have you done with Invisibility?

[RogerBW]

I particularly recall the moment when that invisible character of John's picked up a lit lamp, and I suddenly had to make use of my conception of how the underlying power worked to determine what would happen.

I think that one does need such an underlying conception. There are many approaches to invisibility even without taking insubstantiality into account, and they're all modelled by the same GURPS power – most obviously, what one might describe as really good transparency, or really good camouflage, or mind-control powers so that one isn't noticed…

I've made quite a bit of use of the Visibility section of p. B394 when adjudicating situations with invisible combatants.

[ravenfish]

I'd like to see an official limitation value for invisibility that fails on attacking or otherwise dramatically drawing attention to oneself a la dungeon fantasy (or, if we believe this to happen by default at no cost change in Dungeon Fantasy, an enhancement value for violence-stable invisibility, which is by no means unprecedented in the genre).

[Crystalline_Entity]

I've an partially-irrational aversion to this advantage on cost grounds.

Obscure 10 (Vision; Defensive, +50%; Stealthy, +100%; Extended, Infra-Red, +20%; Extended, Radar, +20%; Extended, Ultraviolet, +20%) [62] is cheaper than Invisibility (Affects Machines, +50%; Can Carry Objects, Heavy, +100%) [100] but appears to me to have a similar game-mechanical effect. I could be missing something, but I'm not sure why you'd buy Invisibility over Obscure.

[WingedKagouti]

Originally Posted by Crystalline_Entity

I've an partially-irrational aversion to this advantage on cost grounds.

Obscure 10 (Vision; Defensive, +50%; Stealthy, +100%; Extended, Infra-Red, +20%; Extended, Radar, +20%; Extended, Ultraviolet, +20%) [62] is cheaper than Invisibility (Affects Machines, +50%; Can Carry Objects, Heavy, +100%) [100] but appears to me to have a similar game-mechanical effect. I could be missing something, but I'm not sure why you'd buy Invisibility over Obscure.

You can detect if something is Obscured, but with the Stealthy modifier you just can't determine an accurate location, size or shape. With Invisibility you don't detect anything.

[Say, it isn't that bad!]

Originally Posted by WingedKagouti

You can detect if something is Obscured, but with the Stealthy modifier you just can't determine an accurate location, size or shape. With Invisibility you don't detect anything.

"Vague humanoid-ish blob" versus "Can't see anyone, cap'n."

[Not another shrubbery]

Originally Posted by WingedKagouti

You can detect if something is Obscured, but with the Stealthy modifier you just can't determine an accurate location, size or shape. With Invisibility you don't detect anything.

Yeh. He forgot to account for switchability and the Area Effect, two more advantages of Obscure. Radar is not a valid Extension of vision for Obscure. It is a Scanning Sense (Powers, p64).

[Crystalline_Entity]

Ah, okay, so they're not identical if Obscure still lets you see if there's something there, just not what. I think I misunderstood what Stealthy did.

I'd actually assumed Scanning Sense (Radar) was opposed by the Extended (Microwave) enhancement, as it was listed on B72 alongside Infravision as a blockable sensory advantage, and then Infravision was specifically noted as valid for the Extended enhancement for Obscure (Vision), but it's not listed on P64 under vision.

And I did indeed forget Area Effect and Switchable in my comparison, sorry, it should be Invisibility (Affects Machines, +50%; Area Effect 1 (2-yard radius), +50%; Can Carry Objects, Heavy, +100%; Switchable, +10%) [124].

[WingedKagouti]

Originally Posted by Crystalline_Entity

Ah, okay, so they're not identical if Obscure still lets you see if there's something there, just not what. I think I misunderstood what Stealthy did.

I made the same mistake when I first read it, but all Stealthy actually does is:

Originally Posted by B72

There is no bonus to detect the boundaries of your area of effect

[Daigoro]

Originally Posted by Not another shrubbery

Radar is not a valid Extension of vision for Obscure. It is a Scanning Sense (Powers, p64).

Why would that be different than someone with a torchlight?

And I'm not sure how 10 levels of Obscure + Stealthy wouldn't be the same as Invisibility- it's often treated as the same in other discussion on the forum.