GURPSよろず

　When modifying advantages to represent spells, the following limitations are useful.
Anyone observing gestures or words will automatically realize that you’re casting a spell if he has any familiarity with magic.
Someone with actual magical training (even if only theoretical, such as Occultism or Thaumatology) may roll vs. an applicable skill (or IQ) as a free action to identify what the spell will do.
This roll is at -4 if you are only speaking or gesturing, or at no penalty if you’re doing both.

　Your hands – and to a lesser degree, the rest of your body – must be free to move about.
If your arms are restrained in any way, or your lower body is fully pinned or clamped in place, you cannot use your ability. -10%.

　You must chant at normal conversation levels. You cannot be gagged, and stealth is impossible. -10%.

　You must have something specific in your hand (or with your hand resting on it, for large things). It needs to be defined with some specificity: “a rock” is too broad, but “an agate” is fine. (Extremely rare needs may be worth an extra -5%, if the GM is feeling generous.) Unlike Trigger (p. B115), the component is not used up. -10%.

　Some supernatural abilities are powered by a ritual that must be performed on a regular basis, instead of every time the spell is used.
If not, the ability shuts down until you can invoke the ritual.
Decide if it’s required once per day or once per session; either way, the following values are fair.

　It merely calls for 1d minutes of quiet chanting, and simple materials weighing no more than a pound. -5%.

　It involves cumbersome preparation and materials (lots of loud chanting, several candles, a bonfire, a complicated circle drawn on the floor, etc.), or a successful casting of a relevant spell at minimum FP cost, taking 1d×5 minutes either way. -10%.

　It’s something entailing 1d/2 hours of work, serious expense, actively illegal or somewhat dangerous behavior, or some combination thereof. -20%.

　Only on those who share a language with me: This commonly accompanies Hearing-Based (Sense-Based, p. B109) on mental-influence abilities. -10%.

　Only while moving: Abilities that let the user defy gravity – Clinging, Walk on Air, Walk on Liquid, etc. – often have this.
In a sci-fi game, pair it with Requires Low Gravity (p. 17). It’s incompatible with All-Out (p. 11). If the user stops moving, he falls.
This is worth -10% if he must take at least a step per second, -20% if he must travel at half Move, or -30% if he must use his full Move.

　Only while succumbing to (disadvantage with self-control roll): The ability is available only while the user is giving into his disadvantage, whether voluntarily or because he failed a self-control roll.
The size of the limitation is equal to the unmodified size of the disadvantage, as a percentage; e.g., “Only while succumbing to Gluttony” would be -5%, regardless of the self-control roll chosen.
See Only When Berserk (p. 16) for a special case and Required Disadvantages (p. 16) for disadvantages that lack self-control numbers.

　Only while using (ability): This ability turns on only when a different ability is in use. For this to be a valid limitation, both abilities must be useful on their own and neither can have a Link (p. B106) to the other. -10%.

　Only with assistants: Some supernatural abilities require ritual or worship by others to work. Halve the basic point value that Maintenance (p. B143) gives for that number of people and write it as a percentage; e.g., “11-20 people” is -25%.

　Requires (item): This variant of “Requires material component” (above) suits abilities that seem like they should use gadget limitations (pp. B116-117) but actually work with any piece of appropriate mundane equipment. For example, a super-archer with a special, custom bow would buy his Innate Attack with gadget limitations. However, one who can pick up any bow and make unrealistic shots would use Accessibility, Requires bow; if his bow is stolen or damaged, he can just run into a sporting goods shop and grab another. -10%.

　While conscious: Your ability requires a Concentrate maneuver (never a Ready or a free action) to activate, and it switches off immediately if you lose consciousness.
Use this with switchable abilities, but not with transient ones (including most attacks), as those automatically shut down after the turn in which you use them. -5%.