What are the best magical systems in GURPS?

[Rupert]

Originally Posted by AlexanderHowl

Realm magic without FP is an option, but Realm magic is really expensive from a CP point of view even without a FP cost (its effects are still limited by the level of the effect, as is the casting time). I am not sure that, with 400 CP of IQ and magical traits, what would happen if a Realm magic w/o FP went up against a RPM mage. Heck, I am not sure what would happen if they went up against a standard mage.

Let us examine a standard mage with 400 CP in IQ and magical traits. They purchase IQ 20, Luck, Magery 3, and Magical Resistance 10 (Improved, +150%), for a total of 300 CP, leaving them with 100 CP for other magical traits. At that point, they are capable of mastering several colleges without major effort and, because of their high base skill, they can reduce spell cost by 2 FP per casting. With their Magical Resistance, they are also immune to the majority of spells, meaning that anyone who attempts to attack them directly with magic suffers a -10 penalty to skill. While a RPM mage will have better buffs and have conditional rituals, charms, and/or potions, it would really be difficult to say which mage would be better. I think that both would be better than the Realm mage (even w/o FP), just because the Realm mage must spend so many points purchasing the Realms.

I don't think the Magic Resistance is a very useful thing to put in as part of the 'mage build'. Anyone could have it, not just mages, and it doesn't make a mage better at magic. Also, if a standard mage should have it in their 400CP budget, so should all the other types of mage. At that point all the mages are working costings on each other at -10, and resisting at +10, and the mage that can best cast spells that don't directly attack the opponent (and thus don't take the penalty and avoid the resistance check) will be the winner. With any sort of prep that's quite possibly the RPM mage, though a standard mage that bought a large ally group (for ceremonial castings) and the right spells might compete.

Also, unless you're confident you'll never need magical help from outside yourself you'll want that Magic Resistance to be Switchable (+10%) - it only costs 2 points, so why not?

[Taneli]

I'm considering having a variant of RPM in my next fantasy themed campaign, where:

• Instead of gathering for energy, you roll casting once, and you take a penalty to your casting skill equal to the final energy cost, divided by 10 and rounded down.
• Spells have a standard casting time and greater effects increase this.
• You can only improvise cantrips (spells that have an energy cost of less than 10) on the fly. Other spells must be learned from a source or invented using the invention rules**.
• To cast a spell you must either know it*, have a source available for it (essentially, a spellbook), or it is a cantrip you improvised.

* Learning a spell requires you to have a source for it that you can understand, and takes one full day of study, plus one day per greater effect that the spell has, and a skill roll for the correct path with a penalty equal to the spells nominal*** energy cost, divided by ten and rounded down, plus any penalties from bad translations, nonperfect language ability, slightly missing material, and so on, and any bonuses from good or excellent materials.

** This doesn't mean that spells are set in stone, you can still adjust spells effect for damage, range, duration, target, and so on, where applicable. So no turning a fireball spell into a fire storm spell, for instance.

*** Nominal energy cost refers to all the spells effects, but does not include cost for range, target, etc.

Oh, and spells can be improved as average techniques, or maybe as hard techniques for spells that have more than x greater effects, where I'm wondering on the value for x.

Oh, and Magery (This variant of RPM) adds to your skill with the paths.

I'm not yet sure on how to go with group magic, my current theory is that the helpers get to make relevant Path rolls to give a bonus to the main casters roll, but not sure.


Why?
This variant addresses my fears about standard RPM replacing everybody else and also winning all problems by just improvising a new spell. It also makes spell books more important than in the standard gurps magic, and removes something from the arbitrariness of the standard gurps magic by replacing the spell generation rules with the IMO better rules from RPM.

So yes, I think this might be the best magic system, but as I have not yet tested it, I don't know.

[johndallman]

Originally Posted by Taneli

• You can only improvise cantrips (spells that have an energy cost of less than 10) on the fly.

You might want to make the cap of 10 a function of Magery? That lets mighty magicians do more with improvisation than apprentices.

[johndallman]

[QUOTE=Taneli;2347551]

• Instead of gathering for energy, you roll casting once, and you take a penalty to your casting skill equal to the final energy cost, divided by 10 and rounded down.

Another idea: D&D-style fantasy magic systems are good for combat, but don't deal with the idea of slow ritual magic, requiring lots of props, aka "ceremonial" casting. There's a way to provide that with this RPM variant.

For ceremonial casting, you revert to gathering energy, with one gathering roll every five minutes (or even longer without Ritual Adept). This makes for long ceremonies, with plenty of time for enemies to interfere. It might even allow casting spells that aren't known or in an available source: this could be the equivalent of a prototype.