Spells as Powers - Weapon Enhancements and Other Problematic Spells

[N.H.Alicia]

I like statting spells as powers. It makes balancing much easier. Unfortunately, it makes certain spells much harder to stat, like weapon enchantments.

Say I have a sword. I want a power that can give the sword bonus damage and/or other bonuses - how would I create that power?

[weby]

Bonus damage is simply innate attack with suitable modifiers.

Example: Self spell: do 1d6 extra fire damage with any weapon:
Burning Attack 1 (Follow-Up, Any weapon, +50%)[7.5]

If you want to limit it to melee range then add melee modifier, if you want it to be a buff spell then make an afflict that applies it and so on.

Edit: The +50% for follow up any weapon is official, but in my own games as a house rule the +50% only buys melee OR ranged and to get both requires a +100%

Thus burning missiles in my sorcery implementation (https://hups.kivinen.iki.fi/k2011:sorcery) is:
burning missiles: afflict (burning missiles +22.5%, Sorcery -15%, malediction:+100%, accessibility:cast on weapon:-5%, touch:-30%)[19], extra levels up to 5, are +2 points each and do +1 damage. burning missiles is: 1 point of burn damage(1 point: x0.3 Universal ranged followup:+50%)[2.25]

[Kelly Pedersen]

Besides what weby said, which is definitely correct for adding damage, adding other effects (such as armor divisors, range to normally-melee attacks, and so forth) is covered, in GURPS Thaumatology: Sorcery, by converting various Imbuement skills (which are in turn from Power-Ups 1: Imbuements) into advantages.

In general, Sorcery seems to be doing what you want to do here (turn advantages into spells you can cast), so you should probably look at that for useful tips.

[Varyon]

Thaumatology: Sorcery, page 11, has the rules for building weapon enhancements as Powers (as Sorcery is Magic as Powers). An alternative I'm fond of is a bit more complicated.

Essentially, treat the character as though he/she had the weapon as an appropriately-modified Innate Attack (for self-powered weapons) or Natural Weapon (for muscle-powered ones). You then simply add the appropriate Enhancements and work out what their costs would be - for a Crushing weapon, every +20% (or fraction thereof) is [1], for example, while for an Impaling weapon every +12.5% is [1]. You then build an Affliction to cast it on the weapon. For abilities that can work on multiple types of weapons, build it for the most expensive and multiply cost by 1.2 (I feel it's roughly worth two equal powers built as Alternate Abilities, hence the pricing). If it can work on both ranged and melee, I'd bump that to a multiplier of 1.5.

Note here you don't need to work out the modifiers for the original weapon, as modifiers only care about the base cost (unless using Multiplicative Modifiers, in which case the above scheme is probably too complicated to try to use). It can still be useful to work out some of them, however, as some enhancements will actually be buying off Limitations or or upgrading Enhancements. For example, a spell that makes a weapon indestructible would give it Resilient +40%. Very Fine weapons already have Resilient +20%, Fine have Resilient +10%, and Cheap have Fragile -20%. Thus, that's actually only +20% for Very Fine weapons, +30% for Fine, +40% for Good, and +60% for Cheap. I use the same methodology for my own take on Imbuements.

[weby]

I do not use imbuements for weapon buffs, instead for the armor divisors and the like I use the same procedure as Powers 146 for modifying ST based damage.

The resulting spells are then limited in how much force they can affect.

[N.H.Alicia]

This thread has been a huge help.

The second question was going to be how to model mages with large numbers of spells, but buying them as alternate abilities should work - Sorcery is damn good!

[weby]

Originally Posted by N.H.Alicia

This thread has been a huge help.

The second question was going to be how to model mages with large numbers of spells, but buying them as alternate abilities should work - Sorcery is damn good!

Not that also modular abilities are a possible way to allow a lot of spells for a mage.

[rkbrown419]

Originally Posted by weby

Not that also modular abilities are a possible way to allow a lot of spells for a mage.

Sorcerous Empowerment is a modular ability.

[weby]

Originally Posted by rkbrown419

Sorcerous Empowerment is a modular ability.

Yes, but an expensive one that only allows 1 point for each level with levels costing 20/10. If you are going for modular abilities only so simulate something like a D&D mage you would likely use cheaper slots with things like Takes Extra Time added instead of reduced time.

[N.H.Alicia]

Originally Posted by rkbrown419

Sorcerous Empowerment is a modular ability.

Buying spells as alternate abilities of Sorcery is cheaper - the modular component is mainly for improvised spells.