How does Power affect cost for a Magic Item?

[Icelander]

I did not find a note to that effect in either GURPS Magic, GURPS Thaumatology or GURPS Dungeon Fantasy: Adventurers.

GURPS Magic 3e had a rule which increased cost by 20% for Power 16, +40% for Power 17, +60% for Power 18, +100% for Power 19 and then another +100% for every +1 to Power.

The fact that this rule does not appear in 4e might suggest that it is invalidated, but I've been taught not to leap to conclusions of expressio unius est exclusio alterius.

Personally, though, I think that a Power 20 item is rarely (though not 'never') three times as useful as a Power 15 item. So I find the cost increase a bit steep. Especially since it does not take into account the availability of magic in the setting and the specific assumptions made for enchantments.

In my setting, for example, skill 20 wizards are relatively commonplace and skill 25+ wizards do exist. I allow the use of Time Spent rules with Slow and Sure enchantments and I also allow wizards to contribute man-days at the rate of their Magery per day.

Few, if any, of high Power item are created by skill 15 enchanters pouring extra Fatigue Points into their enchantment. Most are instead made by skill 20-25 enchanters who simply don't bother to take a penalty to skill to create the item faster.

Does anyone have any official guidelines for how high Power should affect cost based on the individual assumptions of the campaign?

[Fred Brackin]

Originally Posted by Icelander

I did not find a note to that effect in either GURPS Magic, GURPS Thaumatology or GURPS Dungeon Fantasy: Adventurers.

GURPS Magic 3e had a rule which increased cost by 20% for Power 16, +40% for Power 17, +60% for Power 18, +100% for Power 19 and then another +100% for every +1 to Power.

4e still has the basis for this rule in the Ceremonial Magic section where extra energy equals more skill. I suspect that the extra cost for Power-20 items was either left out to make room for the longer (but not very useful) discussion about the economics of Enchantment or deliberately left out becasue it's a setting specific detail (like people using Powerstones in Enchantment alledgedly is).

It's always been somewhat problematic. That I've ever been able to tell there is no minus to S&S as there is for Q&D so the Power of S&S items should always be the (highest) Skill of the Enchanter(s).

So for items produced by lone hermits Skill 20+ should probably be the norm. Especially if you factor in On the Job Training to Enchanting.

Then you consider settings where there is little Low Mana around plus the way the Rule of 16 affects items containing Resisted Spells and high Power isn't always that useful.

With all of this and other things to consider and I'm afraid the answer might be "You're on your own.".

[Kuroshima]

Originally Posted by Icelander

I did not find a note to that effect in either GURPS Magic, GURPS Thaumatology or GURPS Dungeon Fantasy: Adventurers.

GURPS Magic 3e had a rule which increased cost by 20% for Power 16, +40% for Power 17, +60% for Power 18, +100% for Power 19 and then another +100% for every +1 to Power.

The fact that this rule does not appear in 4e might suggest that it is invalidated, but I've been taught not to leap to conclusions of expressio unius est exclusio alterius.

Such rule is still in 4th ed, in DF4 - Sages (though it is presented only for scrolls), so no, it has not been invalidated. Oh, and power higher than 15, by the standard rules, are both a big time investment (you have to do the enchantment with less assistants than you idealy could, leading to the enchantment requiring a lot more time, and decreasing the threshold where Q&D is possible) and have only niche uses (The work in low mana zones, and resisted spells cast by such items have a little longer range)