Powerstone Program
 

The Powerstone formula in GURPS Magic seems very sensible and there is a handy chart giving the typical price for many powerstones. But still, doing the formula for several stones with capacities that don't match the ones in the table takes time and, if you're like me, can involve mistakes.

I admit I only did a cursory search, but does anyone know an online or downloadable program for figuring typical powerstone costs? I'm thinking of something where you type in the capacity and it spits out a price. I could write such a program myself (it would be very basic), but if I’m too lazy to use the formula….

Re: Powerstone Program
 

I turned it into an Excel spreadsheet a while back.

Re: Powerstone Program
 

Try making a favorite/bookmark out of the following as the address, then load the favorite/bookmark. It should ask you for a powerstone capacity, then bring up the answer on google.

Re: Powerstone Program
 

Thanks for the suggestions. Ironically, shortly after I asked the question I thought of another way to do it, although this might be a bit more work than your suggestions.


Save the equation for the powerstone cost in a word processing program: ((10 * P^2 + 40 * P)/(53/54)^P) + (20 * P)

Replace All the P's with the capacity (for a 100 point powerstone P = 100; 157 point powerstone P = 157)

Then copy and paste it into an online scientific calculator such as found at http://www.ecalc.com/


To learn the cost of an unenchanted "stone" that would work efficiently to be enchanted to P capacity, do the same thing with

10 * P^2 + (40 * P)

Re: Powerstone Program
 

RPK hosts a spreadsheet on his MyGURPS site that covers both powerstones and other enchantments. It's designed to stay close to RAW while allowing the user to vary the base assumptions to personal taste.

Edit: Oops. Forget I said anything; it doesn't seem to be there. Will post again if I figure out where it is. AH, here we go:


http://www.mygurps.com/pics/Pstone_rev2010.xls

Re: Powerstone Program
 

I love bookmarklets. This is a very clever and marvelously portable solution!

Re: Powerstone Program
 

Thanks for the link! It looks useful for other things as well.

Re: Powerstone Program
 

The powerstone formula in vanilla GURPS is actually somewhat problematic because it makes no attempt to address the issue of quirks; the spreadsheet mentioned above seems to make some attempts at fixing the issues, though I have quibbles with details (notably, he leaves out the entire issue of powerstones created with cheap materials, and they actually matter a lot. I did some of my own analysis here).

Re: Powerstone Program
 

True, that. I originally did the spreadsheet for 3e, and just never got around to redoing it to account for the cheap material rule. Maybe someday...

Re: Powerstone Program
 

It's an oddly different problem, because you don't have to decide beforehand how big of a stone you want. Thus, if it quirks, you might simply stop enchanting the item, because spending labor on something already flawed has lower value than spending labor on something unflawed. This depends a bit; enchantment-grade powerstones generally want to be specific sizes, so you probably can't sell a 30 point stone for much more than a 24 point stone (suitable for 200 energy enchantments), you may be better off pushing up to 32 (suitable for 250 energy enchantments).

Incidentally, humorous (due to complete wrongness) quote from 4e: