Valuing New Spells
Working in mmy quest to build a magic system for artesia rpg using burning wheel gold, I need to set resource points cost for spells. In this system you have shaped forms and magic principles. Shaped forms are magical rotes with specific magical effect. Magical principles are wider "mega-spells" that allow you tu cast a lot of related effects (Ex: Curses). For this I using for inspiration the work of +Thor Olavsrud
and the Art magic in Magic burner. You can have unlimited shaped forms but only a number of magical principles equal to your perception exponent.
So i revised the resource points cost in BWG. There is no clear rule about how to put cost to new spells. Revising the cost in the spell list I calculate the average, min, max and standar deviation to have an idea about how much cost spells in BW. I got an average about 12 points, a min of 4 points, a max of 24 points and a standard deviation of 5 points (so in avarage spells range about 6 points to 18 points, so so).
Considering this, I think that a good rule to cost shaped formes could be a cost of 3x spell ob, so a spell of ob 3 will cost 9 points and a spell of ob 5 will cost 15 points. In the case of graduated spells (with ^) you can add 3 points to the final cost (so a ob 5^ spell will cost 3 x 5 + 3 = 18 points). Finally, in the case of a spell without a clear objetive the GM can assigna a cost between 8 ponts and 16 points based in the perception fo the power of the spell.
Magical principles need to cost a lot more because in practice youcan invent a lot of spell only knowing one of them. I think that is possible to ranke the magical principles in principles less powerful, powerful and extremely powerful. Less powerful principle will cost 25 points, the powerful principle will cost 50 points and extremely powerful will cost 75 points. (25,50 and 75 cost is a typical cost structures in burning wheel, isn't?
What do you think?