Copyright (c) 2009 Kyrinn S. Eis
This has been simmering for a few weeks:
The exact Spell Magnitude number must be rolled on a die, with the number of dice equal to the number of Spell Points possessed and available, plus 01.
If the required number is the die result, that Magnitude of spell may be freely cast without the expenditure of the Spell Points.
If, instead, any other number is rolled, the warp and woof of reality did not support the harvested energy within the Kherstic matrix, and requires the expenditure of the listed SP if the spell is to be successfully cast.
If the figure has insufficient SP to cast a spell, DP may be substituted at a 1:1 ratio.
1-3 : d4
4-5 : d6
6-7 : d8
8-9 : d10
:: Eshylzbet seeks to cast the spell, Xhillsen Del Hamn 'Being a powerful working of the air into a duty-bound being; a being of subtle spirit from above; a servant of the Empyrean.' This spell is 4th-Magnitude, and costs 04 SP. At present, Eshylzbet has only 03 SP, and attempts to empower the Kherst matrix with ambient energy instead.
:: Her player rolls 4d6 (because 4 Mag must be rolled on the next-higher die-type than d4, which is d6; the number of dice is derived from the current number of SP she has available, plus 01): 1, 2, 3, 5 -- no success. For Eshylzbet to cast the spell, she must expend all three of her SP, and sustain a loss of 01 DP to make up for the deficit of 01 point.
However, crafting magic items, including single-use items such as scrolls, require too great a degree of focus to allow for the gathering of ambient Aether, and subsequently necessitates the expenditure of personal SP (etc.) reserves (although the SP/DP need not be given willingly...).