I am assuming T:ETP here. This is the way I am running spell casting in my campaign, and the players have had no problems with it, yet....

Quickly, generating a Spell Casting Check goes like this: [Base skill - Level of Spell/3, round up - Spell Cost/15, round up - other mods as appropriate (Temple spell, &c.)].

Spell Casting Cost is the same as the purchase price paid for the spell during character creation: [(Base spell level - Defects) x {2 + (number of Attributes + number of Specializations)}]. This is the number of Energy Points spent to attempt to cast the spell, successful or not.

First example: Basic Healing, Level 3 Spell, Casting Cost 6 [3 (base spell level - Defects) x 2 + (number of Attributes + number of Specializations)], no other modifiers. This is also the formula for purchasing Spells. If one has a Skill Level of 3 in Ritual Magic, a DEX of 7 and a PSY of 8, the base skill check is 11 [3 + (7 + 8)/2]. To successfully cast the Healing spell, base level, would require a skill check against a 9 [11 - (3/3) - (6/15)]. 

Second example: Greater Healing Level 3 Spell, Casting Cost 30(!) [3 (base spell level - Defects) x 2 + (number of Attributes {6} + number of Specialization {2})], or [3 x (2 + 6 + 2)]. Remember that higher level Attributes and Specializations require the inclusion of prerequisites into the spell calculation. The same caster as above, 11 Ritual skill, would have a successful casting on an 8 or less [11 - (3/3) - (30/15)].

Third example: Basic Necrofracture Level 10 Temple Spell, Casting Cost 20 [10 (base spell level - Defects) x 2 + (number of Attributes + number of Specializations)], or [10 x (2 + 0 + 0)]. Our skill level 11 caster would have a skill check of 3(!) [11 - (10/3) - (20/15) - 2], or [11 - 4 - 2 - 2]. 10/3 is the spell level modifier, 20/15 is the casting cost modifier, and the last 2 is the Temple penalty.

Fourth example: Spell Casting Shedra Necrofracture Level 10 Temple Spell, Casting Cost 40(!) [10 (BSL) x 2 + (number of Attributes + number of Specializations {2})], or [10 x (2 + 0 + 2)]. Our skill level caster would have a  skill check of 2(!) [11 - (10/3) - (40/15) - 2], or [11 - 4 - 3 - 2]. Again, the 10/3 is the spell level modifier, 40/15 is the casting cost modifier, and the last 2 is the Temple penalty.

None of these take into account environmental factors, such as noise, combat, &c., which could drive the check even lower.

The reason for both mods is to make all casting of higher potency spells more difficult for the low-end caster. While the first mod is fixed for the level of the spell, the second mod continues to increase as more Specializations and Attributes, and therefore "Other-Planar Energies", are added to the spell.

I hope this is useful, and not overly confusing. I tried to give the most basic and extreme examples I could think of. If more clarification is needed, just holler.

Chris

On Fri, Oct 10, 2008 at 11:34 AM, allanprewett2000 <eworlds@bigpond.net.au> wrote:

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You may play with any word you like...it's the rules! - Pilz-E