There are three main forms of casting spells under the Hermetic Code. They Formulaic Magic, Spontaneous Magic, and Ritual Magic.
Casting Score = Technique + Form + Aura Modifier
Formulaic Magic Casting spells which the Magi already know. Having studied under another, read in a tome, or experimented in laboratory, the Magi has practiced and learnt the means for performing this spell.
(Casting Score + Die Roll) = Casting Total
Casting Total equal to or higher then Level = Success, no loss of fatigue
Casting Total miss by 10 or less = Success, loss of 1 fatigue
Casting Total miss by 11 or more = Failure, loss of 1 fatigue
Spontaneous Magic Using Technique and Form to create magical effect without need of known spell.
The magi chooses to Exert oneself or not
Exerting is Fatiguing (-1) but…
(Casting Score + Stress Die)/2
Not Exerting is Non-fatiguing but…
Ritual Magic known spell which require elaborate rituals and raw vis. A Magi prepares for undertaking these spells for raw vis is consumed and the world is often forever changed by these spells. It is common for Magi to read the stars and alinements before performing these spells on specific days at specific times.
15 minutes of ritual per magnitude of spell (1 magnitude per 5 levels)
1 pawn vis is spent per magnitude
Casting Total = (Casting Score + Arte Libeerales + Philosophiae + Die Roll)
Casting Total equal or higher then level = Success, loss of 1 fatigue
Casting Total miss by 5 or less = Success, loss of 2 fatigue
Casting Total miss by 6-10 = Success, loss of 3 fatigue
Casting Total miss by 11-15 = Failure, loss of 4 fatigue
Casting Total miss by 16 or more = failure, loss of 5 fatigue