Formulas and Game Mechanics

Spellcasting

It should be noted that the casting focus referred to in the discussion below is not the skill, Focus.

Chance to Cast

The following information is gathered from UO Developer Wilki's statements on the Stratics message boards.

• Chance to Cast = ( ( Skill - ( Difficulty - ( Casting Focus / 2 ) ) ) / Casting Focus )%
• Chance to Cast can never be negative, nor over 100%.
• The Minimum Skill Requirement to cast a spell exists two ways:
  • For Chivalry, Magery, and Necromancy: MinimumRequirement = ( Difficulty - ( Casting Focus / 2 ) )
  • For Bushido, Ninjitsu, and Spellweaving: MinimumRequirement = ( ( Difficulty - ( Casting Focus / 2) ) + ( ( Casting Focus * 5 ) / 20 ) )

Definitions

• Skill: The caster's skill level.
• Casting Focus: A predetermined value that defines how wide the "window" is between 0-100%, centered on the difficulty value.
• Difficulty: the point where you have 50% to succeed.
• Minimum Requirement: Minimum skill level required before spell can be cast (even if the chance to cast is above 0).

Values

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Casting Focus

• All Bushido: 50
• All Chivalry: 50
• All Magery: 40
• All Necromancy: 40
• All Ninjitsu: 50
• All Spellweaving: 50

Difficulty

Bushido

• Honorable Execution: 37.5
• Counter Attack: 52.5
• Lightning Strike: 52.5
• Confidence: 37.5
• Evasion: 72.5
• Momentum Strike: 82.5

Chivalry

• Cleanse by Fire: 30
• Close Wounds: 25
• Consecrate Weapon: 40
• Dispel Evil: 60
• Divine Fury: 50
• Enemy of One: 70
• Holy Light: 80
• Noble Sacrifice: 90
• Remove Curse: 30
• Sacred Journey: 40

Magery

• 1st Circle: 0
• 2nd Circle: 15
• 3rd Circle: 29
• 4th Circle: 43
• 5th Circle: 58
• 6th Circle: 72
• 7th Circle: 86
• 8th Circle: 100

Necromancy

• Curse Weapon:
• Blood Oath:
• Corpse Skin:
• Evil Omen:
• Pain Spike:
• Wraith Form:
• Mind Rot:
• Summon Familiar:
• Animate Dead:
• Horrific Beast:
• Poison Strike:
• Wither:
• Strangle:
• Lich Form:
• Exorcism:
• Vengeful Spirit:
• Vampiric Embrace:

Ninjitsu

• Animal Form
  • Rabbit & Rat Form:
  • Cat & Dog Form:
  • Giant Serpent Form:
  • Bullfrog Form:
  • Ostard & Llama Form:
  • Wolf & Bake Kitsune Form:
  • Unicorn Form:
  • Ki Rin Form:
• Backstab:
• Surprise Attack:
• Mirror Image:
• Shadow Jump:
• Focus Attack:
• Ki Attack:
• Death Strike:

"Plain English" Version

• Magery and Necromancy spells require 20 skill points above the minimum requirement to be cast 50% of the time, and 40 skill points above the minimum requirement to be cast 100% of the time.
• Chivlary spells requires 25 skill points above the minimum requirement to be cast 50% of the time, and 40 skill points above the minimum requirement to be cast 100% of the time.
• Bushido, Ninjitsu, and Spellweaving spells require 12.5 skill points above the minimum requirement to be cast 50% of the time, and 37.5 skill spoints above the minimum requirement to be cast 100% of the time.
• All minimum requirements except for magery are listed in game. Magery minimum requirements can be found on UO.com: http://guide.uo.com/magic.html