(Sorry to the OP, who doesn’t want to use magic But that may help see the overall check mechanisms based on these skills.)
Thanks! For Trickery it’s pretty clear. And I understand UMD is actually another check.
I found several bits of info in the rulebook, it looks as if UMD is only necessary for classes that can’t cast spells and want to use a spell scroll or a magic wand. This would mean that
- Use Magic Device is not necessary for spell casters (if the spell is in their domain),
- Spellcraft is not necessary for other classes than spell casters.
The core rulebook explains this poorly as usual, so I may be wrong. And unfortunately they didn’t detail the scroll checks in either game of Pathfinder, so it’s not obvious to validate.
Here’s what I understood:
1 - Casting a scroll spell
a) With the spell ability or a caster class, casting a spell from a scroll include several steps
- decipher the scroll: spellcraft check, DC 20 + spell level vs Spellcraft (INT)
- activate the spell: provided the conditions are met: correct arcane/divine type, spell on class list, ability score high enough,
- if the caster level >= spell level, activation without check
- otherwise, caster level check: DC 1 + spell level vs Spellcraft (INT) (I think), and if that fails, a DC 5 vs WIS to avoid a scroll mishap (unwanted effect) and the destruction of the scroll.
- effect: other checks such as spell resistance, saving throws and so on, depending on the spell. Those checks are normally performed by the targets.
If I understand correctly, the ability score is based on INT for wizard spells, WIS for divine spells, CHA for sorcerer and bard spells. It must be >= 10 + spell level.
b) Without the spell ability or a caster class, Use Magic Device (CHA) must be > 0, and
- decipher the scroll: DC 25 + spell level vs Use Magic Device
- emulate the ability score: the ability score used is INT for wizard spells, WIS for divine spells, CHA for sorcerer and bard spells,
- if the ability score >= 10 + spell level, it is fine
- if the ability score is not high enough, DC = 15 + spell level vs Use Magic Device
2 - Using a wand
Using a wand is easier,
a) If casting class: the caster must identify the spell and that’s all. This is a DC 15 + spell level vs Spellcraft (INT)
b) In other cases, Use Magic Device (CHA) must be > 0, and the caster must pass a DC 20 vs Use Magic Device
Am I the only one thinking this is overdone? I’m not even venturing into the Scribe Scroll action, for which I’m pretty sure most games including Pathfinder just bypass some of the checks.