Spell resistance

[xalien]

I'm curious what is the formula for spell resistance?

E.g. Domination has 10% chance to be resisted. What happens if the caster has tower of alteration (-20% to enemy resistance) and archmage has metamagic 3 - as far as I understand it modifies targets resistance by -5% for each level. Do I get 94.5% chance to dominate target now?

 

[xienwolf]

Add all modifiers to get chance to resist. Base is 20, min is 5. Max is full 100

So for Your example

Base Resist (20)
Spell Base (+10 = 30)
Archmage Bonus (-5*3 = 15)
Tower Bonus (-20 = -5)
fix to Minimum (5)

So a 5% chance to resist

 

[xalien]

Ahh, didn't know about base 20 and min 5. Guess I'll save this spell for more interesting targets then.