» Fri Jun 22, 2012 1:10 am
OK... to be more specific (now that I'm in Windows land), you create a perk (I personally created one perk per school, and inserted them low in the skill trees by editing Actor Value / [spell school] / Perk Tree) with whatever criteria you want to earn it.
In the 'Perk Entries' window, you add a new entry with the entry point of your choice (Mod Spell Magnitude / Duration / Cost, whatever), and set the function to 'Multipy 1+Actor Value Mult'. This will change the thing below to "Value *= 1+ [actor value] * [constant multiplier].
To turn the skill rank for Destruction into a + damage % effect, for instance, you would simply select 'Destruction' in the dropdown, and '0.01' as the constant multiplier.
In the Spell tab, add a new item and set the condition function to 'EPMagic_SpellHasSkill', use the first button past the dropdown to select 'Destruction' (in this case), the comparison as '==', and the value as '1.000'. This will make this perk effect only alter spells that have 'Destruction' as their skill.
When this perk is on your character, any spell effect (castable spell, equipment, etc) with 'Destruction' as it's skill will increase in damage by 1% for every level you have in Destruction. It also continually updates, so as your Destruction goes up, so does destruction damage. You can easily modify this to affect other properties of spells based on other skills as you wish, and add extra perk items with conditions to create 'tiered' increases. With more tweaking and work, you could probably tie the value to a calculated value somewhere generated by a quest or background script... lots of options here. ^^
Edit: For testing, you might want to create a few test perks, a few tester items, and a custom script on those items that adds the perk on equip and removes it on removal. ^^
Edit 2: For increasing Rune damage, you can add a condition below EPMagic_SpellHasSkill of 'HasKeyword' with 'MagicRune'.
Edit 3: For increasing damage of specific tier spells, you can use the same technique they use for the cost reducing perks: 'SpellHasCastingPerk' condition, with the relevent perk (i.e. for novice Destruction spells, the casting perk is 'DestructionNovice00', etc.)