When I add a GetRandomPercent condition to a Concentration-type magic effect like the one for Sparks/Flames/Frostbite, how often does the game roll the dice for the condition when the spell is being cast? Does anyone know? Just for the hell of it, I removed the "ActorValuePercent Health" from Sparks' magic effect, and replaced it with GetRandomPercent <= 90. In theory this should make the spell apply the disintegration effect 90% of the time, but in practice it happens very, very rarely. This leads me to believe that the dice are being rolled not continuously as the spell is applied, but with significant delays between each roll.

Can anyone shed some light on this?

Once Per Second!

That is the reason the conditions svck EGGS for combat modding!

Really? I must be really unlucky then. Because I wouldn't see a side effect happen even if I kept the spell up for 10-20 seconds. 10-20 rolls and all are over 90? Odd....

spookyfx.com is correct about the once per second, but that is only if the condition is placed on the spell and NOT the magic effect.

If the condition is placed on the Magic Effect, the condition is checked only once at cast time.

I suspect you changed the condition on the magic effect, since Sparks (The spell) has no conditions. The conditions are on the magic effect Disintegrate (PerkDisintegrateConcAimed), as such the roll is checked only once per cast.

Ah yes, you are correct, sorry. However my explanation was based on the OP's statement:

"but in practice it happens very, very rarely."

Had he said "never" I would have had a different answer.