thnk it's possible to make "homing spells"?
for example, take Alduin's storm call shout: would it be possible to have the meteors "home in" to the player, but still with a chance of missing? or no chance at all, so that they always hit?
let me rephrase that: rather than having actually a custom perk for perk reduction, couldn't I use "SpellHasKeyword" "customkeyword"? although apparently this solution promts a window where one has to choose the casting method (left, right, instant, voice)


I've been browsing the creation kit, and seen that all multi-rank perks are in fact multiple perks. why is the system designed like that, rather than having a single perk with multiple ranks?
examples: Recovery Perk, Spell cost reduction perks, Deep wounds perk

It's probably doable through scripts, through successive calls to TranslateTo. I do not know if there is a better way, did you check at all the projectile's properties to see if there is no built-in way inherited from Fallout?

Well, it makes sense: the only thing that ranks have in common is the perk's name. Everything else can differ between two stages: conditions, effects, scripting, etc. Should they have used distinct perk and perk's rank objects, the perk would have been empty with just the name and the list of ranks.

I understand.
would it be performance-intensive to make an area with a script like:
all units within that don't have the keyword "isUndead/IsVampire" take 1 point of damage every six seconds?

Well, depending on what you mean by "home in on", the vanilla Storm Call script actually has this functionality built right in. The lightning bolts dropped by Call Storm can be set to always strike a target, to have a chance to miss, or to always deliberately miss. That's just how the projectiles are aimed, though; if the target moved after the projectile was launched, it would still miss.

If you mean actual homing projectiles, it's possible to do with scripting but it's very difficult to get a smooth path with no halts. I use https://www.youtube.com/watch?v=vZtOkcjfw2oin some of my spells, a homing http://www.youtube.com/watch?v=NQ12ZtdsUag in another, and of course my Dwemer Drone mod uses a sort of http://www.youtube.com/watch?v=SqoNCD67yWU to follow the player and ensure it doesn't miss with its strikes. You can kind of see my progression in getting homing/seeking objects working well in these videos, but even my best one, the Drone, still gets a little twitchy when the target moves around. It's just not something the engine is designed to do, at all.

The only other method I've thought about that might make a convincing homing projectile would be to make a flying actor FlyTo the target and detonate, and make the actor look like a projectile. I haven't had time to actually experiment with that yet, though.

That sort of keyword filtering functionality is actually built into the CK via Magic Effect Conditions, though I'm unsure how to apply a specific effect every x seconds without using at least a bit of scripting.

You're question is too vague.
Applying the dot would be made through a cloak. Other mods use this on quite large distances, so I guess it is fine but I do not know how much it affects performances. Factors like the area's size and maybe how often actors leave and enter the zone probably matters.
After that, it all depends on how much targets have the dot running on them.
As usual: the only way to know is to test.

wow your spells!
but I think Alduin Storm call has a chance to miss, doesn't it? unlike storm call that ALWAYS hits.

so do you think that area script could be very intensive? we already know it exists if you go, as a living being, near the soul Cairn entrance

Yes, Alduin's fireballs miss. The built-in Call Storm script has a toggle specifically to make its projectiles miss on purpose.

Nah, an area script that only effects certain actors with certain keywords would be minimally intensive (unless it was running 10 times a second or something, and even that can be done if you're careful). I don't know about using a cloak spell to do it, I would just use a spell with an Area + a condition to restrict damage to the actors you're targeting to deal the damage, and a script attached to an activator or a scripted ability attached to an actor to fire it every x seconds.

what about making it more similar to the soul cairn entrance: continuos damage?