Take Fire Breath for example, in vanilla it does 50, 70, 90 damage, and the CK shows magnitude to match those, and duration 0. I wanted it to deal the damage over time, so i set the duration to 10 secs, and magnitude to 40 (first word), but now i'm having a hard time figuring out how much damage it does. It deals 100 damage to a Draugr, but a Sabre Cat with 150hp dies from it, and it should deal 40 over 10 seconds? Also, does Destruction skill affect the damage done by shouts?

Alright, i tested in another save just now, and it dealt the same 100 damage to a Draugr and a Sabre Cat, but in another save it kills the Sabre Cat. Something got messed up there. Destruction does not seem to affect shout damage, but i still don't get why magnitude 40 with a 10 second duration deals 100 damage.

These are good questions, that I can't personally answer. You might, however, wish to see if a Draugr and Sabre Cat have certain additional weaknesses to fire, or magic of the sort- that might explain some deviation you might be seeing.

Is not Fire Breath a Shout rather than a Spell? I don't think they work the same way. I think to do damage per second you might need a concentration effect like Flames

I am not entirely sure how it works in Skyrim. I did look into Daggerfall in detail back in the day with spread sheets and stuff and Magnitude, Duration and Chance against magicka cost varied greatly with Spell school and the type of spell. I could not find any consistent underlying mechanic for all spells of all schools.

EG, In Skyrim, for some Illusion spells, Magnitude is the level of creature that can be affected while for Destruction it is usually hp damage.

It's probably doing 40 damage per second for 10 seconds, so would in theory do 400 damage. You would not see this if the victim has only 150 hp. But there are other settings such as Taper effect that can affect this, as would perks, resistance and so on. If it is a fixed 40 over 10 seconds (which I doubt), the taper could be doing the extra damage. If it is 40 per second for 10 seconds, the Taper could be reducing it. Perks and Destruction skill should not affect Shouts (I think) unless you mod them to be affected. Also, if targets "catch fire", they get extra burning damage for a short time.

Also, all creatures have a chance to Resist Magick, Fire etc and so do not always take full damage. Plus, you sure you don't have any mods that might change things like this?

When you test this, are you using the console and TCAI to toggle combat AI and then conjuring the creature with player.placeatme and then getav health before and after casting the spell?

I made a spell recently that will give you this data if you cast it on a creature (any creature, friend or foe, NPC or monster etc). I was surprised that Draugr have no Fire Weakness (they are 100% resistant to Poison, 50% to Frost). Spriggans have -33% Fire Resistance, which is basically Weakness to Fire, but sabre cats have no Fire Resistance.

I have not put it up yet as I am not sure whether to make three separate spells, Discern Abilities for NPCs, prey animals etc
Discern Predator Abilities for dangerous animals and Discern Monster Abilities for draugr, daedra etc (maybe I should start a thread, see what people think?)

At first it was going to be a free power, but you CAN actually get useful combat information, so for enemies maybe I should make it a spell that costs magicka to cast.

You can see some screen shots here if you're interested: It's useful for testing purposes.

http://www.flickr.com/photos/shadowblade001/10060213146/in/set-72157636130956995/lightbox/

~.~