Make Fortify Health safe to use

[nerevar009]

Currently, when a Fortify Health effect expires, it simply subtracts its magnitude from your current health, which can kill you if your current health is less than the effect's magnitude. This causes many players to never use Fortify Health. Skyrim adresses this by leaving you with at least 1HP, but that's still dangerous as you could die from a poisoned arrow or something. I think there's a better way to do it.

When a Fortify Health effect expires, reduce HP by (current HP - HP when Fortify Health effect was applied). If there's another Fortify Health effect active use the HP from when that effect was applied so you don't end up with more HP after the effect ends. If the difference between current and initial HP is less than 0, subtract 0 HP. If it's more than the magnitude of the Fortify Health effect, subtract only the magnitude. To make longer lasting potions/spells and constant effect Fortify Health enchantments more useful, it should fortify both current and maximum health (like the MCP option) so you can heal yourself back up to the fortified maximum. If the player levels up with a Fortify Health effect active, the health gained should be added to each Fortify Health effect's initial HP variable. It would work like this:

potion/spell/on-use enchant:

hp = 100
fortify health 100
hp = 200
take 100 damage
hp = 100
fortify health effect expires
hp = 100

constant effect:

hp = 100
equip constant effect fortify health 25 ring
hp = 125
level up 5 times, gaining 25 hp
hp = 150
take 25 damage
hp = 125
heal 25 hp
hp = 150
unequip ring
hp = 125

There might be a balance issue with a constant effect Fortify Health enchantment where after taking damage, you can un/reequip the item to reapply the fortification. A fix would be to increase only your maximum health in that case. Also, for consistency, Fortify Magicka and Fatigue should also work this way.

[raven]

Or it could be converted (internally) to a scale factor which should result in consistent/predictable mechanics.

potion/spell/on-use enchant:

hp = 100
fortify health 100 -> health factor = hp + fh/hp = 2
hp = 200 -> 100 * 2
take 100 damage
hp = 100 -> 50 * 2
fortify health effect expires -> health factor = 1
hp = 50

constant effect:

hp = 100
equip constant effect fortify health 25 ring -> health factor = 1.25
hp = 125 -> 100 * 1.25
level up 5 times, gaining 25 hp -> health factor = 1.2
hp = 150 -> 125 * 1.2
take 25 damage -> 25 / 1.2 = 21
hp = 125 -> 104 * 1.2
heal 25 hp -> 25 / 1.2 = 21
hp = 150 -> 125 * 1.2
unequip ring -> health factor = 1
hp = 125 -> 125 * 1

[raven]

Actually the intermediate calculations can be skipped altogether.

When removing fortify health effect just scale current hp by:
hp = hp * (1 - fortify / hpmax)

For the first example:
hp = 100 * (1 - 100 / 200) = 50

Second example:
hp = 150 * (1 - 25 / 150) = 125

[ezze]

Another simple solution is remove the Fortify Health extra HP before the regular ones.
E.g., you have 50 regular HP and 10 Fortify Health HP and you got hit for 8 your new situation is 50 regular, 2 fortify. Again from 50/10, if you get hit for 20 damage after you have 40HP and the Fortify Health effect is removed.

This is not risky and fairly natural, being hit basically makes your spell last less.

This is how we do in pen and paper rpg games.

[Chris]

The simplest solution is to simply not alter the current health when the fortify wears off, except to clamp it to the newly reduced maximum. Effectively, fortify health would have the effect of temporarily increasing the max health, and is bundled with an heal by the same amount. So when the effect wears off, the max health returns to normal but it doesn't explicitly "unheal" you (the engine just ensures the current health remains less than or equal to the maximum, as usual).

Though I don't know the cost of fortify health effects compared to normal restore health effects. A fortify would have to cost more than a restore since the former would include the latter, but with an added temporary over-charge. A fortify with a 0 (one frame) duration would essentially just be a restore.

[AshSlave]

A fortify would have to cost more than a restore

That alone would make a fortify spell quite expensive with high duration, yet much less useful than a restore one with same duration and magnitude. You'd have to cast fortification right before getting hit to make the spell worth the cost. Which could actually work well if you also change casting system to be like in Skyrim. Or you could add a new value that governs the cost scaling with duration and make it lower for fortify, other spells might benefit from it too.

But by this point it's not the simplest solution already. And it will also be exploitable by quickly equipping and unequipping item permanently enchanted with fortify health, which can be done faster than once per second and thus provide better healing.