ThirdWizard said:
It's some designers misinterprieting how immediate actions work and thinking they work like Instants (or for old schoolers Interupts) in Magic: the Gathering. Nowhere does it say that immediate actions work like readied actions or can be used in such a way as to interrupt an action that has already taken place.
They aren't triggered by something. You can't interrupt an immediate action with another immediate action. They occur when you say it, as you say it. These spells are laregely useless by the rules and should just be ignored.
Well, let's go through the details:
SRD said:
Free Action
Free actions consume a very small amount of time and effort. You can perform one or more free actions while taking another action normally. However, there are reasonable limits on what you can really do for free.
Swift Action
A swift action consumes a very small amount of time, but represents a larger expenditure of effort and energy than a free action. You can perform only a single swift action per turn.
Immediate Action
An immediate action is very similar to a swift action, but can be performed at any time — even if it's not your turn.
A swift action takes very small amount of time, but a bit more effort and energy than a free action. Nothing about it actually taking more time than a free action though.
So, essentially, a swift action is exactly the same as a free action with the limitation that you can only do 1 a turn.
You can take one or more free actions WHILE taking another action. For instance, you can speak while you are attacking someone since they can both be done at the same time.
Later in the SRD:
SRD said:
You can take a swift action any time you would normally be allowed to take a free action.
Using an immediate action on your turn is the same as using a swift action, and counts as your swift action for that turn.
To get an idea of what sorts of things we can do with a free action and use that as a basis for when we can use immediate actions:
SRD said:
If you have a base attack bonus of +1 or higher, you may draw a weapon as a free action combined with a regular move.
You can mount or dismount as a free action with a DC 20 Ride check.
You can stop concentrating on an active spell as a free action.
A character can spend 1 action point as a free action when fighting defensively.
A character can spend 1 action point as a free action to increase the effective caster level of one of his spells by 2. He must decide whether or not to spend an action point in this manner before casting the spell.
WINGOVER. A flying creature with this feat can change direction quickly once each round as a free action.
RAPID RELOAD. The time required for you to reload your chosen type of crossbow is reduced to a free action.
(under heading Free Actions)Prepare spell components to cast a spell
Drawing ammunition for use with a ranged weapon (such as arrows, bolts, sling bullets, or shuriken) is a free action.
Improved Grab (Ex): ...can attempt to start a grapple as a free action.
So, what we know is that you can take free actions (and therefore immediate actions) while moving(changing directions using wingover, drawing a weapon while moving), while casting a spell (to manipulate material components), in between attacks (drawing with quick draw, dropping weapons, reloading using rapid reload), and after you hit (Improved Grab).
We also know there is an immediate spell (Close Wounds) that specifically says it can be used even after damage is done to retroactively heal someone so they never took the damage. Of course this is specifically spelled out in this spell, so it may not apply to all immediate actions.
However, at the very least, we can assume that if an enemy can attack someone, then hit, then take a free action to grapple that if an enemy attacks someone, hits, then you can declare an immediate action between hitting and damage being rolled.