Use Your Illusion
Posted: Tue Dec 04, 2007 8:14 am

Question:
When an illusion is cast, who gets to roll a will save, and when?
One understanding is that everyone gets to attempt a save upon coming across the illusion.
If you disguise self and walk into a full tavern, everyone gets an attempt.
Of course, this means that 1 out of every twenty people is going to pierce your illusion. Pierced illusions show up as the illusion blurred over what it actually there, so you become VERY noticeable. Afterwards, they'd surely tell their friends, who now have a chance to actively disbelieve, etc... ends up that a mage with 50 gazillion int, Greater Spell Focus, illusion, casting permanent image will not fool an inn full of commoners.
A second understanding is that you don't get to roll unless you 'interact' with the illusion. Now this has several levels of meaning.
Interact can mean passively interacting or actively interacting. Passively means that the first case above is in effect. I see you, that's your illusion that I'm passively interacting with by seeing so I get to roll a saving throw.
Actively interacting with means you are actually touching, focusing on, smelling, etc.
Page 173 of the PHB (3.5) talks about Saving Throws and Illusions, which it labels as 'disbelieving'. It says that creatures encountering an illusion usually do not get a saving throw until they study it carefully or interact with it in some fashion.
While some might say that merely 'seeing', 'smelling', 'hearing' the illusion counts as interacting with it... the idea that you have encountered the illusion seems to say that you are seeing, hearing, smelling it. So now that you've encountered it, you don't usually get a save unless...
This feels like you don't save on a disguise illusion merely by laying eyes on it.
So, throwing it out there... when do you think folks make saves on illusions? Immediately upon encountering them, or only after something has given you a reason to believe it might be an illusion?