Disbelief and Interaction: All three of the subschools above tend to have saving throw lines that say “Will disbelief,” but they differ in how those saving throws apply. Phantasms directly assail a creature’s mind, so the creature automatically and immediately receives a saving throw to disbelieve a phantasm. Figments and glamers, however, have the more difficult-to-adjudicate rule that creatures receive a saving throw to disbelieve only if they “interact” with the illusion.

But what does it mean to interact with an illusion? It can’t just mean looking at the illusion, as otherwise there would be no need to make the distinction, but drawing the line can be a bit tricky. Fortunately, the rules can help to define that difference. A creature that spends a move action to carefully study an illusion receives a Will saving throw to disbelieve that illusion, so that is a good benchmark from which to work.

Using that as a basis, interacting generally means spending a move action, standard action, or greater on a character’s part. For example, if there were a major image of an ogre, a character who tried to attack the ogre would receive a saving throw to disbelieve, as would a character who spent 1 minute attempting a Diplomacy check on the ogre. A character who just traded witty banter with the ogre as a free action would not, nor would a character who simply cast spells on herself or her allies and never directly confronted the illusory ogre. For a glamer, interacting generally works the same as for a figment, except that the interaction must be limited to something the glamer affects. For instance, grabbing a creature’s ear would be an interaction for a human using disguise self to appear as an elf, but not for someone using a glamer to change his hair color. Similarly, visually studying someone would not grant a save against a glamer that purely changed her voice.

Disbelief and Interaction: All three of the subschools above tend to have saving throw lines that say “Will disbelief,” but they differ in how those saving throws apply. Phantasms directly assail a creature’s mind, so the creature automatically and immediately receives a saving throw to disbelieve a phantasm. Figments and glamers, however, have the more difficult-to-adjudicate rule that creatures receive a saving throw to disbelieve only if they “interact” with the illusion.

But what does it mean to interact with an illusion? It can’t just mean looking at the illusion, as otherwise there would be no need to make the distinction, but drawing the line can be a bit tricky. Fortunately, the rules can help to define that difference. A creature that spends a move action to carefully study an illusion receives a Will saving throw to disbelieve that illusion, so that is a good benchmark from which to work.

Using that as a basis, interacting generally means spending a move action, standard action, or greater on a character’s part. For example, if there were a major image of an ogre, a character who tried to attack the ogre would receive a saving throw to disbelieve, as would a character who spent 1 minute attempting a Diplomacy check on the ogre. A character who just traded witty banter with the ogre as a free action would not, nor would a character who simply cast spells on herself or her allies and never directly confronted the illusory ogre. For a glamer, interacting generally works the same as for a figment, except that the interaction must be limited to something the glamer affects. For instance, grabbing a creature’s ear would be an interaction for a human using disguise self to appear as an elf, but not for someone using a glamer to change his hair color. Similarly, visually studying someone would not grant a save against a glamer that purely changed her voice.