Illusion Queries

[Mariania]

I'm trying to build a dungeon with a lot of illusions in it. Hopefully the players will get a decent distance in before they realize they're illusions.

According to the SRD, some illusions have thermal components and some have tactile. Just in general this might be based off the illusion sub-school or the specific illusion. I'm asking about general cases where these components are present.

If someone were to cast an illusion of lava on the floor with an illusion that has thermal components, it would give off heat, correct? Would that heat be enough to damage characters in contact with it who failed their will saves? Or would they just feel great non-mechanical heat?

If there was a tactile illusion of a hallway over blank wall, what would happen to characters who failed their will saves who attempted to walk down the hall? Would they still hit the wall even though the illusion is tactile? How far could they get before the illusion broke down?

[Troacctid]

Because figments and glamers (see below) are unreal, they cannot produce real effects the way that other types of illusions can. They cannot cause damage to objects or creatures, support weight, provide nutrition, or provide protection from the elements. Consequently, these spells are useful for confounding or delaying foes, but useless for attacking them directly.

So no damage, no heat dangers (http://www.d20srd.org/srd/environment.htm#heatDangers), etc. Unless it's a shadow, in which case the illusion is partially real and can cause actual harm.

[Khatoblepas]

Regarding the Illusion of a Hallway:

If they ran into the wall, they'd hit it and react as if they hit a wall, but wouldn't know why. At the most, I'd probably deal 1d3 points of damage if they were running, and give them a Reflex save to stay standing. I know people who have walked into doors and walls and broken their nose, so.

Regarding the lava:

They'd feel the heat, and react as though the place was hot, but no actual harm would befall them.

AD&D 2e had a way more detailed system for dealing with illusions - namely the concept of "Illusionary Damage", which was ticked away seperately from real damage, and if the combination of both was greater than your hit points, you had to make a System Shock roll or die. Also, falling into illusionary lava would also provoke a System Shock roll, as your body actually believes that you're being burnt alive, even though you're perfectly fine.

I never use "or die", though, usually you just go unconscious from going into shock.

To replicate this in 3e, I'd make sure to tally all illusion damage seperately (dealing 20d6 points if a player submerges themselves in illusion-lava when they think it's real, etc), and once you've got a moment to properly assess the situation (you're out of the lava and notice you're not a charred corpse), that "damage" vanishes instantly. But in the heat of the moment, it might be the difference between staying fighting and being too afraid to continue.

[Nettlekid]

What Illusions have tactile, non-thermal effects?

[Mariania]

I was reading this thread (http://www.giantitp.com/forums/showthread.php?285123-Looking-for-DM-advice-quot-I-walk-through-the-Illusion-quot) and it was mentioned that some illusions can have tactile components, such as Veil and Mirage Arcana. For my purposes, I would be using Mirage Arcana or some similar homebrew spell.

[Duke of Urrel]

According to the SRD, some illusions have thermal components and some have tactile. Just in general this might be based off the illusion sub-school or the specific illusion. I'm asking about general cases where these components are present.

Remember that illusions of the Figment subschool can only add features to a space; they cannot seemingly take anything away that is real. The illusion of a hallway over a blank wall could only be produced by a spell of the Glamer subschool. Of course, the only illusion I know with a (non-thermal) tactile component is the Mirage Arcana spell, which is a Glamer.


If someone were to cast an illusion of lava on the floor with an illusion that has thermal components, it would give off heat, correct? Would that heat be enough to damage characters in contact with it who failed their will saves? Or would they just feel great non-mechanical heat?

When you are burned and you feel pain, I believe this feeling is the sensation of damage, not the sensation of heat itself. Since illusory heat cannot cause any real damage, I believe it also cannot cause any real pain. Therefore, I believe that a thermal illusion cannot make you feel burned; it can only make you feel uncomfortably hot, at the most.

On the other hand, a lava floor looks really scary and surely must feel uncomfortably hot even from some distance away (though never outside the range of the illusion's area of effect). Nobody who believes that a floor of illusory lava is real will dare to set foot on it without serious protection against heat (or lots of Hit-Points to "burn"). If you land on illusory lava by accident or because you were pushed, I believe you experience heat that is no worse than uncomfortable, which instantly makes you disbelieve the illusion. If you can show others that the lava cannot harm you, they should automatically disbelieve, too.

If you are well protected enough to be totally immune to heat, you may not be surprised by the failure of illusory lava to feel any worse than uncomfortably hot, because you may attribute this effect to your magical protection. In this case, you may not disbelieve the illusion merely because it does not harm you. However, if you are only well protected enough to suffer reduced damage, you will be surprised that you don't feel any burning sensation at all while you are walking on lava. This experience should be enough to make you instantly disbelieve the illusion.


If there was a tactile illusion of a hallway over blank wall, what would happen to characters who failed their will saves who attempted to walk down the hall? Would they still hit the wall even though the illusion is tactile? How far could they get before the illusion broke down?

I agree with what Khatoblepas said about the possibility of taking damage when you run into a wall that you thought was an open hallway. I would add only that this damage could be greater for a creature moving at running speed, less for a creature moving at walking speed, or nil for a creature carefully searching one five-foot cube at a time.