"Subtractive" illusions: can Silent Image make an illusary pit?

[Damon_Tor]

Can an illusion spell be used to create the appearance of empty space?

For example, enemies are chasing me down a hallway: I turn around and cast "Silent Image" making it appear that there's a 15 foot pit between us, even though the hallway has a smooth, flat floor.

Is that an appropriate use of the spell? To make it seem as though something that is there (the floor, in this case) isn't?

Silent Image's text reads "You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube." I can accept that a pit is not an object, but what exactly would distinguish it from a "visible phenomenon"? Google tells me the definition of phenomenon is "a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question." That's about as subjective as you can get: not helpful.

[Personification]

Can an illusion spell be used to create the appearance of empty space?

For example, enemies are chasing me down a hallway: I turn around and cast "Silent Image" making it appear that there's a 15 foot pit between us, even though the hallway has a smooth, flat floor.

Is that an appropriate use of the spell? To make it seem as though something that is there (the floor, in this case) isn't?

Silent Image's text reads "You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube." I can accept that a pit is not an object, but what exactly would distinguish it from a "visible phenomenon"? Google tells me the definition of phenomenon is "a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question." That's about as subjective as you can get: not helpful.

I would actually rule that as a 15X15 ft plane on which there is a perfect "painting" of a(n arbitrarily deep) pit resting on top of the ground, so it works, but not for the listed reason.

[MaxWilson]

Can an illusion spell be used to create the appearance of empty space?

For example, enemies are chasing me down a hallway: I turn around and cast "Silent Image" making it appear that there's a 15 foot pit between us, even though the hallway has a smooth, flat floor.

Is that an appropriate use of the spell? To make it seem as though something that is there (the floor, in this case) isn't?

Silent Image's text reads "You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube." I can accept that a pit is not an object, but what exactly would distinguish it from a "visible phenomenon"? Google tells me the definition of phenomenon is "a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question." That's about as subjective as you can get: not helpful.

As I interpret the spell, subtractive illusions are not appropriate. You're creating a phantom object, not a hole in a real object. That would be a different spell.

[Ganymede]

A space where nothing visible exists, such as a hole or a pit, is not a visible phenomenon, for obvious reasons. You're essentially asking Silent Illusion to make something invisible, which the spell cannot do.

You could make a patch of floor look like a black square perhaps, or even a two dimensional picture of a hole, but it might not stand up to visual scrutiny.

[DrowPiratRobrts]

There are lots of conflicting opinions on this. I think it's fine, but a lot of people certainly disagree. My reasons are as follows:

1. I interpret "visual phenomenon" much in the same way you do.

2. The spell says that the "image appears at a spot you choose." It says nothing about the spot being unoccupied when plenty of other spells and abilities clearly do.

3. Even if you disagree with this you could still make a 2D image that holds up at least as long as one's perspective doesn't change.

4. I have yet to encounter and RAW rulings that approach saying you can't do this and I think people who jump to RAI are often making assumptions in this case (though I'm open to my mind being changed on this issue).

5. I think it's less fun for the player and for the party. Even if I as a DM have to suffer a little from crazy illusions, it's worth it if the players have a much better time because of it.

EDIT: 6. I forgot this one. Maybe one of the most important. You aren't actually changing anything in the space physically. You aren't making something truly appear, rather it appears in one's mind. You perceive it as real, but this is overcome with an intelligence check. It's magic.


So in general I rule illusion magic as more powerful than a lot of others might. It doesn't break the game and I like seeing what players come up with when thinking up illusions. I would hate to play in a game as an illusion wizard where the one thing I can do better than any other class gets taken away because the DM doesn't want to deal with it (or whatever other reasons people will provide on this thread). Honestly, the way some people have said they rule illusions makes me wonder why anyone in their games would ever choose to cast an illusory spell.

Again, this is just my opinion and the way I typically rule. There could be extenuating circumstances, and I'm cool with people running their game how they want. I just hate when someone figures out several sessions into a game that their DM is going to put tons of restrictions on all the illusion magic they decided to learn. It's one of the biggest things I talk about with a DM before playing in a game.

[DrowPiratRobrts]

A space where nothing visible exists, such as a hole or a pit, is not a visible phenomenon, for obvious reasons. You're essentially asking Silent Illusion to make something invisible, which the spell cannot do.


A pit isn't invisible though...it's as visible as the rest of the ground. It has walls of dirt/rock/whatever ground material. It has width and height. It has a volume. It casts a shadow into the hole that changes with the lighting. It doesn't have anything to do with invisibility.

Would you allow the spell to make a closed door appear open?

Would you allow the spell to make a messy room appear clean with toys put away on shelves?

Would you allow the spell to make a full glass of mead appear empty?

[Man_Over_Game]

There are lots of conflicting opinions on this. I think it's fine, but a lot of people certainly disagree. My reasons are as follows:

1. I interpret "visual phenomenon" much in the same way you do.

2. The spell says that the "image appears at a spot you choose." It says nothing about the spot being unoccupied when plenty of other spells and abilities clearly do.

3. Even if you disagree with this you could still make a 2D image that holds up at least as long as one's perspective doesn't change.

4. I have yet to encounter and RAW rulings that approach saying you can't do this and I think people who jump to RAI are often making assumptions in this case (though I'm open to my mind being changed on this issue).

5. I think it's less fun for the player and for the party. Even if I as a DM have to suffer a little from crazy illusions, it's worth it if the players have a much better time because of it.


So in general I rule illusion magic as more powerful than a lot of others might. It doesn't break the game and I like seeing what players come up with when thinking up illusions. I would hate to play in a game as an illusion wizard where the one thing I can do better than any other class gets taken away because the DM doesn't want to deal with it (or whatever other reasons people will provide on this thread). Honestly, the way some people have said they rule illusions makes me wonder why anyone in their games would ever choose to cast an illusory spell.

Again, this is just my opinion and the way I typically rule. There could be extenuating circumstances, and I'm cool with people running their game how they want. I just hate when someone figures out several sessions into a game that their DM is going to put tons of restrictions on all the illusion magic they decided to learn. It's one of the biggest things I talk about with a DM before playing in a game.

There is one particular flaw with this, which is that the Illusion Wizard can make objects within illusions real. If that's the case...what happens?

Let's say I have an illusory pit inside of a real floor, and there's treasure at the bottom of the pit. And I can make an illusory object real.

The Pit might not be an object, but the treasure inside the pit is. The pit isn't real, so I can't reach into it without touching the real floor underneath it, but yet the treasure at the "bottom" of the pit is a real object that's....suspended inside of the floor?

Can I still pick it out of the non-existent pit, or do I see inside of the floor via the pit to see the real treasure but I'm unable to actually touch it? If the second part is true, am I technically seeing THROUGH the floor?


These mechanics don't fit the ruling too much, and trying to make a narrative that fits this ability seems wrong no matter how I make it. The easiest thing to do is to just say that the treasure isn't a valid target, but why wouldn't it be, if the illusion of a pit is a valid choice? It's not that the illusion of a treasure that's the problem, it's the fact that it's an illusion of emptiness inserted into a physical object that's the problem.

The treasure's not the problem, the problem is the pit.

[Tanarii]

No.

You cannot make actual objects such as the ground invisible. If it overlaps the image of your "empty" pit, what folks will see is the ground.

Kinda.

It can make a 2 dimensional image that looks like a pit from a specific place. Like those chalk drawings on sidewalks.

IMO visible phenomena means fog, mist, etc. rain. A creeping glowing eldritch ectoplasmic tendril reaching out. Although that starts to fall under "object" too.

[Ganymede]

A pit isn't invisible though...it's as visible as the rest of the ground. It has walls of dirt/rock/whatever ground material. It has width and height. It has a volume. It casts a shadow into the hole that changes with the lighting. It doesn't have anything to do with invisibility.

If a pit were not invisible, you would not be able to see what lies at the bottom and sides of it, nor would a shadow be able to reach the floor.

A pit, hole, or gap is not a thing; it is an absence of a thing, and Silent Image cannot make something disappear.




Would you allow the spell to make a closed door appear open?

Would you allow the spell to make a messy room appear clean with toys put away on shelves?

Would you allow the spell to make a full glass of mead appear empty?

No, no, and no. Silent Image cannot make objects disappear.

[Sception]

A pit is a phenomenon you can see, that can be of the appropriate size. You can't make a hole or window that lets you see actual things behind, or even fake things if those things are bigger than the listed size, but a fake hole or little illusory room no bigger than the given limit is fine, or at least would be in my games.

[Tanarii]

Would you allow the spell to make a closed door appear open?

Would you allow the spell to make a messy room appear clean with toys put away on shelves?

Would you allow the spell to make a full glass of mead appear empty?

No, no, and no. Silent Image cannot make objects disappear.
in the case of the messy room, you could get tricky. Move the "clean" floor up enough so that it conceals the the toys. Of course, the gig will be up the second someone steps on the "floor". Or if the edge at the doorway/entrance is visibly and obvious.

[DrowPiratRobrts]

There is one particular flaw with this, which is that the Illusion Wizard can make objects within illusions real. If that's the case...what happens?

Let's say I have an illusory pit inside of a real floor, and there's treasure at the bottom of the pit. And I can make an illusory object real.

The Pit might not be an object, but the treasure inside the pit is. The pit isn't real, so I can't reach into it without touching the real floor underneath it, but yet the treasure at the "bottom" of the pit is a real object that's....suspended inside of the floor?

Can I still pick it out of the non-existent pit, or do I see inside of the floor via the pit to see the real treasure but I'm unable to actually touch it? If the second part is true, am I technically seeing THROUGH the floor?


These mechanics don't fit the ruling too much, and trying to make a narrative that fits this ability seems wrong no matter how I make it. The easiest thing to do is to just say that the treasure isn't a valid target, but why wouldn't it be, if the illusion of a pit is a valid choice? It's not that the illusion of a treasure that's the problem, it's the fact that it's an illusion of emptiness inserted into a physical object that's the problem.

The treasure's not the problem, the problem is the pit.


This is a fair argument, and even though I disagree with you I want you to know that I understand your ruling. It's just not what makes most sense to me.

I would rule that the treasure is real, but it's buried underground. If you try to grab it you grab dirt and realize that this is an illusion because you interacted with the pit physically. You could then dig the treasure up if you can get to it in time (an hour if I remember correctly). I would also understand someone ruling that the treasure is pushed to the surface since it's the nearest unoccupied space.

You see, I'm not saying you make the dirt invisible or anything. Simply that you change the terrain to appear like you want it.

Let's say a wizard in my game is looking at the wall of a bad guy's house. She wants to cast Silent Image to make it appear as if the wall isn't there. I'd be fine with that, but I would 100% make her come up with how the room behind the wall looks. This isn't true invisibility because unless she knows what the room truly looks like in that moment by some other means. But then she would seldom need to make the wall "disappear." So she might make the illusion of a crumbling wall on this side of the building and then an old dining room with dusty furniture. In reality the room might be full of beds with sleeping goblins and bugbears. So there are certainly limits.

[DrowPiratRobrts]

A pit is a phenomenon you can see, that can be of the appropriate size. You can't make a hole or window that lets you see actual things behind, or even fake things if those things are bigger than the listed size, but a fake hole or little illusory room no bigger than the given limit is fine, or at least would be in my games.

This is my point exactly. You aren't seeing the real dirt below the ground. You're seeing what the caster imagines the dirt looks like. So if an orc is fighting you in their hut and you make an illusory pit right where they know a trap door sits just below the dirt, that might cause them to have advantage on their intelligence check in my game. They would be really hesitant to believe what they're seeing is real because it doesn't reflect the reality of the secret passage they built below their hut. It just looks like a pit with dirt walls.

[StoicLeaf]

I think you have to decide for yourself how illusions work in your game and then just continue from there (provided your interpretations don't break the game).

I think what it comes down to is whether an illusion is:

a) an actual physical object
b) a magical effect in an observer's mind

if you pick a), then creating negatives isn't going to work; you can make an optical illusion illusion of a pit that will work for some angles (I'd give adv. on checks). Keep in mind this will mean that creatures that don't rely on sight aren't going to be as easily deceived (i.e. major image will work, the rest won't as easily).
if you pick b) then yeah, you can create negatives, but keep in mind people will then use this to cast static invisibility fields for their party. Now while this isn't going to break your game, your players might find other ways to abuse it AND they might get super annoyed at you if you decide to use it against them..

"as you walk across the open field, 6 silent image fields dissolve and reveal 54 bandits waiting in ambush. roll initiative!"

[Damon_Tor]

There are some illusion spells that explicitly allow you to make subtractive illusions. Disguise self is one such. It could be argued Hallucinatory Terrain strongly implies that ability in some of its example effects. Are these "the exception that proves the rule?"

[Ganymede]

There are some illusion spells that explicitly allow you to make subtractive illusions. Disguise self is one such. It could be argued Hallucinatory Terrain strongly implies that ability in some of its example effects. Are these "the exception that proves the rule?"

And, of course, the classic example of an illusion spell that can make something disappear is Invisibility.

[Damon_Tor]

"as you walk across the open field, 6 silent image fields dissolve and reveal 54 bandits waiting in ambush. roll initiative!"

That could still happen, they just have to be hidden inside illusory boulders or something.

Ultimately, either way you rule this doesn't change much mechanically.

[StoicLeaf]

That could still happen, they just have to be hidden inside illusory boulders or something.

Ultimately, either way you rule this doesn't change much mechanically.

Oh I agree.
But I think a player would argue that a boulder is something they can interact with; it's something you can be suspicious of.
"nothing" isn't something you innately want to interact with.
Like I say, decide how you want to play it and give it a whirl!

[Knaight]

If you can do it with chalk you should probably be able to do it with magic, and you can do it with chalk.
http://www.illusionspoint.com/wp-content/uploads/2015/05/Eduardor-Bench-Pit-Chalk-Drawing.jpg

I've seen better, but it's surprisingly hard to google for, mostly because "chalk pit" is apparently a valid term for chalk quarries, and "chalk pothole" pulls up the guy who drew ***** around potholes to get a city to fill them.

[raygun goth]

I don't see why not.

If you can do it with chalk and a flat surface (https://www.google.com/search?q=3d+street+art&rlz=1C1CHZL_enUS727US727&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjr17zdg8HfAhXlp1kKHcVvAEEQ_AUIDigB&biw=1920&bih=889), why couldn't you do it with what is essentially a 3D rendering program that can make things more lifelike and realistic than any modeling program we have today?

[TheAxeman]

I would say yes but if they change their perspective to it compared to the one it was made at it will appear as blatantly false. So possible but probably not great implementation.

[Imbalance]

There are two kinds of people in the world:
Those who know Wile E. Coyote painted the tunnel entrance on the canyon wall and those who saw Roadrunner dash through it.

[DrowPiratRobrts]

I think you have to decide for yourself how illusions work in your game and then just continue from there (provided your interpretations don't break the game).

I think what it comes down to is whether an illusion is:

a) an actual physical object
b) a magical effect in an observer's mind



This is probably the crux of the issue. Without arguing why I think Option B makes more sense, the above examples of street art with chalk help show our side for those of us who rule that it's not only permissible but actually good and logical. If the illusion is fixed in your mind (edit: as contrasted to simply a drawing on the ground) then your perspective changing won't change how "realistic" the illusion seems. It's going to look like a pit no matter where you look at it from because it's an idea magically implanted in your mind, and everybody who watched Inception knows how powerful an idea can be. *BWWWWAAAAAHHHHH BWWWWWUUUUUMMMM* Cue the music.

[No brains]

I'd allow it just because making a creature think "Uh-oh, something's in the way" is not out of line with the power level of the spell.

I'd even allow there to be a little bit of a 3d effect, kind of like a lenticular comic book cover that almost makes a believable parallax.

Though this is still going to be beaten by an Int check or the creature trying to poke the hole with a stick. It's probably not going to hold the creature back for long.

I would pray for the day when this is used exactly right and one enemy looney tunes itself down a hole it thinks is fake. That's going to take a perfect storm of timing, conditioning, terrain, and creatures not being able to fly, climb, or even just JUMP to work.

[Damon_Tor]

I'd allow it just because making a creature think "Uh-oh, something's in the way" is not out of line with the power level of the spell.

I'd even allow there to be a little bit of a 3d effect, kind of like a lenticular comic book cover that almost makes a believable parallax.

Though this is still going to be beaten by an Int check or the creature trying to poke the hole with a stick. It's probably not going to hold the creature back for long.

I would pray for the day when this is used exactly right and one enemy looney tunes itself down a hole it thinks is fake. That's going to take a perfect storm of timing, conditioning, terrain, and creatures not being able to fly, climb, or even just JUMP to work.


Be running from a guy down a narrow corridor
Cast Silent Image to make a pit 6 foot pit that looks like its full of hunting traps
Guy stops until he figures out it's fake or maybe he jumps the pit
He catches up again
Cast another Silent Image that looks the same
See what he does
Repeat until he stops jumping over the pit
This time have an unseen servant unfold portable hole you've actually filled with hunting traps and just pretend to cast the spell


Out of curiosity, is there any kind of limit to how many hunting traps you can put in one square?

[DrowPiratRobrts]

I would pray for the day when this is used exactly right and one enemy looney tunes itself down a hole it thinks is fake. That's going to take a perfect storm of timing, conditioning, terrain, and creatures not being able to fly, climb, or even just JUMP to work.

This is now my Wizard's primary goal in life. Thank you.

[Man_Over_Game]

This is now my Wizard's primary goal in life. Thank you.

A bit in the opposite direction, but one of the dungeons I designed used illusions for its lethality.

Players are traveling through a tunnel that has an upwards slope. The players hear a click, and a boulder falls at the top of the tunnel and is rolling downwards. At the bottom of the slope appears to be solid floor, but in reality it's a spike pit illusioned to be a floor, and the boulder is also an illusion with realistic sounds and programmed movement. It's a lot more cost efficient to maintain 2 illusions and a pit than it is to replace a boulder that destroys your temple every time a fat rat runs by.

Additionally, it utilized a pathway of tiles, with dozens of gargoyles flanked on each side. Each tile activates a gargoyle that breathes flames, but not every gargoyle releases real flames. There's no obvious way to tell which tile is trapped and which are not. Upon stepping on the first tile, the stone door on the far side begins to close, and when it does, fireproof imps come to harass the players. The trick is the tiles. While they appear to be flat, they're actually marked in dwarven with a symbol of a flame, and simply are illusioned to appear flat. Investigation on the gargoyles, if you can get close enough, tells you which ones are real based on burn marks deep inside of their throats, but inspecting the tiles is a lot safer.

Enemies include:
A kobold wizard, hiding behind an illusory wall as he casts Illusory Dragon against you,
Several Giant Bats that attack you in a hall of mirrors (all creatures within the room are under the effects of Mirror Image, with the Mirrors being a sort of "mirror counter" that decreases each time a mirror is struck, or nullified all at once with a single Shatter spell.
Random creatures with Truesight, in a room filled with a combination of real and illusory spears jutting out of the walls and floors.


Just seemed like something that might fit what you might be interested in.

[Tanarii]

I think what it comes down to is whether an illusion is:

a) an actual physical object
b) a magical effect in an observer's mindNeither. It's a magical structure that exists in the world. So closer to (a). As indicated by the spells calling out physical interaction causing you to see through it. You can't physically interact with something in the mind.

But it doesn't matter either way. Even if it's in the mind, the spells that don't say they do don't stop you from seeing what's actually there unless they cover it up. So putting an illusion of a pit in the same place as the ground just means creatures see the ground.

2D optical illusions are a different matter of course. And regardless of it not actually being in creatures' minds, it's possible a DM might rule they work from any angle ... because magic.

[ThePolarBear]

A pit is a phenomenon you can see

A pit is not a phenomenon quite simply because a pit is not an event.

[Lonely Tylenol]

It can make a 2 dimensional image that looks like a pit from a specific place. Like those chalk drawings on sidewalks.

Or Wile E. Coyote’s fake tunnels!

[StoicLeaf]

Neither. It's a magical structure that exists in the world. So closer to (a). As indicated by the spells calling out physical interaction causing you to see through it. You can't physically interact with something in the mind.

But it doesn't matter either way. Even if it's in the mind, the spells that don't say they do don't stop you from seeing what's actually there unless they cover it up. So putting an illusion of a pit in the same place as the ground just means creatures see the ground.

2D optical illusions are a different matter of course. And regardless of it not actually being in creatures' minds, it's possible a DM might rule they work from any angle ... because magic.

I disagree with your assessment here.
The illusion blocks sight until you realise it's an illusion, at which point you see through it (literally).

[RedWarlock]

RAW, I don't think it works, though a creative combination of Invisibility and Silent Image might work.

As a DM, I would say that yes, you could do this, but with a Spellcraft-style check for an exceptional usage of the spell. DC 10 + (spell lvl) + 2*(number of enemies to fool).

[Talionis]

Raw this works. You can make an empty glass on a table. Your illusion is of air where air doesnt exist. You are only affecting the 15ft cube. The window that shows a room bigger than 15ft cube doesnt work because your illusions cant affect a space beyond 15ft. But you could project a window through a door of a 15ft cube room.

Nothing is really a void. You are not projecting empty space you are projecting space filled with air. Why is the pit different than a 15ft pool of water?

Nothing says illusions must be cast over space with only air.

The power allows you to make an empty glass container that people can see through. Or a 15ft glass wall.

The only real problem is when you try to change more than the 15ft cube. You cant let this increase the distance someone could otherwise see nor can you cheat the illusion to give the appearance you are affecting more than 15 ft.

[noob]

whenever an illusion is in the mind of a person or an image or a 156% real thing that works more on you when you realize it is an illusion depends on the subschool of the illusion spell

[Ganymede]

Raw this works. You can make an empty glass on a table. Your illusion is of air where air doesnt exist.

That's not subtractive. You're merely making an illusion of something visible (a glass) that wasn't there before. The illusion isn't of air but of a glass.




Nothing is really a void. You are not projecting empty space you are projecting space filled with air. Why is the pit different than a 15ft pool of water?

While it is true that air is not a "void" in the literal sense, it is a void in the sense we care about: you can't see it. This is important because Silent Image only lets you create visual phenomena, and something you can't see is axiomatically not a visual phenomena.




Nothing says illusions must be cast over space with only air.



True, I guess, but creating illusions inside of solid objects is a waste of time because no one can see through the solid object to see the illusion. If you make an illusory apple inside of a real barrel, no one will even see it because the barrel blocks line of sight to the apple.

[EggKookoo]

I'm on the side that says you can do it. But I don't see illusions as holograms. They're at least partially in your mind.

If you could bring a camera into D&D I'm not 100% sure it would capture an illusion. Although it might, but that would just be because magic is weird like that...

[Tanarii]

I disagree with your assessment here.
The illusion blocks sight until you realise it's an illusion, at which point you see through it (literally).
There's no illusion where the 'empty' is in an illusion of an empty pit. The illusion is only of the walls and floor of it.

So there's nothing to block seeing the actual ground.

[PhoenixPhyre]

I'd let it work at least once, because I'm a fan of people being creative and doing clever things. Easy to discover, so not that strong.

I let my party use a similar trick to sneak across empty ground against possible observation from above by creating a "painting" of the empty ground a bit higher up that they crawled under. Wouldn't work against multiple angles or stop concerted investigation, but against bored guards who had no idea that there was any threat? It's enough of a fig leaf.

[EggKookoo]

So there's nothing to block seeing the actual ground.

https://lh4.googleusercontent.com/_hVfE2qcyzXU/TduJmxeRpjI/AAAAAAAADHY/vlCY58crNTc/s800/kurt-wenner-street-art-7.jpg

Now imagine that effect being produced via magic, which would keep the perspective accurate as you moved around it. The chalk is flat, yet at the right angle it appears to have depth. Same thing with the illusion of a hole. It's still flat but the way it displays itself to you creates the appearance of depth.

[Chronos]

You don't see a pit. You see the walls and the floor of a pit. If you make the illusion of the walls and floor of a pit, then it'd be pointless, because nobody could see your walls and floor, because the real ground would be in the way.

And to those saying that you can do this with chalk, have you ever actually seen one of these chalk drawings? Not seen a photograph of it: Seen it with your own eyes. Because those things don't actually work, except from one very specific angle. With a still photograph, you can just put the camera in that one exact spot, but real creatures really present on the scene will be moving around and have two eyes and so on, which very quickly destroys the effect.

As for using magic to shift the illusion to match the perspective, there might be some higher-level spell that does that, and in fact it might be that that's how Invisibility works. But it's beyond the bounds of what Silent Image can do.

With all of that said, though... what about mirrors? A mirror is a real object (not a lack of one), so you should be able to make an illusion of one. But a real mirror lets you see images behind it. And in fact, a mirror on the floor in a room without distinguishing features would look just like a pit, until you got close enough to see your own reflection. There's really no way to allow a Silent Image of a mirror, without expanding the scope of the spell to do all sorts of things it's not supposed to be able to do.

[Aimeryan]

As mentioned by pretty much every poster before, the problem with a 2D image is depth perception (https://en.wikipedia.org/wiki/Depth_perception) - which you can easily get around if only viewed from one perspective, but tends to fail very quickly the moment that perspective changes, like those chalk drawings.

One possibility, however, is to make the image very slightly 3D (on the scale of millimeters) and employ autostereoscopy (https://en.wikipedia.org/wiki/Autostereoscopy). Given that this is made by magic that can make perfect visual constructions, the illusion should be much more capable than even that of integral imaging (https://en.wikipedia.org/wiki/Integral_imaging):


The result is a visual reproduction complete with all significant depth cues, including parallax in all directions, perspective that changes with the position and distance of the observer, and, if the lenses are small enough and the images of sufficient quality, the cue of accommodation — the adjustments of eye focus required to clearly see objects at different distances. Unlike the voxels in a true volumetric display, the image points perceived through the microlens array are virtual and have only a subjective location in space, allowing a scene of infinite depth to be displayed without resorting to an auxiliary large magnifying lens or mirror.

~~~

Now, I wouldn't expect such an illusion to be creatable by any green novice; it would require an extraordinary mind and a lot of experience. As such, I would have it require something like an Arcana skill check of some high DC (>20) to make an autostereoscopic illusion; a failure would require trying again next round, which they could do as long as they spend their action - the idea being the more time that is spent on creating it, the more likely they are to succeed in doing so.

RAW, however, there seems to be no check for the creation of complex illusions.

[Tanarii]

(Snipped image)

Now imagine that effect being produced via magic, which would keep the perspective accurate as you moved around it. The chalk is flat, yet at the right angle it appears to have depth. Same thing with the illusion of a hole. It's still flat but the way it displays itself to you creates the appearance of depth.
Follow the thread of conversation. It's about 3D images of Pits extending into the ground. Or an open doorway or window through a wall. Or making toys on the ground invisible.

I've already clearly stated my views on 2D overlays.

[EggKookoo]

I've already clearly stated my views on 2D overlays.

In the real world we can easily fool your eyes into seeing depth in a 2D overlay. Sure, we need you to be wearing polarized glasses to make it work, but that's part of what the magic is doing. In fact we can do it without the glasses but it's limited fidelity. Faking depth is not a difficult concept.

The description for illusions in the PHB, at least minor illusion, says the illusion visually changes to a creature once the creature has comprehended that it's an illusion. This means the effect isn't pure visual trickery like a hologram, but is, at least to some degree, projected directly into the viewer's mind. Convincing the subject that the illusion has depth could easily be a part of that.

[tieren]

I'd allow it in my games, I think it is the kind of thing the spell is supposed to be able to do.

In terms of mechanical effect what is the purpose of making an illusion of a 15- pit? My guess would be to slow pursuers. How much should it slow pursuers? If they are familiar with the area they may have knowledge of the corridor and suspect something is amiss. They may think the wizard formed an actual pit so they investigate, drop a stone in or dip a toe. An action or two are lost and the chase resumes. That is about what I would think the wizard could reasonably expect and an appropriate effect for the spell level (buy the party a few seconds).

[Man_Over_Game]

I'd allow it in my games, I think it is the kind of thing the spell is supposed to be able to do.

In terms of mechanical effect what is the purpose of making an illusion of a 15- pit? My guess would be to slow pursuers. How much should it slow pursuers? If they are familiar with the area they may have knowledge of the corridor and suspect something is amiss. They may think the wizard formed an actual pit so they investigate, drop a stone in or dip a toe. An action or two are lost and the chase resumes. That is about what I would think the wizard could reasonably expect and an appropriate effect for the spell level (buy the party a few seconds).

The really clever use of this concept is to make a 10x10 pit appear as a 30x10. Either they spend extra actions thinking it's real, trying to avoid falling in, or they dive headfirst into the real pit.

[DrowPiratRobrts]

With all of that said, though... what about mirrors? A mirror is a real object (not a lack of one), so you should be able to make an illusion of one. But a real mirror lets you see images behind it. And in fact, a mirror on the floor in a room without distinguishing features would look just like a pit, until you got close enough to see your own reflection. There's really no way to allow a Silent Image of a mirror, without expanding the scope of the spell to do all sorts of things it's not supposed to be able to do.

By your ruling you can't create an illusory pool of water or any reflective metal, which I'm fairly certain is listed specifically in at least one spell description. Be careful with that and make sure you think through the implications of how damaging that is to illusion magic. Do what you want at your table, but if you're going to say that we're "expanding the scope of the spell to do all sorts of things it's not supposed to be able to do," then at least provide some reasoning for why you know the exact scope of what the spell is supposed to be able to do, while the rest of us are reasoning with each other to try and figure it out.

So while many of us may disagree about the pit, creating a mirror seems obviously within the rules to me. You can explicitly create reflective materials in many illusion spells.

[Tanarii]

The description for illusions in the PHB, at least minor illusion, says the illusion visually changes to a creature once the creature has comprehended that it's an illusion. This means the effect isn't pure visual trickery like a hologram, but is, at least to some degree, projected directly into the viewer's mind. Convincing the subject that the illusion has depth could easily be a part of that.
No it doesn't. It means they're applying their intellect to prevent the magical structure from affecting them, from the false illusion their senses are being fooled into seeing. But it doesn't follow that means it's projected directly into their mind.

And this all has no bearing on a 3D image of walls and floor of a pit descending into the ground not preventing the actual ground from being seen. Silent Image cannot produce an image of "nothingness" or invisibility. It produces images of objects, not emptiness. If an empty something overlaps a real something, that's both a physical interaction (which immediately gives the illusion away anyway) and fails to prevent the object it's overlapping from being seen.

[DrowPiratRobrts]

A bit in the opposite direction, but one of the dungeons I designed used illusions for its lethality.

Players are traveling through a tunnel that has an upwards slope. The players hear a click, and a boulder falls at the top of the tunnel and is rolling downwards. At the bottom of the slope appears to be solid floor, but in reality it's a spike pit illusioned to be a floor, and the boulder is also an illusion with realistic sounds and programmed movement. It's a lot more cost efficient to maintain 2 illusions and a pit than it is to replace a boulder that destroys your temple every time a fat rat runs by.

Additionally, it utilized a pathway of tiles, with dozens of gargoyles flanked on each side. Each tile activates a gargoyle that breathes flames, but not every gargoyle releases real flames. There's no obvious way to tell which tile is trapped and which are not. Upon stepping on the first tile, the stone door on the far side begins to close, and when it does, fireproof imps come to harass the players. The trick is the tiles. While they appear to be flat, they're actually marked in dwarven with a symbol of a flame, and simply are illusioned to appear flat. Investigation on the gargoyles, if you can get close enough, tells you which ones are real based on burn marks deep inside of their throats, but inspecting the tiles is a lot safer.

Enemies include:
A kobold wizard, hiding behind an illusory wall as he casts Illusory Dragon against you,
Several Giant Bats that attack you in a hall of mirrors (all creatures within the room are under the effects of Mirror Image, with the Mirrors being a sort of "mirror counter" that decreases each time a mirror is struck, or nullified all at once with a single Shatter spell.
Random creatures with Truesight, in a room filled with a combination of real and illusory spears jutting out of the walls and floors.


Just seemed like something that might fit what you might be interested in.

Haha, I'll keep this in mind. Especially if my players get through Dragon Heist and into DotMM.

[DrowPiratRobrts]

No it doesn't. It means they're applying their intellect to prevent the magical structure from affecting them, from the false illusion their senses are being fooled into seeing. But it doesn't follow that means it's projected direction into their mind.

You've got to somehow account for creatures seeing different things when one passes the Int check and one fails. Do it however makes sense to you, but it's a very common interpretation that illusions happen, at least in part, in one's mind.

Edit: I won't go down the ontology rabbit hole if you don't want to though.

[tieren]

The really clever use of this concept is to make a 10x10 pit appear as a 30x10. Either they spend extra actions thinking it's real, trying to avoid falling in, or they dive headfirst into the real pit.

IMO, the REALLY clever use is to criss cross the top of the black pit with narrow boards running diagonally from side to side so the enemies try to cross single file in a zig zag pattern, slowing them down until some idiot falls off the board and they all realize they've been had.

Then later make illusions of the same boards over a real pit and watch them all charge into it.

[Tanarii]

You've got to somehow account for creatures seeing different things when one passes the Int check and one fails. Do it however makes sense to you, but it's a very common interpretation that illusions happen, at least in part, in one's mind.
Applying your mind to seeing what's really there doesn't mean the illusion is in your mind. It doesn't even imply it. OTOH physical interaction revealing the illusion implies it's an actual thing, not in the mind at all. As does the illusion being seen by all creatures.

For example, compare and contrast Phantasmal Force.

[EggKookoo]

No it doesn't. It means they're applying their intellect to prevent the magical structure from affecting them, from the false illusion their senses are being fooled into seeing. But it doesn't follow that means it's projected direction into their mind.

If you say so, but the description doesn't say anything like that. It says the illusion changes before your eyes once you know what it is.

Regardless, you can project 3D depth onto a 2D surface with a hologram. There's no reason you couldn't do it with an illusion. You could even hide an object on the floor with a flat illusion positioned above it but with an offset illusory/projected depth that compensates. Your eyes can only tell depth by how they focus on things, and if you trick out that focusing you can control the sensation of depth. It's how VR goggles work. Magical illusions just do that by virtue of being magical. Even if you don't buy that the illusion is directly affecting your visual cortex or whatever, it just has to mess with each eye individually.

[EggKookoo]

Example of illusory depth:

https://i2.wp.com/puzzlewocky.com/wp-content/uploads/2015/10/airplane-stereogram.jpg

[DrowPiratRobrts]

Applying your mind to seeing what's really there doesn't mean the illusion is in your mind. It doesn't even imply it. OTOH physical interaction revealing the illusion implies it's an actual thing, not in the mind at all. As does the illusion being seen by all creatures.

For example, compare and contrast Phantasmal Force.

That's a good example, but I read Phantasmal Force as making the distinction because only the affected creature can see it. That needs to be clearly written, especially since it stands up to all sorts of physical interactions and logical fallacies.

I'm not saying the illusion is completely mental, but it makes sense for it to be at least in part. If I'm hallucinating that a horse is standing in front of me and I see you walk through the horse and start talking to me, that's still a physical interaction from my perspective and it shows the horse to be false. It's all a matter of perception because if I close my eyes while you walk through the horse then open them, I won't have perceived the physical interaction and won't have reason to believe that I'm hallucinating.

I think you can make a strong case either way. I just happen to find the argument for as more persuading than the argument against.

[tieren]

Another favorite of mine is signs.

Make a few illusionary walls with a sign on the front that says in common, orcish, and goblin "This is an illusionary Wall".

Then running around later you can just cast an illusion of the sign itself on a real wall. After a couple of swap ups, the enemies will be really reluctant to ignore any illusion. By then a sign on the floor saying "Hidden Pit trap ahead" works nearly as well as an illusion of a real pit trap. Especially if you carry around a few real signs on parchment in a satchel (investigating the sign and seeing that its real may reinforce the illusion of a trap rather than dispelling it).

[DrowPiratRobrts]

Your eyes can only tell depth by how they focus on things, and if you trick out that focusing you can control the sensation of depth. It's how VR goggles work. Magical illusions just do that by virtue of being magical. Even if you don't buy that the illusion is directly affecting your visual cortex or whatever, it just has to mess with each eye individually.

That's a great point I hadn't thought about, which I find odd seeing as I work at a place centered around VR and technology.

[EggKookoo]

Another favorite of mine is signs.

Make a few illusionary walls with a sign on the front that says in common, orcish, and goblin "This is an illusionary Wall".

Then running around later you can just cast an illusion of the sign itself on a real wall. After a couple of swap ups, the enemies will be really reluctant to ignore any illusion. By then a sign on the floor saying "Hidden Pit trap ahead" works nearly as well as an illusion of a real pit trap. Especially if you carry around a few real signs on parchment in a satchel (investigating the sign and seeing that its real may reinforce the illusion of a trap rather than dispelling it).

Settle down, Satan.

[No brains]

Example of illusory depth:

https://i2.wp.com/puzzlewocky.com/wp-content/uploads/2015/10/airplane-stereogram.jpg

Here I am staring at am abstract symbol, attempting to ascertain its depth, but just ending up confused. Not only do I have no brains, I have no taste in art.

[Ganymede]

Here I am staring at am abstract symbol, attempting to ascertain its depth, but just ending up confused. Not only do I have no brains, I have no taste in art.

You have to cross your eyes, the way pursuing minions cross their eyes when they look at illusory pits.

[Luccan]

Given "visible phenomenon" isn't defined, it really comes down to how you interpret that particular phrase. If you interpret it to mean "something you can see" then yes, the illusion of a pit can be created. This is not the same as turning the ground invisible, any more than making it appear as if a room is full of boxes when you and your allies are hiding in it is. Or putting illusionary dirt over an actual pit makes the pit invisible.

[Ganymede]

Given "visible phenomenon" isn't defined, it really comes down to how you interpret that particular phrase. If you interpret it to mean "something you can see" then yes, the illusion of a pit can be created.

Umm... what?

You can't see a pit so it cannot possibly be "something you can see." If you could see a pit, you would not be able to see the pit's walls and floor because the pit would be blocking line of sight.


This is not the same as turning the ground invisible, any more than making it appear as if a room is full of boxes when you and your allies are hiding in it is. Or putting illusionary dirt over an actual pit makes the pit invisible.

Here, you're equating the blocking of line of sight with illusory boxes/dirt with erasing the ability of real ground/dirt to block line of sight. They are exact opposites.

I really don't think you thought any of this through before you hit Post.

[Sception]

Oh I agree.
But I think a player would argue that a boulder is something they can interact with; it's something you can be suspicious of.
"nothing" isn't something you innately want to interact with.
Like I say, decide how you want to play it and give it a whirl!

Note that just as the "nothing" would block the view of the bandits, so too would it block the view of everything else behind them. The distant horizon is a lot larger than a 5' cube, so you could not create an illusion of it with silent image. The best you could do is a matt painting effect. By comparison, an empty 5' pit can fit inside a 5' cube.

Again, the pit is not a "subtractive illusion". You're not making the ground invisible to reveal the real dirt underneath, you're imposing a fake illusion of a pit over the ground that's actually there.

You could impose an illusion of an empty 5' pit over one with simeone hiding in it, just like you could impose an image of plain ground with no pit over the same.

[EggKookoo]

Here I am staring at am abstract symbol, attempting to ascertain its depth, but just ending up confused. Not only do I have no brains, I have no taste in art.

I don't know if it qualifies as art. But not everyone can do it. I know people who swear the whole thing is a kind of scam.


You have to cross your eyes, the way pursuing minions cross their eyes when they look at illusory pits.

I find it's more a process of "uncrossing" my eyes. Like, I try to see a point about a foot behind my monitor. But my point is the magic of the spell handles that for you. After all, you don't need to mess with your own focal depth when watching a 3D movie or using VR.

[Imbalance]

Example of illusory depth:

https://i2.wp.com/puzzlewocky.com/wp-content/uploads/2015/10/airplane-stereogram.jpg

Is this meant to be two bombers flying in tandem? I definitely see two nose cones and two sets of tail wings, but they're so close on top of each other that I thought it was a biplane for a sec. Given the nature of the forum, my first perception was that the nearest object was a dragon, but maybe it's supposed to be smoke or a cloud? Weird pic.

[tieren]

Is this meant to be two bombers flying in tandem? I definitely see two nose cones and two sets of tail wings, but they're so close on top of each other that I thought it was a biplane for a sec. Given the nature of the forum, my first perception was that the nearest object was a dragon, but maybe it's supposed to be smoke or a cloud? Weird pic.

I noticed that too, but if I open the image in another tab it is bigger and the discordant parts merge together to create the 3D effect. Kind of neat glimpse behind the scenes of how these things work.

[EggKookoo]

Is this meant to be two bombers flying in tandem? I definitely see two nose cones and two sets of tail wings, but they're so close on top of each other that I thought it was a biplane for a sec. Given the nature of the forum, my first perception was that the nearest object was a dragon, but maybe it's supposed to be smoke or a cloud? Weird pic.

Yeah, I just glanced at the "3D" before posting it, then realized later it's a weird superimposition of two or more planes, or something. It was really just to demonstrate that your eyes can be made to perceive depth where there is none.

Here's a cooler one...

https://bw-1651cf0d2f737d7adeab84d339dbabd3-gallery.s3.amazonaws.com/images/image_1358453/file_1358453.jpg


I noticed that too, but if I open the image in another tab it is bigger and the discordant parts merge together to create the 3D effect. Kind of neat glimpse behind the scenes of how these things work.

Oh, ok, that explains why it didn't look wonky to me at first glance. You'd probably want to open up the above one as well.

[Imbalance]

I noticed that too, but if I open the image in another tab it is bigger and the discordant parts merge together to create the 3D effect. Kind of neat glimpse behind the scenes of how these things work.

It's a fair example to the point of the thread. I was thinking of these pictures, particularly one I saw when they first became popular in the '90's that was literally of a round hole in the middle of the image, probably meant to be a whirlpool. At least, that's what it looked like using the stare-through method. It's memorable to me because it was also the first one I managed to see by crossing my eyes, and the inverted image was much more intimidating.

I checked the above on another device with different resolution and can very clearly see a single bomber now.

[Imbalance]

Dragon is painful to cross-eye. Recommend stare-through.

[DrowPiratRobrts]

Umm... what?

You can't see a pit so it cannot possibly be "something you can see." If you could see a pit, you would not be able to see the pit's walls and floor because the pit would be blocking line of sight.



I'd love to make a dungeon for all you people who claim that you can't see a pit. It'd be super easy...

"Okay everyone, let's hope there are no spike pits ahead."

"If there are, we'll all be dead!"

*DM puts spike pit right in front of players who refuse to acknowledge what their eyes perceive, because they know for a fact that all pits are invisible.*

Easy TPK.


You probably mean that you can't see air, though that's not exactly true. Still I understand your point. You realize though that we aren't saying that you create the illusion and enemies can now see what's actually below the surface of the dirt right? Like if the area is rich with gold ore and the caster doesn't know that, then when you look at the walls of the pit you wouldn't see the gold because the caster didn't put it in the image. Contrarywise, if you dig to that exact spot that you believe you're actually seeing, you would find a big ole chunk of gold. You're not "literally" seeing through the ground. You're being tricked into believing that someone dug a hole that doesn't actually exist.

[DrowPiratRobrts]

I'm curious now if any of you on the negative side of this would allow someone to make an illusion of a small pond in the forest, provided it fit inside a 15 ft cube.

[EggKookoo]

I'm curious now if any of you on the negative side of this would allow someone to make an illusion of a small pond in the forest, provided it fit inside a 15 ft cube.

The only question I have is if the floor of the pond needs to be within the 15' cube (assuming you had something above it that needed you to make full use of the volume). I would probably rule that it would. You could still pull it off if your cube wasn't otherwise constrained -- just lower it -- but I think for balance reasons I'd have to say you can't fake depth out beyond the range of the feature or spell.

[Imbalance]

I'm curious now if any of you on the negative side of this would allow someone to make an illusion of a small pond in the forest, provided it fit inside a 15 ft cube.

I'd stock bass in it.

[DrowPiratRobrts]

The only question I have is if the floor of the pond needs to be within the 15' cube (assuming you had something above it that needed you to make full use of the volume). I would probably rule that it would. You could still pull it off if your cube wasn't otherwise constrained -- just lower it -- but I think for balance reasons I'd have to say you can't fake depth out beyond the range of the feature or spell.

That makes sense, I think...I'm not certain I know what you mean by the example but I get your conclusion. One solution for players would be to make the water murky enough where you couldn't see past a couple feet if the depth was that important. Yeah, fake depth is a tricky one I haven't thought much about.

But my larger point was that if anyone says you can't make a pit and also says you can make a pond then I just don't understand their logic. It's the exact same thing without water. So just say you're making a pond that's all dried up.

[EggKookoo]

That makes sense, I think...I'm not certain I know what you mean by the example but I get your conclusion. One solution for players would be to make the water murky enough where you couldn't see past a couple feet if the depth was that important. Yeah, fake depth is a tricky one I haven't thought much about.

So what I mean is, could you make a pit that appears to be 100' deep, even if the opening of the pit is a circle less than 15' in diameter? Technically the illusion fits within the 15' cube. For mechanical balance reasons I'd probably want to limit how much depth you could fake. I dunno. I'd have to think about that...

[DrowPiratRobrts]

So what I mean is, could you make a pit that appears to be 100' deep, even if the opening of the pit is a circle less than 15' in diameter? Technically the illusion fits within the 15' cube. For mechanical balance reasons I'd probably want to limit how much depth you could fake. I dunno. I'd have to think about that...

Yeah, I get that. I don't know for sure what I think about this either. On one hand it seems a little gamey, which is why I never liked falling back on the 2D image of a pit argument. On the other hand it doesn't seem to break anything. If you created an illusory chasm to the center of the planet and someone fell into it they'd just hit the ground...big deal right? Still, I'm not certain.

I'm imagining an illusion in a field. You could maybe make an illusion like Wile E. Coyote and Road Runner, where it seems though there's a long winding road. But as you circle the 15 foot cube you either lose the proper perspective or the road moves with you. Either of those would pretty much demand an intelligence check.

I'll have to think about this one to see if I can come down on one side or the other. It's like the 2D image illusion but you're working with 3 dimensions now. They did this a lot in the LotR movies to trick you into thinking that the hobbits and John Rhys-Davies where smaller than everyone else. Forced perspective in three dimensions is tricky though.

[Ganymede]

You probably mean that you can't see air

The highest level of confidence you're willing to assign to this is "probably?"


You realize though that we aren't saying that you create the illusion and enemies can now see what's actually below the surface of the dirt right?

There are people in this thread arguing exactly that, including you below.


Like if the area is rich with gold ore and the caster doesn't know that, then when you look at the walls of the pit you wouldn't see the gold because the caster didn't put it in the image. Contrarywise, if you dig to that exact spot that you believe you're actually seeing, you would find a big ole chunk of gold. You're not "literally" seeing through the ground. You're being tricked into believing that someone dug a hole that doesn't actually exist.

In order to see the illusion of this pit, which you've placed in the ground, you need literally see through all the real dirt and ground in the way. Silent Image cannot do this unless it somehow turned all that real dirt invisible. Mushy language like "you're being tricked" does not change the way the spell works.

[Imbalance]

In order to see the illusion of this pit, which you've placed in the ground, you need literally see through all the real dirt and ground in the way. Silent Image cannot do this unless it somehow turned all that real dirt invisible. Mushy language like "you're being tricked" does not change the way the spell works.

I feel like your imagination is locked on this concept. It's been talked about, but it doesn't really seem like anyone is making x-ray vision the point of the spell. The illusion is the image of a hole, not the absence of matter. The flat image of a hole can be placed anywhere with the reasonable expectation that a viewer's suspension of disbelief will overlook the reality of a non-hole where the image appears.

[DrowPiratRobrts]

The highest level of confidence you're willing to assign to this is "probably?"

Yes, I'm not certain what you intend when you say that pits cannot be seen. I think you probably mean the air in the pit, not the pit itself as a feature of the terrain. My point is that if you say you can't see a pit, that it's not a visual phenomenon, then there are going to be a lot of adventurers falling into pits all over the world instead of walking around them when they pass a perception check and spot them.




There are people in this thread arguing exactly that, including you below.



In order to see the illusion of this pit, which you've placed in the ground, you need literally see through all the real dirt and ground in the way. Silent Image cannot do this unless it somehow turned all that real dirt invisible. Mushy language like "you're being tricked" does not change the way the spell works.

My point is that you aren't actually, in reality, and in the ontological sense seeing through the ground. It appears that the ground is gone. You believe that the ground is gone. But what you're seeing is an illusion. It's a mirage.

Actually, I've seen a subtractive mirage in real life with my own eyes. On the Salt Flats in Utah you can look out onto the horizon. There are mountains overlapping each other in the distance. It looks like the mountain in front disappears and you can see the other mountain behind it. I was blown away when I saw it, because no matter where I walked or how hard I tried, I couldn't see the bottom corners of the closest mountains. Illusions do crazy things in real life. How much more with magic? Look at the photo below.

https://cdn2.foap.com/images/73f10bf5-9253-4fed-94dd-d499a772c495/w640.jpg?1526785556

[Ganymede]

I feel like your imagination is locked on this concept. It's been talked about, but it doesn't really seem like anyone is making x-ray vision the point of the spell. The illusion is the image of a hole, not the absence of matter. The flat image of a hole can be placed anywhere with the reasonable expectation that a viewer's suspension of disbelief will overlook the reality of a non-hole where the image appears.

Oh yeah, you can make a flat picture of a hole over the floor though, outside of very favorable circumstances, it will just look like a flat picture of a hole as opposed to a real hole (the illusion created by Silent Image can only alter its appearance when the spellcaster devotes an action to do so). Ask your DM to be sure.

[Ganymede]

Yes, I'm not certain what you intend when you say that pits cannot be seen. I think you probably mean the air in the pit, not the pit itself as a feature of the terrain. My point is that if you say you can't see a pit, that it's not a visual phenomenon, then there are going to be a lot of adventurers falling into pits all over the world instead of walking around them when they pass a perception check and spot them.

I don't appreciate being screwed with; there is no reason for me to deal with nonsense like this in my life when I can hit Ignore. I'ma need you to either rapidly mature or stop talking to me.



My point is that you aren't actually, in reality, and in the ontological sense seeing through the ground. It appears that the ground is gone. You believe that the ground is gone. But what you're seeing is an illusion. It's a mirage.

This isn't about the hypothetical limitations of spell-crafted trickery. This is about the actual capabilities and limitations of Silent Image. Silent Image does not create phantasms or hallucinations; it creates visually tangible objects and phenomena that exist three-dimensionally (or two-dimensionally) inside of a 15' cube.

[DrowPiratRobrts]

I don't appreciate being screwed with; there is no reason for me to deal with nonsense like this in my life when I can hit Ignore. I'ma need you to either rapidly mature or stop talking to me.




This isn't about the hypothetical limitations of spell-crafted trickery. This is about the actual capabilities and limitations of Silent Image. Silent Image does not create phantasms or hallucinations; it creates visually tangible objects and phenomena that exist three-dimensionally (or two-dimensionally) inside of a 15' cube.

I'm not screwing with you. I might have said something with my tongue in my cheek, but that's not the same thing. I wasn't trying to belittle you, and I'm sorry if you feel belittled. I was presenting my case. My point in the reduction to absurdity argument is that a pit, by many people's definition, is indeed a visual phenomenon. And further, as seen at the bottom right corner of the mountain in the picture above, this type of illusion is actually represented in real life three-dimensional space. It's visual. I stood there and could "see through the mountain" to the sky and to the other mountain behind it.

Edit: So I was seeing something, not just the absence of something. I was seeing the air and the further mountain, just like a goblin would see the dirt walls of the pit and the bottom and the worms and tree roots sticking out the side. It's not just the absence of something but the presence of new visual stimuli.

[Ganymede]

And further, as seen at the bottom right corner of the mountain in the picture above, this type of illusion is actually represented in real life three-dimensional space. It's visual. I stood there and could "see through the mountain" to the sky and to the other mountain behind it.

Sure, and if you wanted to duplicate this with Mirage Arcane, go on with your bad self.

It is still beyond the scope of Silent Image, tho.

[Beleriphon]

There is one particular flaw with this, which is that the Illusion Wizard can make objects within illusions real. If that's the case...what happens?

Let's say I have an illusory pit inside of a real floor, and there's treasure at the bottom of the pit. And I can make an illusory object real.

The Pit might not be an object, but the treasure inside the pit is. The pit isn't real, so I can't reach into it without touching the real floor underneath it, but yet the treasure at the "bottom" of the pit is a real object that's....suspended inside of the floor?

Can I still pick it out of the non-existent pit, or do I see inside of the floor via the pit to see the real treasure but I'm unable to actually touch it? If the second part is true, am I technically seeing THROUGH the floor?

Illusionists clearly run on Wiley Coyote and Road Runner logic. The painted tunnel is real to the bird, but not the coyote.

[EggKookoo]

It is still beyond the scope of Silent Image, tho.

"You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube."

A hole in the floor is a visible phenomenon.

The real question is, can silent image create the visual impression of depth on and orthogonal to a 2D surface, the way we can with holography, VR, or 3D media (or mirrors, for that matter)? That's certainly something ultimately for the DM to lock down but there's nothing in the spell's description that prohibits it. AFAIK there's no overall prohibition on that kind of thing for illusions in general, the way there is about illusions emitting light. Which itself is weird -- it should be that illusions can emit light but that light won't be cast on nearby non-illusory objects, but maybe that's too wordy and probably a topic for another thread.

[DrowPiratRobrts]

it should be that illusions can emit light but that light won't be cast on nearby non-illusory objects, but maybe that's too wordy and probably a topic for another thread.

I think we've effectively got that though since the color/brightness/hue of everything in the illusion is up to you. You could make the illusion of a statue appear as if the sun was beating down brightly on it even in a rainstorm right? Like you said, maybe this is another thread though.

[Ganymede]

A hole in the floor is a visible phenomenon.

If the hole is visible, you would not be able to see its sides and floor because the hole would be blocking line of sight to them. A lack of visual phenomena is, axiomatically, not a visible phenomenon.

I mean, you can see that there is nothing within the bounds of the hole, but "nothing" is just a lack of "something," not a visual phenomenon in and of itself.



The real question is, can silent image create the visual impression of depth on and orthogonal to a 2D surface, the way we can with holography, VR, or 3D media (or mirrors, for that matter)? That's certainly something ultimately for the DM to lock down but there's nothing in the spell's description that prohibits it.

Silent Image can create images of real things, so you could conceivably make an illusory Magic Eye poster hanging on a real wall that a viewer could inspect to see a hidden image. You could also make an arrangement of objects that look like one impossible object when viewed from a specific angle. In short, you could make an illusory version of anything you could conceivably produce in the real world.

What Silent Image cannot do is induce hallucinations or control a creatures perception, perspective, or how it processes visual information. For instance, Silent Image could not cause a person's individual eyeballs to see two different scenes, nor could it create a quasi 3D scene that alters itself in order to account for a viewer's change in perspective.

[Knaight]

The extent to which you need a particular perspective on those chalk drawings is a little overstated here - there's a range of options, and if you know that people will be looking from a fairly narrow set of angles (which hallways pretty much ensure) and are working on flat ground it's very doable. The particularity to angles starts cropping up in a big way when you're not relying on flat ground so much (e.g. any of those that incorporated benches into their design, where the angle changes on the bench are far more finicky), but you can just elevate the entire image enough with some fake slightly raised walls with an illusion in most terrain.

[Man_Over_Game]

There are two kinds of people in the world:
Those who know Wile E. Coyote painted the tunnel entrance on the canyon wall and those who saw Roadrunner dash through it.


If the hole is visible, you would not be able to see its sides and floor because the hole would be blocking line of sight to them. A lack of visual phenomena is, axiomatically, not a visible phenomenon.

I mean, you can see that there is nothing within the bounds of the hole, but "nothing" is just a lack of "something," not a visual phenomenon in and of itself.



Silent Image can create images of real things, so you could conceivably make an illusory Magic Eye poster hanging on a real wall that a viewer could inspect to see a hidden image. You could also make an arrangement of objects that look like one impossible object when viewed from a specific angle. In short, you could make an illusory version of anything you could conceivably produce in the real world.

What Silent Image cannot do is induce hallucinations or control a creatures perception, perspective, or how it processes visual information. For instance, Silent Image could not cause a person's individual eyeballs to see two different scenes, nor could it create a quasi 3D scene that alters itself in order to account for a viewer's change in perspective.

In context of Silent Image, I guess there are two kinds of players:


Those who say Silent Image creates holograms (Makes the most sense)
Those who say Silent Image can be any visual image (e.g. Virtual Reality) (I have seen people yell because they 'fell' down a Virtual Reality pit)


The spell identifies with #2, but the narrative better matches #1, and the heart of DnD is rewarding player creativity in a narrative story. As to which choice is more accurate, that's up to you.

--------

As for me, while I usually try to reward players for creativity, 5e is a game, and there's already a lot of bias towards Wizards, and even more towards Illusion Wizards, and Illusion users don't really need help standing out.

Ask yourself: Does this decision help a Spellcaster or a Skillmonkey more, and which of those two needs the help more?

In questions of ambiguity (such as with Silent Image options #1 and #2), I default to the one that leads towards better game balance (#1).

[EggKookoo]

What Silent Image cannot do is induce hallucinations or control a creatures perception, perspective, or how it processes visual information. For instance, Silent Image could not cause a person's individual eyeballs to see two different scenes, nor could it create a quasi 3D scene that alters itself in order to account for a viewer's change in perspective.

I'm not sold on that. I mean, I accept that you are and I'm not saying you've got a wrong interpretation of the description. I'm saying there's some ambiguity over it (what "visual phenomenon" means), and I feel free to interpret it such that the illusion could create a sense of depth. You would consider me houseruling but I wouldn't.

Curious -- and maybe there's some rule somewhere I haven't seen -- but can silent image create a functioning mirror on the wall? I know illusions typically can't emit light, but since you can actually see them then they either must be able to or they are able to reflect light. It has to be one or the other if your eyes are involved. On the other hand, maybe illusions don't deal with light at all but just put the image of themselves in your head, but if that were the case then they certainly should be able to emit or reflect light, or create the illusion of depth.

I know it's magic, and trying to apply logic and physics to it is counterproductive, but something's gotta give...


In questions of ambiguity (such as with Silent Image options #1 and #2), I default to the one that leads towards better game balance (#1).

Flat illusions with depth isn't that game-breaking. If you touch it it's revealed to be flat (and breaks the illusion). Home decor aside, it would probably have pretty limited use.

[Tanarii]

In order to see the illusion of this pit, which you've placed in the ground, you need literally see through all the real dirt and ground in the way. Silent Image cannot do this unless it somehow turned all that real dirt invisible. Mushy language like "you're being tricked" does not change the way the spell works.
right?

What this all comes down to is its fine if you can figure out a way to make a 2D overlay work. But thre is no way to make a 3D overlay of invisibility work that subtracts/makes invisible what's already there. Since that's not Silent Image does.

[Man_Over_Game]

Flat illusions with depth isn't that game-breaking. If you touch it it's revealed to be flat (and breaks the illusion). Home decor aside, it would probably have pretty limited use.

Find Familiar is probably considered the most powerful, game changing level 1 spell in the game.

Usually, that's not because it does one thing too particularly well, but because of the numerous things it provides you.

Choosing #2 for Silent Image is a step in a similar direction (since it also gains the benefit of #1), and both FF and SI are applicable to the same type of character/player.

-------

Take the Barbarian vs. the Paladin as another example. The Barbarian does one thing and does it well, where the Paladin doesn't do it quite as well but has a lot of different options at his disposal. However, the Paladin is almost always considered the better choice.

-------

Versatility IS power. Choosing to make something more versatile is choosing to make something better.

And does Silent Image/Spellcasters need to be made better?
Or alternatively, can those without Silent Image/Non-Spellcasters afford to be worse?

[Damon_Tor]

The way I see it, there are three ways illusions can work. Two of them would logically allow for negative space simulation.


They are entirely mental, existing only in the minds of observers. Some illusions explicitly work in this way.
They are created via light manipulation, blocking some photons while creating others.
They are magical constructs which interact with photons as if they were solid matter but do not usually interact with normal matter at all.


1 and 2 should allow negative space simulation.

[EggKookoo]

The way I see it, there are three ways illusions can work. Two of them would logically allow for negative space simulation.


They are entirely mental, existing only in the minds of observers. Some illusions explicitly work in this way.
They are created via light manipulation, blocking some photons while creating others.
They are magical constructs which interact with photons as if they were solid matter but do not usually interact with normal matter at all.


1 and 2 should allow negative space simulation.

4: They are a combination of the optical and mental. The optical component provides a kind of template that describes the overall illusion. These are either your #2 or #3 -- something that generates or interacts with light. The mental component "fills out" the optical one, giving it apparent solidity and opacity, and possibly even depth, form, and volume.

This interpretation would help explain why an illusion becomes less opaque, less "real," when the viewer realizes its true nature. Up to that point the mental component had been working.

[Aimeryan]

Kind of feel like my post was entirely missed, so reposting:


As mentioned by pretty much every poster before, the problem with a 2D image is depth perception (https://en.wikipedia.org/wiki/Depth_perception) - which you can easily get around if only viewed from one perspective, but tends to fail very quickly the moment that perspective changes, like those chalk drawings.

One possibility, however, is to make the image very slightly 3D (on the scale of millimeters) and employ autostereoscopy (https://en.wikipedia.org/wiki/Autostereoscopy). Given that this is made by magic that can make perfect visual constructions, the illusion should be much more capable than even that of integral imaging (https://en.wikipedia.org/wiki/Integral_imaging):


The result is a visual reproduction complete with all significant depth cues, including parallax in all directions, perspective that changes with the position and distance of the observer, and, if the lenses are small enough and the images of sufficient quality, the cue of accommodation — the adjustments of eye focus required to clearly see objects at different distances. Unlike the voxels in a true volumetric display, the image points perceived through the microlens array are virtual and have only a subjective location in space, allowing a scene of infinite depth to be displayed without resorting to an auxiliary large magnifying lens or mirror.

~~~

Now, I wouldn't expect such an illusion to be creatable by any green novice; it would require an extraordinary mind and a lot of experience. As such, I would have it require something like an Arcana skill check of some high DC (>20) to make an autostereoscopic illusion; a failure would require trying again next round, which they could do as long as they spend their action - the idea being the more time that is spent on creating it, the more likely they are to succeed in doing so.

RAW, however, there seems to be no check for the creation of complex illusions.

[Tanarii]

RAW, however, there seems to be no check for the creation of complex illusions.
If desired, a DM can call for a check for anything they feel requires it. That's RAW.

In this case though, a DM might reasonably determine that the ability to successfully create complex illusions that resist visually checking them out is already covered by the spellcasting DC, which is Investigated against.

[HappyDaze]

"You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube."

A hole in the floor is a visible phenomenon.


Sure, but so too is "an empty room" which when placed around the party does not render them invisible. For the same reason, the ground beneath your pit is not going to be rendered invisible, so the pit you're trying to create will never be seen, which means it effectively fails to be a visible phenomenon.

[Ganymede]

Given that this is made by magic that can make perfect visual constructions...

This is not correct as Silent Image does not create perfect visual constructions. It creates constructions that pass muster generally but fall apart under intense scrutiny.

Some illusion effects, such as Invoke Duplicity, specifically note that their illusions create perfect likenesses. Silent Image does not.

[Ivor_The_Mad]

I would say that you can just because you would be making them perceive a pit like how Personification said.

[bc56]

I would say yes.
"A pit" isn't nothing. It is an object, in a certain sense. It can be created using certain other forms of magic which create objects, such as the marvelous pigments.

[Aimeryan]

This is not correct as Silent Image does not create perfect visual constructions. It creates constructions that pass muster generally but fall apart under intense scrutiny.

Some illusion effects, such as Invoke Duplicity, specifically note that their illusions create perfect likenesses. Silent Image does not.

The construction can still be perfect (as in, the 3D structure); it merely requires some other quality to not be perfect in order to be detectable (different albedo, not interacting with dust, having an occasional slight flicker, etc.).

[EggKookoo]

Sure, but so too is "an empty room" which when placed around the party does not render them invisible. For the same reason, the ground beneath your pit is not going to be rendered invisible, so the pit you're trying to create will never be seen, which means it effectively fails to be a visible phenomenon.

I agree that deciding that silent image can make the appearance of a pit or pothole or some depression in a flat surface implies that you should be able to create the illusion of an empty room. At my table I would allow this but only when viewed from outside the room, as the illusion itself is really anchored to the doorway and is displaying the empty room to someone outside it. As soon as the observer enters the room, it would be revealed as an illusion. But I think it would retain visual and illusory integrity even if the observer got really close, as long as they never actually passed across the boundary.

You could also hide up against a wall by casting a silent image about 1-2 feet from the wall, with an image of the wall minus you there, with an offset depth to make it look like it was still the proper distance from the observer. Again this would be revealed as illusion if the observer tried to touch "past" the illusion to where they thought the wall was.

I understand not everyone agrees with this kind of usage but I don't think it's terribly unbalanced from a gameplay perspective. I would be willing to consider advantages on checks to perceive the true nature of any silent image that used depth-faking like this. At this point it hasn't come up in any of my games (I don't get a lot of spellcaster PCs).

[Chronos]

By your ruling you can't create an illusory pool of water or any reflective metal, which I'm fairly certain is listed specifically in at least one spell description.
To be clear, I'm not actually suggesting any particular interpretation. I'm saying that all interpretations are flawed, because every interpretation either fails to let the spell do something that it should be able to do, or lets the spell do something that it shouldn't be able to do. Any interpretation that allows for reflective surfaces also allows the spell to duplicate Invisibility, a higher-level spell, because there are real, physical arrangements of reflective surfaces that do that. If it ever actually came up in a game, and a player made the same arguments I'm making here, I'm not actually sure how I would run it.

[EggKookoo]

To be clear, I'm not actually suggesting any particular interpretation. I'm saying that all interpretations are flawed, because every interpretation either fails to let the spell do something that it should be able to do, or lets the spell do something that it shouldn't be able to do. Any interpretation that allows for reflective surfaces also allows the spell to duplicate Invisibility, a higher-level spell, because there are real, physical arrangements of reflective surfaces that do that. If it ever actually came up in a game, and a player made the same arguments I'm making here, I'm not actually sure how I would run it.

Right, nearly everything is a reflective surface. It's the fidelity of the reflection that varies.

Can you make an illusion of a dinner placement? Plate, flatware, glass, food? I mean that seems a pretty traditional thing to make an illusion of, but can the subject see themselves in the spoon? If not, what do they see? Can they see through the wine in the wineglass? Can they even see the wine in the wineglass through the sides? If you prohibit that, then illusions suddenly lose nearly any effectiveness. If you allow it, why can't you make a mirror?

[Imbalance]

Please don't stone me for this, but there is a sideways example that came to mind from the video game Monster Hunter Tri on Wii. There are two kinds of traps you can build to snare monsters (though they are literally consumables that you place), one of which is a pit trap. Your character does not dig a hole, rather the item essentially casts the illusion of a hole. With poor anti-aliasing it's not visually convincing, but mechanically it works, and the game changes the appearance of the creature who "falls into it" to that of its upper half struggling to claw its way out of the depth. There is even a terrain instance where your character can stand at a lower elevation than the placed trap, with the radius of the pit above you, and due to backface culling see through the underside of the "illusion" to the beast you've captured.

No, Silent Image is not going to make a hole that an Ogre will fall into (though I can picture one being convinced that he had), but wouldn't a creative spellcaster advance the illusory effect of their false pit by adding the image of something large lunging up out of it?

I think this is all i have to add. It just seems like much of this debate has gone circular now. I appreciate the opportunity to learn.

[Chronos]

That's exactly the problem, ChrisBasken: You should be able to make an illusion of a table set with silverware that looks like real silverware. You shouldn't be able to make an illusion of a magician's mirrored box that makes things disappear. But those both depend on the same functionality.

It can get even worse. You can make an illusion that looks like some other spell effect, right? But some spells produce effects which are opaque from one side, but transparent from the other, like Leomund's Tiny Hut. So that would mean that an illusion can do that, too. Combine one-way surfaces with mirrors, and you could do far more than even the magician's box. You could, for instance, make a 20-foot cube anywhere that makes everything you want inside of it invisible. Or put a 20-foot cube around an enemy that makes the entire world look to them however you want. And that's clearly beyond the power level of a what a 1st-level spell should be able to do.

[HappyDaze]

When you make the illusion of an empty room and there are people in the room, the people are still seen within the "empty" room. When you make the illusion of an empty pit and there is dirt (or whatever the floor is made out of) in that space, the dirt is still seen within the "empty" pit. In both cases, the illusion is worthless.

[EggKookoo]

When you make the illusion of an empty room and there are people in the room, the people are still seen within the "empty" room. When you make the illusion of an empty pit and there is dirt (or whatever the floor is made out of) in that space, the dirt is still seen within the "empty" pit. In both cases, the illusion is worthless.

The "pit" thing isn't you making an actual illusion of a pit. It's like placing a screen over the floor. On that screen is an image of a pit. The magic of the illusion gives it the appearance of depth, the same way we can do that with holography or 3D media. The image of the pit actually fools your eyes into seeing it go down. If you're north of the illusion, you can see the southern wall of the pit but not the northern one. If you're south of the illusion, you can see the northern wall but not the southern. If you walk around the illusion, that perspective shifts so you see the opposite wall.

So it's not like you're allowing people to see through something. You're masking something with something else that also has the ability to fake its focal depth from your eyes. That depth-faking is the contentious part.

[HappyDaze]

The "pit" thing isn't you making an actual illusion of a pit. It's like placing a screen over the floor. On that screen is an image of a pit. The magic of the illusion gives it the appearance of depth, the same way we can do that with holography or 3D media. The image of the pit actually fools your eyes into seeing it go down. If you're north of the illusion, you can see the southern wall of the pit but not the northern one. If you're south of the illusion, you can see the northern wall but not the southern. If you walk around the illusion, that perspective shifts so you see the opposite wall.

So it's not like you're allowing people to see through something. You're masking something with something else that also has the ability to fake its focal depth from your eyes. That depth-faking is the contentious part.

Yeah, no. I don't buy the "I'll make an illusion of an optical illusion so I can break the intent and limits of the spell" argument.

[Ganymede]

The "pit" thing isn't you making an actual illusion of a pit. It's like placing a screen over the floor. On that screen is an image of a pit. The magic of the illusion gives it the appearance of depth, the same way we can do that with holography or 3D media. The image of the pit actually fools your eyes into seeing it go down. If you're north of the illusion, you can see the southern wall of the pit but not the northern one. If you're south of the illusion, you can see the northern wall but not the southern. If you walk around the illusion, that perspective shifts so you see the opposite wall.

Silent Image does not create objects or phenomena that look different to different people, tho. The spell description says nothing even approaching that particular ability. This is like saying "I create a ball that looks blue to creature 1 and red to creature 2."

And no, Silent Image cannot duplicate a fictionalized perfection of cutting-edge modern day technology in the same way you can't Silent Image a cutting laser into existence under the justification that it is only light and light is a visual phenomenon.

And if any clarification is needed, I made an image macro that explains it.

https://i.imgur.com/jNEewmm.jpg
https://i.imgur.com/jNEewmm.jpg

[EggKookoo]

Yeah, no. I don't buy the "I'll make an illusion of an optical illusion so I can break the intent and limits of the spell" argument.

Illusions are fine, but illusions of illusions are RIGHT OUT!


Silent Image does not create objects or phenomena that look different to different people, tho. The spell description says nothing even approaching that particular ability. This is like saying "I create a ball that looks blue to creature 1 and red to creature 2."

I guess I'm not really trying to argue you can do this. But I'm not sure I accept that you can't. I mean, a pit in a floor is a "visual phenomenon." Illusions are weird magic. Magic itself is weird (I mean, magic missile can hit the target the player wants even if the character can't pinpoint it).

But really I was just trying to explain the argument and that it's not that making a pit is trying to make something actually invisible but disguising it.

[Eriol]

People's RAI can say whatever they want, and you can argue about that specific spell if you wish, but way back on page 1 this poster had it IMO:

There are some illusion spells that explicitly allow you to make subtractive illusions. Disguise self is one such. It could be argued Hallucinatory Terrain strongly implies that ability in some of its example effects. Are these "the exception that proves the rule?"
No "strongly implies about it" IMO: from 5e SRD (http://5e.d20srd.org/srd/spells/hallucinatoryTerrain.htm)

to resemble a swamp, hill, crevasse
There is an illusion spell BESIDES invisibility that by RAW can make "subtractive illusions". Smooth terrain look like a gully. There is no reason I can see by RAW to deny other spells from doing similar subtractive illusions.

Therefore whatever you see as "reasonable" for a 1st-level spell, with the guidance of a "15ft cube" for Silent Image. 15ft pit? Absolutely.

[Tanarii]

There is an illusion spell BESIDES invisibility that by RAW can make "subtractive illusions". Smooth terrain look like a gully. There is no reason I can see by RAW to deny other spells from doing similar subtractive illusions.

Therefore whatever you see as "reasonable" for a 1st-level spell, with the guidance of a "15ft cube" for Silent Image. 15ft pit? Absolutely.
That's a new one. This thing explicitly says you can do something, and this other one doesn't say anything like it, so it can too.

[TaiLiu]

I know a philosopher who, among other things, works with the metaphysics of holes. I've always thought it an exceptionally weird and specific field to work in, but this thread seems to run on a serious disagreement about the ontology of holes, so I guess this is where a metaphysican of holes would really come into handy.

Here's a Stanford Encyclopedia of Philosophy entry on holes. (https://plato.stanford.edu/entries/holes/) It contains some stuff about visual perception that may be of interest to participants in this thread.

[Tanarii]

I know a philosopher who, among other things, works with the metaphysics of holes. I've always thought it an exceptionally weird and specific field to work in, but this thread seems to run on a serious disagreement about the ontology of holes, so I guess this is where a metaphysican of holes would really come into handy.

Here's a Stanford Encyclopedia of Philosophy entry on holes. (https://plato.stanford.edu/entries/holes/) It contains some stuff about visual perception that may be of interest to participants in this thread.
Wow. What a load. Holes are perceived because humans are good are recognizing edges and analyzing shapes. That doesn't mean they exist as some kind of thing.

My favorite piece of nonsense was "Holes are fillable. (You don't necessarily destroy a hole by filling it up. You don't create a new hole by removing the filling.)"
Of course you can destroy (or more commonly repair) a hole by filling it up.

[Santra]

There is an illusion spell BESIDES invisibility that by RAW can make "subtractive illusions". Smooth terrain look like a gully. There is no reason I can see by RAW to deny other spells from doing similar subtractive illusions.

Therefore whatever you see as "reasonable" for a 1st-level spell, with the guidance of a "15ft cube" for Silent Image. 15ft pit? Absolutely.

Yes let's take a level one general illusion spell and give it the same power as a level four specialized spell. I would suggest against this.

As for the question of how illusions are presented I would say they are holograms. The fact it appears the same to everyone and requires you to spend a round physically interacting with it or examining it is very much like a hologram. Not even counting the fact that if it was mind affecting it would require a save.

Personally I don't allow subtractive illusions as doing so quite obviously (to me) makes the spell far more powerful than intended. Optical illusions are a nice idea but if I decided to allow it (I most likely wouldn't) it would only work from one direction and checks to determine it's an illusion would be at advantage as it would be easy to discern on inspection.

[EggKookoo]

Yes let's take a level one general illusion spell and give it the same power as a level four specialized spell. I would suggest against this.

Gameplay balance would be my only reason to disallow it.


As for the question of how illusions are presented I would say they are holograms. The fact it appears the same to everyone and requires you to spend a round physically interacting with it or examining it is very much like a hologram. Not even counting the fact that if it was mind affecting it would require a save.

I don't go in on the hologram interpretation. For one, what do you mean by hologram? Real-world holograms work nothing like magic illusions. Illusions are opaque and react to nearby ambient lighting. Holograms IRL are 2D objects that use EM interference to create the impression of 3D depth. Holograms in movies that work like illusions in D&D are fantasy and can't really be used as a basis for grounding. I mean they're basically magic at that point anyway.

Not requiring a save isn't a lock. A number of spells and effects have no save. Keep in mind that, barring touching it, you cannot tell a silent image from reality without a check. But a check is an active process on the part of the character, which means the character has to have some reason to even think they might be dealing with an illusion to begin with. You don't go around checking everything you run into to see if it's an illusion, right?

"A creature that uses its action to examine the image can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC."

The implication here is that no one, not even a high-level illusionist, can tell an illusion from reality at a glance. You must already have some reason to suspect it's an illusion, and even then you must spend time looking for something -- micro-flaws, perhaps, or some fleeting moment of incongruity or inconsistency. And it's possible you could even fail your check!

"If a creature discerns the illusion for what it is, the creature can see through the image."

So this is the crux of it being partially in your mind. If you encounter an illusion of a door, you can't see through it. If you are tipped off that it's an illusion and succeed in your Int check, or I guess just pass your hand through it, it's revealed to be an illusion and suddenly you can see the room beyond it. But the person next to you who is still under the effects of the illusion can't see through it.

The illusion is affecting two different observers differently at the same time.


Personally I don't allow subtractive illusions as doing so quite obviously (to me) makes the spell far more powerful than intended. Optical illusions are a nice idea but if I decided to allow it (I most likely wouldn't) it would only work from one direction and checks to determine it's an illusion would be at advantage as it would be easy to discern on inspection.

I'm resisting the term "subtractive illusion" as it implies the illusion is making something invisible. The phenomenon of making an apparent hole is really a kind of faked depth trick. Also, I agree that if a player tried to do this I would give advantage to anyone making their Int check when trying to see past it. It's probably harder to pull off.

[Yora]

This had me think of this great early movie effect (https://www.youtube.com/watch?v=vlMFQHbmtpg#t=50s).

The hole is painted on a glas plate in front of the camera.

I wouldn't allow it with silent image, but it should be in the range of major image.

[Tanarii]

Not requiring a save isn't a lock. A number of spells and effects have no save. Keep in mind that, barring touching it, you cannot tell a silent image from reality without a check. But a check is an active process on the part of the character, which means the character has to have some reason to even think they might be dealing with an illusion to begin with. Seeing some thing or some creature physically interact with it is a good starting point IMO.


"If a creature discerns the illusion for what it is, the creature can see through the image."

So this is the crux of it being partially in your mind. If you encounter an illusion of a door, you can't see through it. If you are tipped off that it's an illusion and succeed in your Int check, or I guess just pass your hand through it, it's revealed to be an illusion and suddenly you can see the room beyond it. But the person next to you who is still under the effects of the illusion can't see through it.First off, physical interaction doesn't give the ability to see through an illusion. That just lets you know it's an illusion. It requires an action and a check to see through an illusion.

Second of all, that doesn't mean it's wholly or partially in the mind. It means you've used you mind to impose your logic and reasoning over the magical structure's (aka holograms) affect on your sensory nerves. In the mind and ignoring a magic indirectly affecting your eyes are different things.

But ultimately, irrelevant to the matter at hand. What matters is: can the spell stop you from seeing what is there if it overlays it with nothingness? And the answer is No, because the spell cannot create nothingness to overlay things.


I'm resisting the term "subtractive illusion" as it implies the illusion is making something invisible.If the image overlaps an object, that's exactly what it's done if it erases view of the object by creating some nothingness.


The phenomenon of making an apparent hole is really a kind of faked depth trick.
Which means you're either ignoring the question, or answering it the same as many other people in this thread by saying: No, you cannot create an illusion of a pit in the ground or a door in the wall because the ground / wall can still be seen where the illusion overlaps. But ...

[Pex]

Sometimes a spell is just a spell. Don't overanalyze. Don't look for excuses to make a player idea not work. That doesn't mean a player's idea must always work. It means don't be motivated to have it not work and be disappointed when you can't find a legal loophole so you can self-righteously say you are being a fair DM.

A bad guy sees the pit and tries to jump it. If his ST is 15+ for a 15 ft wide pit he auto succeeds anyway. If he fails he realizes it's not a normal pit when he doesn't fall in. The next guy seeing that checks for it being an illusion. It delays the bad guys for a round or two. That's what it was for. Good job player. It's not a tragedy for a PC's spell to do what it's supposed to do. That's why they use them.

[EggKookoo]

Second of all, that doesn't mean it's wholly or partially in the mind. It means you've used you mind to impose your logic and reasoning over the magical structure's (aka holograms) affect on your sensory nerves. In the mind and ignoring a magic indirectly affecting your eyes are different things.

You and a buddy stand in front of a door. Behind the door is another person with a colored shirt. Of course neither you or your friend can see the person and so can't determine the color of the shirt. You are both told the door is an illusion. You each make Int checks. You succeed, your buddy doesn't. Are you arguing that you now know the color of the shirt worn by the person behind the door (and your friend still doesn't) because you "imposed logic and reasoning" over a magical effect, and somehow that magical effect wasn't affecting your mind?


Which means you're either ignoring the question, or answering it the same as many other people in this thread by saying: No, you cannot create an illusion of a pit in the ground or a door in the wall because the ground / wall can still be seen where the illusion overlaps. But ...

I've explained how that would work numerous times. At this point I have to assume you're deliberately misunderstanding in order to keep your argument going. I can only hope you don't think there's an actual other bathroom on the other side of your bathroom mirror.


Sometimes a spell is just a spell. Don't overanalyze. Don't look for excuses to make a player idea not work. That doesn't mean a player's idea must always work. It means don't be motivated to have it not work and be disappointed when you can't find a legal loophole so you can self-righteously say you are being a fair DM.

A bad guy sees the pit and tries to jump it. If his ST is 15+ for a 15 ft wide pit he auto succeeds anyway. If he fails he realizes it's not a normal pit when he doesn't fall in. The next guy seeing that checks for it being an illusion. It delays the bad guys for a round or two. That's what it was for. Good job player. It's not a tragedy for a PC's spell to do what it's supposed to do. That's why they use them.

Exactly!

[Mehangel]

Yes, of course you can use Silent Image to create the illusionary pit. Naturally, if I were to do it myself, I probably wouldn't ONLY just use a 2d overlay over a flat surface, but would slope the outside of the pit up ever so slightly so to create actual depth to the illusion (even if that depth is only a centimeter or two deep).

Of course even in the right circumstances a simple flat 2d overlay of a circle or square in vantablack (or whatever the world's blackest black is called nowadays) should work. Boom, done.

To me all this nonsense of people insisting that creating an illusionary pit would require Invisibility, or that using Silent Image in this fashion would "reveal the ground below" is just ridiculous.

[Tanarii]

t's not a tragedy for a PC's spell to do what it's supposed to do.
This is not a spell doing what it is supposed to do. It's players attempting to abuse what a spell does by making it cause invisibility, with a spell that is not supposed to do that. Creating holes in the ground and holes in walls is the gateway drug to that.

Good DMs stay ahead of tyrannical players who try to abuse mechanics. :smalltongue: :smallamused:

[PhoenixPhyre]

Yes, of course you can use Silent Image to create the illusionary pit. Naturally, if I were to do it myself, I probably wouldn't ONLY just use a 2d overlay over a flat surface, but would slope the outside of the pit up ever so slightly so to create actual depth to the illusion (even if that depth is only a centimeter or two deep).

Of course even in the right circumstances a simple flat 2d overlay of a circle or square in vantablack (or whatever the world's blackest black is called nowadays) should work. Boom, done.

To me all this nonsense of people insisting that creating an illusionary pit would require Invisibility, or that using Silent Image in this fashion would "reveal the ground below" is just ridiculous.

Exactly. Let's consider a slightly different example:

I should think that it's well accepted you can create an illusion of a 1" thick, 10'x10' stone wall, placed vertically. And even that you can hide behind it and not be seen (unless someone passes their check to see through the illusion). Or that you can place such a "wall" across a passageway or niche in the wall, effectively "closing" the passageway to those that can't see through the illusion. This is a stock usage.

Now do the same thing, just change the colors. Instead of stone wall, make it a perspective drawing of the corridor extending out for 30'. Note that the illusion is still only 1" thick. To someone casually looking at it, it will appear as if the corridor is empty, despite there being other stuff behind it. I see no reason why this is impossible--it's a standard painter's trick, and well within the capacity of a 1st level spell that can replicate a statue perfectly (except for touch).

And if it can do this when placed vertically, it can do so when placed horizontally as well.

Note that the "it can't look different from different angles" argument is just wrong--it can explicitly make a 3D statue that changes as you move around it (ie you can see the back when you're behind it, but not the front). That's no different than changes in perspective for a stereoscopic "flat" image.

And if you're being chased through the enemy's own territory, it's likely that they know there isn't a pit there (granting a free check or advantage on that check). At most the enemy loses an action. That's about the right power level for a 1st level spell.

[Sception]

Silent Image does not create objects or phenomena that look different to different people, tho.

What, in the sense of seeing different sides of it from different angles? It totally does. If you create an illusion of a box, someone standing in front of the box sees the front side of the box, and someine behind the box sees the back side of the box. If you create an illusion of a pit, assuming for a moment the dm allows you to do this, then someone standing in front of the pit sees the back side of the pit, and someone standing behind the pit sees the front side of the pit. Either was, the illusion of three dimensionality shows different images to viewers observing from different perspectives.

Im not saying a dm should definitely allow this, but seeing dufferent perspectives of the same illusion from different sides isn't a reason to prevent it.

[Tanarii]

What, in the sense of seeing different sides of it from different angles? It totally does. If you create an illusion of a box, someone standing in front of the box sees the front side of the box, and someine behind the box sees the back side of the box. If you create an illusion of a pit, assuming for a moment the dm allows you to do this, then someone standing in front of the pit sees the back side of the pit, and someone standing behind the pit sees the front side of the pit. Either was, the illusion of three dimensionality shows different images to viewers observing from different perspectives.
That's like saying a box is perceived differently by different people. Or a pit. It is, but only in that they're standing in different locations so they're receiving slightly different input. But the box or pit itself doesn't change in any way.

(This still isn't a necessary reason to barring it though.)

[Ganymede]

What, in the sense of seeing different sides of it from different angles?

Did you honestly think this is what I was referring to?



Instead of stone wall, make it a perspective drawing of the corridor extending out for 30'. Note that the illusion is still only 1" thick. To someone casually looking at it, it will appear as if the corridor is empty, despite there being other stuff behind it.


You are being awfully generous here with who will recognize this as a real corridor and not as a flat picture wedged up in the corridor.

[PhoenixPhyre]

Did you honestly think this is what I was referring to?



You are being awfully generous here with who will recognize this as a real corridor and not as a flat picture wedged up in the corridor.

That just comes across as a DM looking for ways to deny player's actions. Heck, you could make a 10' cube picture covering the entrance to the corridor and it would be hard to distinguish it from real. Stereoscopic images are a thing, and they're not that hard to do.

[EggKookoo]

Stereoscopic images are a thing, and they're not that hard to do.

Plus... MAGIC!

[Ganymede]

That just comes across as a DM looking for ways to deny player's actions. Heck, you could make a 10' cube picture covering the entrance to the corridor and it would be hard to distinguish it from real. Stereoscopic images are a thing, and they're not that hard to do.

What player actions? What game? We are not enjoying D&D right now and you definitely did not bring snacks. This applies to PCs, NPCs, whatever.


And anyways, as I said before, Silent Image cannot duplicate a science-fictionalized perfection of modern-day technology. It does one thing: it creates things that are only tangible in the sense that they can be seen.

Edit: Meh, I kinda wish my cool Office meme was my last word in this thread, but it has to be this instead.

[Pex]

This is not a spell doing what it is supposed to do. It's players attempting to abuse what a spell does by making it cause invisibility, with a spell that is not supposed to do that. Creating holes in the ground and holes in walls is the gateway drug to that.

Good DMs stay ahead of tyrannical players who try to abuse mechanics. :smalltongue: :smallamused:

It's not invisibility. It's just a hole in the ground.

For a hole in the wall, if the PC knows what's on the other side good for him. If he doesn't it's an illusion of what he thinks is on the other side. The observer's Investigation check includes realizing what he's supposedly seeing isn't supposed to be on the other side among other clues it's an illusion, presuming the observer himself knows what's on the other side. If the observer doesn't either, then it doesn't matter, but there are other clues it's an illusion should the observer bother to check such as touching the wall where the hole looks like it is. Either way it costs the observer's action, delaying him, which was the whole point. Depending on the observer he might not bother to check thinking the hole is real and attempt to go through the hole yet is stopped by the wall but now likely realizing it's an illusion, again delaying the observer as was intended.

[Tanarii]

It's not invisibility. It's just a hole in the ground.
Ultimately, thats the point any DM ruling should probably be made on. If its not a big deal, as a hole in the ground sorta isn't, and you dont think that is outside what the spell should be able to do, then allow it. I'm a bit wary of posters who seem yo think illusions can do things much further outside the boundaries of the spell.

Of course, said DM will have to be prepared for players who want to know why they can't simply make a room appear empty if they can make the ground disappear. IMO for functionality vs balance purposes, if you're going to allow a pit, they best ruling is probably the 2D model, which means you can also make a corridor or room appear empty ... from the outside.

[EggKookoo]

Of course, said DM will have to be prepared for players who want to know why they can't simply make a room appear empty if they can make the ground disappear. IMO for functionality vs balance purposes, if you're going to allow a pit, they best ruling is probably the 2D model, which means you can also make a corridor or room appear empty ... from the outside.

I would allow silent image to make a room appear empty from the outside. Like basically placing the illusion on the entrance, so looking in you see the empty room? My only uncertainty is how to apply the 15 cubic foot limit. Does it mean the false room has to be within those dimensions? Or, since technically the illusion is only on the doorway, can it create the appearance of a room of any size? I lean toward the former mainly for balance reasons.

[Pex]

Ultimately, thats the point any DM ruling should probably be made on. If its not a big deal, as a hole in the ground sorta isn't, and you dont think that is outside what the spell should be able to do, then allow it. I'm a bit wary of posters who seem yo think illusions can do things much further outside the boundaries of the spell.

Of course, said DM will have to be prepared for players who want to know why they can't simply make a room appear empty if they can make the ground disappear. IMO for functionality vs balance purposes, if you're going to allow a pit, they best ruling is probably the 2D model, which means you can also make a corridor or room appear empty ... from the outside.

The problem is really with illusions in general. A DM knows the effect is an illusion and some can't play the NPCs as ignorant of that fact. They have to suspect something's wrong, so DM's look for a fault to exploit to defend why the NPC sees through the illusion. Meanwhile players can't suspect everything they see, so NPC illusions always work at least until the players wasted a few rounds to when something obvious happens to expose the illusion.

[Chronos]

To those saying "it works like a hologram": I've seen some actual real-world holograms that are just a piece of glass, but when you put the piece of glass on top of a table, it really does look like someone cut a hole into the table and put a little statue in the hole. Real-world physics really does allow for that. You can even take a little piece of glass like that, a few inches on a side, and make it look like it's a window into a very large room (I've never seen that particular effect in high enough quality to actually fool a person, but it's in principle possible). But can you make a Minor Illusion or Silent Image of that piece of glass? The piece of glass is an object, and it fits within the size limits... but if you allow that, then you could use Minor Illusion to make an illusion of a mountain (or, if you prefer, an illusion of an illusion of a mountain, but it amounts to the same thing), and that's clearly beyond the power of the spell.

So where exactly does it break down? I don't know. If pressed on the issue, I think that I'd end up ruling that a low-level illusion spell can't produce a reflective surface (or lens or diffraction grating or other optical element) of sufficient quality to produce clear images.

[Mehangel]

The problem is really with illusions in general. A DM knows the effect is an illusion and some can't play the NPCs as ignorant of that fact. They have to suspect something's wrong, so DM's look for a fault to exploit to defend why the NPC sees through the illusion. Meanwhile players can't suspect everything they see, so NPC illusions always work at least until the players wasted a few rounds to when something obvious happens to expose the illusion.

As a DM, this is where I utilize passive investigation checks (it's a thing). I give players who have a passive investigation score that meets the illusion DC notes that their character suspects that X, Y, or Z is an illusion (although they still must investigate by one way or another to see through the illusion). I have my NPC's respond in a similar fashion.

Of course I also find 'The Trickster's Handbook (a 3rd party supplement by Drop Dead Studios) particularly helpful when determining a) what an illusion can or can't do, b) how to properly disbelieve and interact with illusions, c) how illusions can fool even exotic senses such as blind sight, d) how NPC's should react to certain illusions, and many more tips.

[Tanarii]

vs
The problem is really with illusions in general. A DM knows the effect is an illusion and some can't play the NPCs as ignorant of that fact. They have to suspect something's wrong, so DM's look for a fault to exploit to defend why the NPC sees through the illusion. Meanwhile players can't suspect everything they see, so NPC illusions always work at least until the players wasted a few rounds to when something obvious happens to expose the illusion.That's a whole different issue from players wanting illusions to do anything they can imagine, vs me wanting the limits in the spell to actual be actual limits.

[Knaight]

There's also the matter of how nobody is likely looking that hard at it. There's questionable torchlight for lighting, far more pressing things going on, so on and so forth.

[PhoenixPhyre]

There's also the matter of how nobody is likely looking that hard at it. There's questionable torchlight for lighting, far more pressing things going on, so on and so forth.

Exactly. I don't think that most of these illusions would hold up to detailed inspection in a white-room environment--that's why even the product of an expert illusionist (+5 INT, +6 proficiency = DC 19) can be detected by a commoner (on a roll of 19 or 20). But in a dungeon with poor lighting (flickering, not constant, sooty, etc), with people running here and there (or just not paying attention), it can work well enough. For that matter, if you tried to pull the "pit-trap illusion" in broad daylight in the open, I'd give advantage or an auto-success on the check. For someone in unfamiliar territory or hidden in a field of similar pits (or in poor lighting), I'd give disadvantage.

It's not about theoretical cases, it's a matter of practicality. Could someone be fooled? Is it within the realms of the spell? I'd say yes to both. But I might say no to an magician's mirrored box (or require extensive experience with such things and an Intelligence check to pull it off). The role of the DM here is to take the bare words of the spell and make it sensible for the particular scenario, not trying to squish creativity but not just acceding to everything they say either.

[Tanarii]

There's also the matter of how nobody is likely looking that hard at it. There's questionable torchlight for lighting, far more pressing things going on, so on and so forth.
That's a passive perception or investigation check in itself, provided one would normally be required to notice things about a non-illusionary version of the object.

For example in the case of a pit in a dungeon, there often is a passive perception DC associated with noticing the threat before stumbling into it.

[PhoenixPhyre]

That's a passive perception or investigation check in itself, provided one would normally be required to notice things about a non-illusionary version of the object.

For example in the case of a pit in a dungeon, there often is a passive perception DC associated with noticing the threat before stumbling into it.

But those also affect the investigation check to determine if it's an illusion, including whether one happens at all. A busy guard might walk past a "painted empty" hallway with only a glance if it's not part of his regular route or if the light's poor, even if in bright light or a detailed search the illusion would come under close scrutiny and fail quickly.

The DC sets how hard it is to discern that it's an illusion under normal circumstances. Even a less-plausible illusion (under normal circumstances) might pass muster under the right circumstance.