D&D 5E Reminders on Illusions

Lanefan

Victoria Rules
Where does the stuff about reflections come from?
From reading, and taking literally, that an illusion cannot generate light.

Having the illusion cast a reflection means it's generating light. In particular, consider a situation where an observer can see the illusion but not the light source (maybe the light's around a corner, or the viewer is indoors but the illusion is outside "reflecting" the sun).
An illusion can't create light (unless specified), but it does presumably respond to ambient lighting levels (i.e. an image cast in a completely dark room is invisible, but if you shine a light upon it, it will be revealed, and will appear to be being lit from that direction). That pretty much has to be the case for it to work at all and not be immediately obvious as an illusion.
My point exactly. Not allowing illusions to generate light ends up being a huge nerf.

Easy enough to rule that an illusion cannot generate light beyond what the surrounding environment is already providing - this allows for reflections but prevents it being used as a Light spell. Still doesn't answer my glowing-sword example, though, as to me that's something I feel I should be able to do - have the glow, even if it's limited to dim, be visible even if the room is otherwise dark in order to attract attention.
So, if the object can appear to be lit differently depending upon the ambient light (i.e. it has the appearance of reflecting that light), and if you can see different parts of it as you walk around it, at what point does a reflective surface become too reflective to work that way?
If the illusionist could see both the reflecting surface and the viewer, and have it react properly (check definitely required!), I'd allow an illusion to function as a mirror. But if the caster couldn't see one or the other the mirror effect wouldn't be possible.
 

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Lanefan

Victoria Rules
The inability to create light is part of how the spell works. Still waiting for a source on the reflection thing.
You probably won't get an official source. The reflection thing was a conclusion I drew from my own taken-literally reading of the RAW as presented in the OP. I doubt the official types have even given it a thought.
 

Lanefan

Victoria Rules
The problem with the discussion on light is the illusion has to alter light in its area of effect. Light is what your eyes sense so saying it can't create light means in effect it can't create an image. With this in mind I think the correct interpretation is the illusion alters the perception of light and it acts on the individuals mind to do this, not their eyes

The way I rule this for minor illusion and silent image is they cause or modify the perception of light specifically related to the illusion itself in their own area of effect.

For example you make an illusion of a 5 foot black box around a torch on the wall, then the box itself covers the wall, if you specify it is a completely dark and opaque 5 foot box then that 5 foot area is dark and looks like a black inky 5 foot cube. The area right outside the box is still in bright light from the torch, although anyone looking at it would not understand where the light is coming from. If you touch the box it turns "dim" and you see through it to the torch underneath and can see anything else in that 5 foot area as if it is in bright light.
This is well thought out.
Another example - If you are in completely dark area and create an image of a lit torch, everyone sees the torch, but the torch casts no light at all. Even if you create it right on top of a creature and know it is an illusion, you still can't see any part of that creature without darkvision or some comparable ability. In this respect it does not cast "light" even in the space it occupies but you would still "see" the torch itself. If you instead made a 5' bright sphere (i.e. a miniature sun), again everyone would see the sun but it would cast no light outside its space and anyone who recognized it for an illusion could "see" through it but would not see anything inside it without darkvision because there is no light there.
The main use of this type of illusion would be to briefly mess up darkvision, as the viewers' eyes would need to adjust.
 

MarkB

Legend
From reading, and taking literally, that an illusion cannot generate light.

Having the illusion cast a reflection means it's generating light. In particular, consider a situation where an observer can see the illusion but not the light source (maybe the light's around a corner, or the viewer is indoors but the illusion is outside "reflecting" the sun).

My point exactly. Not allowing illusions to generate light ends up being a huge nerf.

Easy enough to rule that an illusion cannot generate light beyond what the surrounding environment is already providing - this allows for reflections but prevents it being used as a Light spell. Still doesn't answer my glowing-sword example, though, as to me that's something I feel I should be able to do - have the glow, even if it's limited to dim, be visible even if the room is otherwise dark in order to attract attention.

If the illusionist could see both the reflecting surface and the viewer, and have it react properly (check definitely required!), I'd allow an illusion to function as a mirror. But if the caster couldn't see one or the other the mirror effect wouldn't be possible.
And then you get onto weird cases like: If a human spellcaster creates a silent image in a well-lit room and then someone turns the light out, what does that image look like to a dwarf or elf? The human has no direct experience of darkvision, and has no idea what a pitch-dark scene looks like to those who do possess such senses.
 

You probably won't get an official source. The reflection thing was a conclusion I drew from my own taken-literally reading of the RAW as presented in the OP. I doubt the official types have even given it a thought.
I don't think that with easy read (natural language) approach they gave much thought on this. This is severely limiting illusions for nothing as anyone with a passive perception of 15 or more would notice such a details in a world where illusions exists. People, especially adventurers, would be on the look out for such clues.
 
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Lanefan

Victoria Rules
And then you get onto weird cases like: If a human spellcaster creates a silent image in a well-lit room and then someone turns the light out, what does that image look like to a dwarf or elf? The human has no direct experience of darkvision, and has no idea what a pitch-dark scene looks like to those who do possess such senses.
Indeed, which is why I'd rule an illusion cast by someone without darkvision would do nothing in the dark...unless the illusion could be made to glow with normal light, in which case everyone could see it.
 

Lanefan

Victoria Rules
I don't think that with easy read (natural language) approach they gave much thought on this. This is severely limiting illusions for nothing as anyone with a passive perception of 15 or more would notice such a details in a world where illusions exists. People, especially adventurers, would be on the look out for such clues.
That they didn't give much thought on illusions is all too obvious and has been for a while; and illusion rulings are one instance where a rather great deal of thought and care is required.

I think I'd find playing an illusionist in 5e to be incredibly frustrating.
 

pming

Legend
Hiya!

Any spell/type of spell that requires that much 'explanation' is failing horribly at conveying what the spell can do. IMNSHO, of course.

When it comes to describing what an Illusion can do... "short and vague" is the best approach. :) This is why in MY 5e Campaign, I use a more 'simplistic' approach to them.

For me, if I were to write it down into words:

Minor Illusion: You can make an illusion of a non-moving thing.
Silent Image: You can make an illusion of a moving or non-moving thing, but without sound.
Phantasmal Force: You can make a creature perceive something as real, but only in their mind.
Major Illusion: Like Minor Illusion/Phantasmal Force, but perceivable to those around, not just in someone's mind.
Programmed Illusion: As Major Illusion, but it can be set to be 'triggered' by something (time duration, someone entering area, etc).

Any "notes" that cover all:
  • Illusions are only capable of working on something with a "mind" (so no skeletons, golems, etc).
  • Illusions can affect any sense or senses.
  • If someone 'sees through an illusion', others get an INT or WIS Save with Advantage (the NEXT round) if the original person can describe the illusion to them. If the person fails, they do NOT get another save until after a Short Rest.
  • Invisibility is NOT AN ILLUSION! It is an ENCHANTMENT in my game.

I MUCH prefer these sort of 'description' for Illusions. The main reason is that Illusions are like "Stealth" or "Perception"...there are just FAR too many ways of "doing them" that there is no way to write down anything specific, and the more one tries to 'codify' the "can" and "can not" part...the more conflict that is likely to occur between Players and DM's.

Sometimes "Less is more". With illusions, DEFINITELY the case! :)

^_^

Paul L. Ming
 

That they didn't give much thought on illusions is all too obvious and has been for a while; and illusion rulings are one instance where a rather great deal of thought and care is required.

I think I'd find playing an illusionist in 5e to be incredibly frustrating.
We had an illusionist a few years ago. It was very frustrating. So we "modified" them so that illusions would be good again. But this is homebrew. As they are written, they fail to make illusions powerful and dangerous.
 

Dausuul

Legend
Having the illusion cast a reflection means it's generating light.
That is far from the only interpretation. In fact, I think it's extremely strained. If we were talking about a real, non-illusory mirror, nobody would say that it "generates" light; it reflects light. Put a mirror in a dark closed room with no light sources, the room remains dark.

With the illusion, there are two possibilities about what's going on: It interacts with physical light rays, or it's all in the viewer's mind. In the former case, the illusion is reflecting light rays just as a real object would (which is how it can be seen at all) and "it can't generate light" does not preclude this.

In the latter case, since the illusion is not actually interacting with light in any way, "it can't generate light" must refer to the viewer's perception--the illusion cannot delude the viewer into thinking that it is producing light. But, again, it must be able to delude the viewer into thinking that it is reflecting light, or it would not be visible at all.

Either way, there is a strong argument that the illusion can show a reflection. One does not have to interpret it that way, but it's entirely consistent with the text of the spells, and therefore the "no reflections" claim has no business in an OP that claims to be offering reminders on the illusion rules.
 

ECMO3

Hero
From reading, and taking literally, that an illusion cannot generate light.

Having the illusion cast a reflection means it's generating light. In particular, consider a situation where an observer can see the illusion but not the light source (maybe the light's around a corner, or the viewer is indoors but the illusion is outside "reflecting" the sun).
The problem with this is your eyes only see light.

When you look outside your window at the green leaves, what is actually happening is light from the sun is hitting the leaves. The light from the sun is "white" light and includes all visible colors as well as infrared and ultraviolet. All that light hits those leaves and the green portion is reflected into your eyes while the other colors are absorbed by the leaf. What you see is a reflection of the green portion of the sunlight.

When you look at yourself in a mirror the same thing is happening, light from a source (sunlight, lamp etc) is reflecting off of you. The colors that reflect off of you hit the mirror, the other colors are absorbed by your body. This light that is reflected off of you then reflects again off of you to the mirror, and back to the eyes of whoever is looking at the mirror. A mirror reflects all colors of visible light, so unlike your body or clothes or the leaves it does not absorb any of it and what you "see" is the exact same colors that hit the mirror to start with. Because it is a polished flat surface the reflection is clear and it maintains spacial coherency, unlike a leaf or something that is textured.

So bottom line, if the illusion does not create light and does not reflect light, then it can not be "seen" by your eyes.

Edit: This post assumes the leaves are green, I realize many of us are looking at red or brown leaves right now.
 


gator001

Villager
Read the description of the spell again. It's not minor illusion that can't create sensory effects, it is the image created by minor illusion that can't.

Specifically is says: If you create an image of an object—such as a chair, muddy footprints, or a small chest—it must be no larger than a 5-foot cube. The image can't create sound, light, smell, or any other sensory effect.
How do you see an illusion?
 



Laurefindel

Legend
physics-bending magic is always hard to explain with rational physical explanations (or optical in this case).

The very nature of a (visual) illusion is to fool our sense of sight. Our sense of sight is made possible by light reaching our eyes, either by emanation or reflection (or refraction). A visual illusion can be seen, therefore it must be producing whatever it needs to produce in order to be seen and fulfill its role as an illusion. So in order to explain illusions realistically, they need to produce light. By the same logic, they can also absorb light, otherwise we'd be seeing through them.

But I believe that the spirit of the rule here is that a minor illusion cannot produce illumination, and that is simple enough to comprehend and implement. If you create an illusory (lit) candle in darkness, it won't produce illumination in a 5 foot-radius like a real lit candle would. As a matter of fact; it won't be seen by anyone that do not have darkvision. An illusory torch will not increase a dimly lit area to bright light either. Both will appear "lit" to an observer who can see them but the lack of illumination will be mind-boggling. Something will feel wrong, enough to warrant a Int save at the very least, if not an auto-detection as if interacted with.

The contrary is also true; realistically speaking, an illusion needs to block light in order to be opaque, but it cannot block "illumination". An illusory rock over a candle will obfuscate the candle, but it won't block the light produced by the flame that illuminates the area around it (well I guess a 5-foot illusion could cover the 5-foot illumination area of a candle). So you'd be stuck with a glowing rock; which can be weird enough to warrant an Int save or prompt some kind of interaction (which in turn will betray its illusory nature).
 
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jgsugden

Legend
A couple feedback items to people on this thread:

* Sage Advice comes from the people that approve the rules, and usually goes to clarifying what is intended. You can approach them as you like, but they are meant to convey the intent of the RAW.

* Real world physics are fine to consider until they contradict the rules. This is a fantasy game and involves fantasy elements. If the written rules for illusions create a situation that differs from the real world way that light and vision work, it is reality, not the rules of the game, that is wrong - because otherwise we'd be invalidating the entire rule set because none of the fantasy is reality.

* Some of the things I presented note an ambiguity, and the consensus that I have seen. Whether Siletn Image can create light or not is going to end up being up to the DM.

* The "reflection" parts are discussed by Crawford during the interview I mentioned. Go find that and listen to it if you want more clarity.
 

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