D&D 5E Minor Illusion question

[Thyrwyn]

No, but Minor Illusion states that it cannot generate light. TV screens generate light.

I read the spell limitation to apply to illumination, not light as defined by physics.

If the spell meant light-waves, then any attempt to apply physics to the spell is impossible. It creates no matter, so it cannot reflect anything; it creates no energy, so it cannot be perceived.

 

[Tony Vargas]

So what you'll really be saying is that you can't see light directly from the torch but you can see light from the torch that goes and bounces off a wall first. So WALLS can see light directly from the torch but your eyes can't. And... why? Nothing about that is in the spell. Further, light that then bounces off the walls then has what effect on the image? None of this makes sense.

Of course not, because you're trying to make a modern understanding of light conform to a magical one (or vice versa... or something like that).

Consider this. Not so very long ago, before Newton wrote the Principia, reasonably well educated 'natural philosophers' believed that we see, not by receiving light wavicles being re-emitted by surfaces that just absorbed them in some quantum-mechanical shooting gallery, nor even by receiving light waves propagated through the circumambient luminiferous ether, but by actually emitting rays from our eyes - your actual 'gaze' - and seeing what those rays contacted (with or without the idea that they bounce back to your eyes). You didn't need light to see because you needed a source of photons, but because light repelled darkness, and darkness was opaque to your gaze (unless, of course, you have darkvision).

Now, crazy and unsupportable a theory as that may be to modern experimentation, it happens to neatly answer the minor illusion question. It illusion around the torch doesn't block the light of the torch, because it's not real, the light of the torch chases the darkness of the room into shadows and corners, like always, and people who enter the room can see just fine. They just don't see what's chasing all the darkness away, which is a little weird - but, hey, they live in a magical universe, a little weird really isn't - but they do see a box, because their gaze falls on the box and is deceived by the magic of the illusion. When they save, their gaze can penetrate the illusion, and the box no longer looks solid.

(In addition, this crazy old theory obviously explains why you can 'feel someone watching you,' because their gaze is physically touching you. Light, darkness, and the gaze of a living creature are all essentially real things. Also works for rationalizing the behavior of gaze weapons. )

 

[jodyjohnson]

Which also explains heat vision, x-ray vision, and the blinding gaze of David Lo Pan.

 

[Tony Vargas]

The history of science is a goldmine of ideas, even if you're not playing a Son of Ether in Mage: the Ascension.

 

[Tormyr]

I'm not sure why you're insisting on comparing this to darkness, it is nothing like it. The 5x5x5 cube being one. Moving is another. Yes, you can block a torch that happens to be in a 5x5x5 cube, but ray of frost can just as easily put that torch out, does that make ray of frost more powerful than Darkness?

Put simply, if you use the spell to make an image of an opaque object, like a box, then the image will appear to be an opaque object, like a box, which means you won't see light through it. If you did see light through it, then it would look nothing like an opaque box.

The spell clearly is intended and worded to allow you to make opaque objects of a quality that is not trivial to determine isn't real. This means that it has to be opaque to light or it will be trivial to determine that your weirdly lit shadowless or colored shadow projecting object is not at all the object it is attempted to simulate.

It is irrelevant if the torch is outside the box, inside the box or if the light is meeting the box directly from the light source or bouncing off another object before meeting the box. To appear as if it is an opaque object, IT HAS TO BLOCK LIGHT. If it isn't blocking light, it will not appear to be an opaque object.

Yes, the object blocking light for some people and not blocking it for others seems weird, but if you think about it, it is exactly as weird as any other spell effect that only works on some people in an area and not others. There are many many spells that have exactly the same type of weirdness going on. That is magic for ya.

Putting out a torch versus blocking light that is being generated is comparing apples to oranges. The comparison with darkness works on one level if minor illusion is allowed to block the light. The spell's description does not give it this ability.

Making an illusion of an opaque object does not mean that the illusion is actually opaque. Especially since more than one creature can view it differently simultaneously. Then the question becomes, "What is the 'true' state of the illusion, and what does it do to appear as a real object? In my opinion, the "true" state of the illusion, what it really looks like, is what it looks like after a creature passes its Intelligence (Investigation) check or has truesight. According to the spell description, the illusion becomes faint to the creature. As for what makes it look like a real object at first, that explanation can work in several different ways which generally start and end with: magic. The optical illusion analogy is just one way of thing about it.

Where this becomes a useful question though is what effect the illusion has on other stuff. If the true state of the illusion is a faint image, then it does not stop anything but the smallest amount of light.

The illusion of an opaque object does not need to be opaque itself. An illusion that is truly opaque and did not just appear to be opaque means that it would block the light. Then it gets into why it is different for those that pass their ability check and not for the others. An illusion that is actually blocking the light that is investigated successfully by an 8 Intelligence barbarian and becomes faint to it means that the barbarian with no magical ability or aptitude has altered the spell. It has altered the spell because the opaque illusion was actually opaque and no longer is for the barbarian, and light now comes through the illusion just for the barbarian. This also means that the barbarian can alter the spell from any distance away as long as it can see the illusion.

It seems to be far more straightforward to view the illusion as truly being faint and the viewer's initial take on it is to misinterpret what it is seeing as a solid object. Back to our example, the light level in the room is the same for everyone. The only difference that occurs when the creature passes their check is they go from thinking, "Oh, a box on the wall that seems to be casting shadows without glowing," to ,"oh, it is an illusion covering a torch."

Out of interest, what is another spell that works on some people in an area and not others?

 

[Warmaster Horus]

And here, on Page 5, it becomes very apparent why I NEVER play illusionists.

 

[Saeviomagy]

The main issue I have with the illusory box not blocking light is that if that is the case, illusions would merely require a perception check to defeat, because not having a shadow isn't something that requires interaction to notice.
That badly weakens the school of illusion which in my experience has always needed all the help it can get.
Also, I'm not to worried about cantrips putting out lights, because there are multiple ones that can do it. The whole cheapo devils sight, darkness combo requires you to be fighting where only one light source is present.. And your opponents can't see in the dark, which has historically been pretty rare in d&d.

 

[Sword of Spirit]

How about this:

D&D Physics: You don't see objects because they reflect light. You see objects just because objects are inherently seeable. In certain (supernatural) situations shadows can exist without anything casting them, and objects can fail to cast shadows. The presence of light is a prerequisite for seeing objects, but is not the cause of their perceptibility.

Simple (non phantasmal) Visual Illusions: Illusions create an unreal, seeable object. The presence of the object can be seen by any creature, regardless of distance, and the object has no effect on the passage of light or shadows (unless the spell specifies otherwise). It is not a mental effect, it is an unreal object that quasi-exists in a certain location. Unreal objects have less, well reality! than real objects. If a creature realizes that an object is unreal, the creature's greater reality allows them to see through the unreal object.

 

[Kalshane]

The main issue I have with the illusory box not blocking light is that if that is the case, illusions would merely require a perception check to defeat, because not having a shadow isn't something that requires interaction to notice.
That badly weakens the school of illusion which in my experience has always needed all the help it can get.
Also, I'm not to worried about cantrips putting out lights, because there are multiple ones that can do it. The whole cheapo devils sight, darkness combo requires you to be fighting where only one light source is present.. And your opponents can't see in the dark, which has historically been pretty rare in d&d.

Darkness isn't a Cantrip, though. It's a 2nd level spell. And Devil's Sight requires at least two levels in Warlock. That's a lot different than a Cantrip that can be done at-will, and is easily picked up via a single class level, a feat or even being the proper race.

My view is you're using the weakest possible Illusion spell, with severe restrictions on what it can achieve in the text. I have zero problem with effects outside it's limited scope being impossible, and attempting them results in the weirdness of "This normal looking box on the wall seems to be shedding torch light" that makes it easier to recognize as an illusion. It certainly makes a lot more sense than a room that is dark or light to its inhabitants based on whether or not they believe the box is actually there.

 

[Staffan]

We're talking about a world where gravity is binary (either 0G or 1G), and magically propelled ships that leave the atmosphere bring along enough air in their gravity envelope to last their crew for months.

We're also talking about a world where you can use permanent magic items to create machines that break the laws of thermodynamics in all kinds of ways.

Discussing what D&D illusions can do by using modern concepts of physics seems to me a losing proposition.