Question regarding scenario including Illusion and light.

[ragedeluge]

So we are playing Rappan 5e

Our party traversing down a dark corridor to an opening that is dimly lit. There seems to be a lantern in the next room emitting light. One of the party members goes around the corner and is lit up by a hail of crossbow bolts. He dips back into the corridor suffering damage of course.

This is where the question at hand comes into play. He uses minor illusion to create an illusionary wall on the hallways opening - obscuring the enemy vision from seeing us as they are around that corner readied to attack. My character activated monk's dodge ability went thru the wall grabbed that lantern and ran back toward the corridor tossing the lantern thru the illusionary wall into the corridor to eliminate the enemy's only light source. The issue was the player who cast illusion believes that the light source is blocked from emitting light into the combatant's room via that corridor because of the illusionary wall. The DM claimed that yes they see the wall, they clearly must investigate to identify if it real or not, or interact with it of course, but the lantern behind the illusionary wall in the corridor is still emitting light beyond the illusionary wall since it's an illusion only creating and affecting space within the 5x5 illusionary walls space....

Can minor illusion block light sources from emitting light beyond their threshold? I have an opinion of course but want to hear the input of the community. Need any more info, let me know!

~Rager

[Man_Over_Game]

I think Minor Image isn't strong enough, as a very diverse and versatile cantrip, to be able to block lighting.

The supporting evidence is that once the illusion is revealed, it becomes transparent to that specific person. It was simply "believed" into having a solid appearance, but that has no basis on lighting physics.

[MightyDuck]

If the illusion appears solid, as you'd expect it would, then it must in some way, at least according to real science, be blocking or at least warping the light, as otherwise you would be able to see right through it, the illusion is not tangible but it is opaque. RAW there is no clear answer however I would rule that the illusion can block no magical light since otherwise illusions just wouldn't work, if they don't work where there is light they don't work at all, since the illusion is based on sight which requires light.

[OldSchoolDM]

Sounds like a creative solution to a rough situation. I would rule that until the illusion is interacted with (an investigation check is made) they do not see the light coming through.

Seems like a slippery slope, I'd err on rewarding the players creativity.

[Man_Over_Game]

If the illusion appears solid, as you'd expect it would, then it must in some way, at least according to real science, be blocking or at least warping the light, as otherwise you would be able to see right through it, the illusion is not tangible but it is opaque. RAW there is no clear answer however I would rule that the illusion can block no magical light since otherwise illusions just wouldn't work, if they don't work where there is light they don't work at all, since the illusion is based on sight which requires light.

How would you rule the fact that, if you recognize that it's an illusion, you can see through it? Does it still block light? Does it become this weird quantum substance that only acts real when people believe it is?

[MightyDuck]

How would you rule the fact that, if you recognize that it's an illusion, you can see through it? Does it still block light? Does it become this weird quantum substance that only acts real when people believe it is?

Nothing indicates that you literally see through it you just realize that it's an illusion, it's like seeing through a disguise it's not literal, the illusion doesnt suddenly become see through.

Even if you do run it so that the illusion does suddenly become see through, it's magic, this isn't outside the realms of possibility, doesn't change the way the spell interacts with people who haven't passed and investigation check.

[DrowPiratRobrts]

Nothing indicates that you literally see through it you just realize that it's an illusion, it's like seeing through a disguise it's not literal, the illusion doesnt suddenly become see through.

Even if you do run it so that the illusion does suddenly become see through, it's magic, this isn't outside the realms of possibility, doesn't change the way the spell interacts with people who haven't passed and investigation check.

Not true.

From Minor Illusion: "If a creature discerns the illusion for what it is, the illusion becomes faint to the creature."

[Man_Over_Game]

Nothing indicates that you literally see through it you just realize that it's an illusion, it's like seeing through a disguise it's not literal, the illusion doesnt suddenly become see through.

Even if you do run it so that the illusion does suddenly become see through, it's magic, this isn't outside the realms of possibility, doesn't change the way the spell interacts with people who haven't passed and investigation check.

There was an impressive analysis on this very question on RPG.SE: When Silent Image Is Disbelieved, Is It Transparent? (https://rpg.stackexchange.com/questions/76916/when-silent-image-is-disbelieved-is-it-transparent?rq=1), which hinges on this in the description of Silent Image:


Physical interaction with the image reveals it to be an illusion, because things can pass through it. [...] If a creature discerns the illusion for what it is, the creature can see through the image. There could be two ways you could interpret that last bit:


If a creature figures out it is an illusion, it can literally see through the illusion as if it's transparent.
If a creature figures out it is an illusion, the creature knows it's an illusion.


Most would recognize that the second interpretation is redundant and nonsensical. The only remaining explanation is that the first bullet is true, that the illusion literally becomes transparent for someone who knows it's an illusion.


Even if you do run it so that the illusion does suddenly become see through, it's magic, this isn't outside the realms of possibility, doesn't change the way the spell interacts with people who haven't passed and investigation check.

As for the second part, I normally would say it's 50/50 as to whether the Illusion reacts with light, but due to the fact that it relies on the opinions of creatures for it to appear solid or not, it definitely seems to not block light (although I could see Silent Image react to it to appear real).

However, I'd just assume that's what the Investigation check is for to discern whether an illusion is real or not. Not everyone would be smart enough to make the connection that an object isn't casting a shadow. In the same way, casting a Minor Illusion of a sun does not make a light source.

[DrowPiratRobrts]

There was an impressive analysis on this very question on RPG.SE: When Silent Image Is Disbelieved, Is It Transparent? (https://rpg.stackexchange.com/questions/76916/when-silent-image-is-disbelieved-is-it-transparent?rq=1), which hinges on this in the description of Silent Image:

There could be two ways you could interpret that last bit:


If a creature figures out it is an illusion, it can literally see through the illusion as if it's transparent.
If a creature figures out it is an illusion, the creature knows it's an illusion.


Most would recognize that the second interpretation is redundant and nonsensical. The only remaining explanation is that the first bullet is true, that the illusion literally becomes transparent for someone who knows it's an illusion.



As for the second part, I normally would say it's 50/50 as to whether the Illusion reacts with light, but due to the fact that it relies on the opinions of creatures for it to appear solid or not, it definitely seems to not block light (although I could see Silent Image react to it to appear real).

However, I'd just assume that's what the Investigation check is for to discern whether an illusion is real or not. Not everyone would be smart enough to make the connection that an object isn't casting a shadow. In the same way, casting a Minor Illusion of a sun does not make a light source.


Could the OP please clarify if we're discussing Minor Illusion the cantrip or Silent Image the 1st Level Spell? They're worded differently. I know you said Minor Illusion in your OP, but it's only a 5ft cube, so did it really create a wall from floor to ceiling, or did you mean to say Silent Image?

[Ganymede]

In order to prevent giving myself a migraine, I just roll every potential inconsistency in the illusion as part of the investigation check. When you pass your investigation check, that's when you notice that illusory reflections are wrong and that illusory walls aren't blocking light.

[Derpy]

I think I would rule that as soon as the player tossed the lantern through the minor illusion cantrip, there was a physical interaction with it; ergo the spell effect "Physical interaction with the image reveals it to be an illusion, because things can pass through it." takes effect, making the blocking of the light a moot point. Because, of course, "If a creature discerns the illusion for what it is, the illusion becomes faint to the creature." To be honest, him coming through it in the first place is a physical interaction and would render it faint, IMO.

I think I would allow it to block light on its own, provided 1, it blocked the whole corridor, and 2, it was not known as an illusion. Once known as an illusion I would no longer allow it to block light, though if a player argued their point cleverly enough I might have it be dim illumination instead of bright.

[Mjolnirbear]

I think I would rule that as soon as the player tossed the lantern through the minor illusion cantrip, there was a physical interaction with it; ergo the spell effect "Physical interaction with the image reveals it to be an illusion, because things can pass through it." takes effect, making the blocking of the light a moot point. Because, of course, "If a creature discerns the illusion for what it is, the illusion becomes faint to the creature." To be honest, him coming through it in the first place is a physical interaction and would render it faint, IMO.

I think I would allow it to block light on its own, provided 1, it blocked the whole corridor, and 2, it was not known as an illusion. Once known as an illusion I would no longer allow it to block light, though if a player argued their point cleverly enough I might have it be dim illumination instead of bright.

Whereas I interpret physical interaction to mean "the people who don't know it's illusion touch the illusion or see someone/thing touch it". It seems more logical to me that the disruption comes from feeling for a wall and not getting a wall, not that matter passing through the spell disrupts the spell.

The monk knows it's an illusion. No enemies are present to see this. In my game the wall remains unless there was an enemy present to see the monk run through. Or even sees the lantern go through.

I tried the light argument on an old DM and he game what is, to me, an excellent argument. If Minor Illusion can create light, obstruct it, or cause darkness, what's the point of having the Light cantrip be separate, or Darkness being a second-level spell? It is already a very strong spell. It doesn't need to be buffed at the expense of two other spells.

[Derpy]

The monk knows it's an illusion. No enemies are present to see this. In my game the wall remains unless there was an enemy present to see the monk run through. Or even sees the lantern go through.


You mean the enemies who were, presumably, ready to shoot him a second time weren't looking and didn't just see a wall pop up, and then him go through it? And then him throw a lantern through it? A bunch of really lucky x-bow shots that lit up the party member the first he popped in then.

[Mjolnirbear]

You mean the enemies who were, presumably, ready to shoot him a second time weren't looking and didn't just see a wall pop up, and then him go through it? And then him throw a lantern through it? A bunch of really lucky x-bow shots that lit up the party member the first he popped in then.

I understood OP's description of around the corner to mean out of sight, at least partly because the question makes no sense at all if the enemies watched the casting then watched the monk go out and then in, and the light question wouldn't matter at all.

If as you say the monsters watched a creature walk through a wall that wasn't there's six seconds ago, then the illusion was wasted. Not even monks are so fast that they can't be seen moving.

Now if the illusion was a cloud of fog or smoke, the monk moving through it, in my games anyways, wouldn't matter, because fog isn't solid. This illusion would require the enemy to touch the cloud and either not start coughing due to smoke or not feel cold and damp.

In my games, it's not "solids disrupt the spell" but "senses not getting feedback that should be there and thus the creature realises its an illusion".

[Derpy]

I understood OP's description of around the corner to mean out of sight, at least partly because the question makes no sense at all if the enemies watched the casting then watched the monk go out and then in, and the light question wouldn't matter at all.

If as you say the monsters watched a creature walk through a wall that wasn't there's six seconds ago, then the illusion was wasted. Not even monks are so fast that they can't be seen moving.

Now if the illusion was a cloud of fog or smoke, the monk moving through it, in my games anyways, wouldn't matter, because fog isn't solid. This illusion would require the enemy to touch the cloud and either not start coughing due to smoke or not feel cold and damp.

In my games, it's not "solids disrupt the spell" but "senses not getting feedback that should be there and thus the creature realises its an illusion".

First off, OP stated they put the illusion "On the hallways opening."

If you're around the corner the illusion makes even less sense; you're popping out into an area with enemies who are still watching (presumably) where you came from, getting to where their lantern is, and attempting to throw it around a corner? If the lantern got around the corner no problem, it's around a corner and no longer lighting the room, worst case another party member puts it out or puts a blanket over it, the illusion not needed; it's not hiding you before you jump out, it's not needed to prevent the light, it's accomplishing nothing. The more I think about this situation the less sense it makes to me TBH. It seems like a case of the party overthinking it or pushing boundaries, instead of thinking the situation through.

I agree with you about fog or smoke. It makes sense to see someone moving through it. It makes no sense for someone to see someone else move through an object and go "huh, i haven't touched it but it still must be solid despite evidence to the contrary." A small thing, like a cloak brushing against it might go unnoticed, but jumping through a cantrip is another thing entirely.

[Man_Over_Game]

Now if the illusion was a cloud of fog or smoke, the monk moving through it, in my games anyways, wouldn't matter, because fog isn't solid. This illusion would require the enemy to touch the cloud and either not start coughing due to smoke or not feel cold and damp.

In my games, it's not "solids disrupt the spell" but "senses not getting feedback that should be there and thus the creature realises its an illusion".

Doesn't that contradict with your advice with your DM friend?


I tried the light argument on an old DM and he game what is, to me, an excellent argument. If Minor Illusion can create light, obstruct it, or cause darkness, what's the point of having the Light cantrip be separate, or Darkness being a second-level spell? It is already a very strong spell. It doesn't need to be buffed at the expense of two other spells.

Fog Cloud is an actual level 1 spell.

Additionally, Minor Illusion says it can create an object, where Silent Image says it can create virtually any visible phenomenon.

Lastly, the DMG states "For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone..."

[Aimeryan]

Regarding Minor Illusion; the text says that it can create an image but cannot create light. An image can be formed two ways: via the manipulation of existing light or via the creation of light.

Most images are of the former; for example, sunlight hits the leaf of a plant, some light is absorbed, some is reflected. Most plant leaves would reflect most light in the green part of the spectrum and absorb most light in the red and blue part of the spectrum, which means we see the leaf as being green. We see the shape of the leaf because where the leaf does not exist it cannot manipulate the light.

Some images are of the latter - computer screens work this way.

Minor Illusion clearly does not work by the latter method - no light is created as per the text. So this means its the former? Well, there is another possibility - the image is mental only. That is, the brain is telling them that they can see whatever the illusion is meant to be, but no sensory input is actually occurring. However, lets presume it is not mental (a saving throw would usually be expected in that case); this means the illusionary magic must be manipulating light, like most solid objects do.

So what about the question of the opening post? Well, it should be recognised that even seemingly continous solid objects do let some light through - this is more obvious with thin objects like a shirt than something like a wall. The illusion would not be very convincing at all if a significant portion of the light coming from behind it was allowed to pass through it unmodified - unless it was perhaps an image of a shirt. My judgement here would be that the illusion would function in the same way as what it is an illusion of; an illusion of thick stone wall should block light similar to a thick stone wall. It must be manipulating the light anyhow in order to create the image.

~~~

What about that pesky 'if recognised, go faint' clause? One possibility is that the magical manipulation can be negated once known about. For example, perhaps it is like reading the sentence 'uijt jt bo jmmvtjpo' once you know the letters have just been shifted by one character forward - the manipulation still exists but you are able to reverse it and parse the sentence correctly.

Of course, if we go down the 'its all mental' road, then its simply the creature fighting against this mental manipulation once it realises it is present.

[Mjolnirbear]

Doesn't that contradict with your advice with your DM friend?

Fog Cloud is an actual level 1 spell.

Additionally, Minor Illusion says it can create an object, where Silent Image says it can create virtually any visible phenomenon.

Lastly, the DMG states "For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone..."

Good point, although Smoke Cloud is not a spell. Regardless, neither (as it turns out, and thanks to you for my TIL) are valid uses of Minor Illusion.

My comments on fog are therefore only really relevant to non-Minor-Illusion spells that *can* reproduce fog. At any rate, it was off-topic, only included to frame my thought process. Please consider it in an academic light since it's not relevant to OP's post.

[Mjolnirbear]

Regarding Minor Illusion; the text says that it can create an image but cannot create light. An image can be formed two ways: via the manipulation of existing light or via the creation of light.

Most images are of the former; for example, sunlight hits the leaf of a plant, some light is absorbed, some is reflected. Most plant leaves would reflect most light in the green part of the spectrum and absorb most light in the red and blue part of the spectrum, which means we see the leaf as being green. We see the shape of the leaf because where the leaf does not exist it cannot manipulate the light.

Some images are of the latter - computer screens work this way.

Minor Illusion clearly does not work by the latter method - no light is created as per the text. So this means its the former? Well, there is another possibility - the image is mental only. That is, the brain is telling them that they can see whatever the illusion is meant to be, but no sensory input is actually occurring. However, lets presume it is not mental (a saving throw would usually be expected in that case); this means the illusionary magic must be manipulating light, like most solid objects do.

So what about the question of the opening post? Well, it should be recognised that even seemingly continous solid objects do let some light through - this is more obvious with thin objects like a shirt than something like a wall. The illusion would not be very convincing at all if a significant portion of the light coming from behind it was allowed to pass through it unmodified - unless it was perhaps an image of a shirt. My judgement here would be that the illusion would function in the same way as what it is an illusion of; an illusion of thick stone wall should block light similar to a thick stone wall. It must be manipulating the light anyhow in order to create the image.

~~~

What about that pesky 'if recognised, go faint' clause? One possibility is that the magical manipulation can be negated once known about. For example, perhaps it is like reading the sentence 'uijt jt bo jmmvtjpo' once you know the letters have just been shifted by one character forward - the manipulation still exists but you are able to reverse it and parse the sentence correctly.

Of course, if we go down the 'its all mental' road, then its simply the creature fighting against this mental manipulation once it realises it is present.

Explaining and expanding magic using science is a risky proposition. A clever player can use rulings based on science (and also pseudo-science) to deduce corollaries like "if X is possible because Y, then it follows Z". At that point spells like Control Weather can become terrifying, since weather contains vast energy potential and storms can have the power of an atomic bomb.

Also, 'can shocking grasp electrify the lake and kill all enemies in it and by the way free fried food' becomes a question. Or 'can ray of frost freeze the pond solid' or 'what's the PH of acid splash'.

I'm not saying don't do it. I'm saying be aware of the issues that will come up. If you play with actual scientists this could become terrifying. But players with half-remembered highschool physics will be worse, and more plentiful.

To me, easiest by far is to say 'no because it's magic not science'.

[Tanarii]

Couple of things here:
- Does your DM rule that physical interaction just means they know it's an illusion and act accordingly, or it becomes transparent as if they made a Investigatin check. The "goes faint" clause can either be considered a sub-clause of both, or just the investigation check.
- does your DM rule that any physical interaction applies to anyone that sees it? Or only the creature doing the interaction?

If the DM rules that physical interaction makes it go faint, and applies to anyone that sees it, when the monk went though the illusionary wall, it became faint to all the opponents that saw them do that. So the question about the lamp is moot.

(Personally I rule the physical interaction is a global thing for anyone that saw it, but the going faint clause only applies to an action to make an investigation check. This powers up illusions, but is balanced out by being strict on interpreting what an illusion spell can do in terms of "object", "creature", or especially "visual phenomena".)

As far as the illusion blocking light goes, I personally rule that it does not, but you can't see the source of the light. In other words, the radius of bright or dim light doesn't change. It's not the most physics-of-magic ruling, but makes playing the game easy.

[Aimeryan]

Explaining and expanding magic using science is a risky proposition. A clever player can use rulings based on science (and also pseudo-science) to deduce corollaries like "if X is possible because Y, then it follows Z". At that point spells like Control Weather can become terrifying, since weather contains vast energy potential and storms can have the power of an atomic bomb.

Also, 'can shocking grasp electrify the lake and kill all enemies in it and by the way free fried food' becomes a question. Or 'can ray of frost freeze the pond solid' or 'what's the PH of acid splash'.

I'm not saying don't do it. I'm saying be aware of the issues that will come up. If you play with actual scientists this could become terrifying. But players with half-remembered highschool physics will be worse, and more plentiful.

To me, easiest by far is to say 'no because it's magic not science'.

You have to use cause and effect to some degree either way, otherwise you have difficult doing anything not literally provided for in the book. Unless, everything that happens is magic? Walking, talking, eating, breathing...

I cannot recall anything in the book saying that if you are in an environment with no air you cannot breath, but presumably that is how you would rule by default? There may be exceptions for some reason, but the player can reasonably assume "science" is involved in normal play without the book having to spell it out directly.

Shocking Grasp deals lightning damage; lightning is an electrical discharge and electricity can travel through water (presuming this is not ultra-pure water, which lake water is almost certainly not). If brought up as being relevant, the answer to "Can Shocking Grasp electrify the lake since it deals lightning damage?" I would have to either say "No, because X", "No, but I am not telling you why", or "Yes". Those are my options as I see them. The "No, because X" can simply be that X = magic, that is fine, however it would be a ruling, not the default. The default would presume "science".

~~~

As for the opening question, it does not spell out every literal possibility involved with illusions - most of it you are going to have to use "science" (which is really just a synonym for logic, here). I laid out the logic as I see it in why I would rule that Minor Image would block light to the same degree as the image it is presenting - it would not be very convincing otherwise. I also presented the mechanism by which it may be achieved (manipulation of light to present an image) - although note, it wouldn't really matter whatever reasoning you gave as long as your players are happy with it.

[JoeJ]

Shocking Grasp deals lightning damage; lightning is an electrical discharge and electricity can travel through water (presuming this is not ultra-pure water, which lake water is almost certainly not). If brought up as being relevant, the answer to "Can Shocking Grasp electrify the lake since it deals lightning damage?" I would have to either say "No, because X", "No, but I am not telling you why", or "Yes". Those are my options as I see them. The "No, because X" can simply be that X = magic, that is fine, however it would be a ruling, not the default. The default would presume "science".

No, the default is that spells do what the text says they do and nothing more. By default, lightning is not electricity. In fact, there's nothing anywhere in the rules that indicates electricity (as modern science understands that term) or electrons exist at all.



As for the opening question, it does not spell out every literal possibility involved with illusions - most of it you are going to have to use "science" (which is really just a synonym for logic, here). I laid out the logic as I see it in why I would rule that Minor Image would block light to the same degree as the image it is presenting - it would not be very convincing otherwise. I also presented the mechanism by which it may be achieved (manipulation of light to present an image) - although note, it wouldn't really matter whatever reasoning you gave as long as your players are happy with it.

One other possibility is that it does not block light, but viewers think that it does. That is, it's literally an illusion.

[PhoenixPhyre]

No, the default is that spells do what the text says they do and nothing more. By default, lightning is not electricity. In fact, there's nothing anywhere in the rules that indicates electricity (as modern science understands that term) or electrons exist at all.

Right. The fundamental underpinnings of physics in D&D realms are completely different than ours. Only the vaguest surface phenomena are the same, but for unrelated reasons. If you try to go beyond pre-modern science (so "things dropped will fall", but you don't know why), you're on shaky ground.

For example, my setting has only one type of matter (compressed anima) that can be "flavored" or "aspected" in different ways. It's fundamentally the same thing, just with different filters. This is the same stuff as souls are made of. A fire spell doesn't create "fire", it simply imposes a temporary aspect of fire on a region of anima. Same with electricity.

[Aimeryan]

No, the default is that spells do what the text says they do and nothing more. By default, lightning is not electricity. In fact, there's nothing anywhere in the rules that indicates electricity (as modern science understands that term) or electrons exist at all.



One other possibility is that it does not block light, but viewers think that it does. That is, it's literally an illusion.

The literal definition of lightning is an electrical discharge - unless we are saying the language isn't English anymore and lightning means something else? If they said it did umbongo damage you would have a point.

I mentioned the possibility of it all being mental (an illusion need not be mental), however, those tend to invoke Will saves which makes it less plausible. Also, it tends to have other implications (for example, subtractive omni-angle illusions).

Illusions in 5e are very poorly defined, having but a bare skeleton of a structure and requiring the DM to rule out the muscle and flesh of the spell. They end up being very DM-dependent.

[JoeJ]

The literal definition of lightning is an electrical discharge - unless we are saying the language isn't English anymore and lightning means something else? If they said it did umbongo damage you would have a point.

I mentioned the possibility of it all being mental (an illusion need not be mental), however, those tend to invoke Will saves which makes it less plausible. Also, it tends to have other implications (for example, subtractive omni-angle illusions).

Illusions in 5e are very poorly defined, having but a bare skeleton of a structure and requiring the DM to rule out the muscle and flesh of the spell. They end up being very DM-dependent.

What is this "electrical" you speak of?

And I don't mean necessarily mental, but perceptual. Consider a 3d movie. You are presented with a 2d image on a flat surface, but your vision is fooled into seeing a 3d object in front of the screen. Maybe the spell is produces a very sophisticated optical illusion.

[Ganymede]

What is this "electrical" you speak of?

Both the facetious answer and the helpful answer here are exactly the same: Ask your DM.

The rules themselves are not fully comprehensive. They cover only the most common/expected scenarios one might encounter while playing this game, and everything else is covered by DM adjudication. The lack of rules on electricity does not imply that electricity does not exist any more than the lack of rules on scurvy does not imply that people won't get sick if they go for a long time without Vitamin C; the lack of rules here just means that the DM has to deal with it.

[Mellack]

Shocking grasp would have to be a very different form of electricity than we have in our world. In D&D world it is easier to damage a person encased in full metal armor with it. In our world such a person would be essentially immune to electrical damage. In our world metal is a much better conductor than flesh, and electricity flows through the metal to ground. You can see videos of people in essentially full suits of chain playing around with very high voltage without harm. That D&D acts the opposite is evidence that their physics must be very different.

[Aimeryan]

Shocking grasp would have to be a very different form of electricity than we have in our world. In D&D world it is easier to damage a person encased in full metal armor with it. In our world such a person would be essentially immune to electrical damage. In our world metal is a much better conductor than flesh, and electricity flows through the metal to ground. You can see videos of people in essentially full suits of chain playing around with very high voltage without harm. That D&D acts the opposite is evidence that their physics must be very different.

My understanding of the metal armour shocking grasp advantage is that the metal is conducting the electricity to the person easier than say clothing or a rubber shield would. The spell/book doesn't cover the possibility of you being grounded (https://en.wikipedia.org/wiki/Ground_(electricity)) by the metal armour. If someone pointed out that the metal armour was in contact with the ground I would still give advantage but I would lower the damage considerably and change the type to fire (the metal would get hot).

[JoeJ]

My understanding of the metal armour shocking grasp advantage is that the metal is conducting the electricity to the person easier than say clothing or a rubber shield would. The spell/book doesn't cover the possibility of you being grounded (https://en.wikipedia.org/wiki/Ground_(electricity)) by the metal armour. If someone pointed out that the metal armour was in contact with the ground I would still give advantage but I would lower the damage considerably and change the type to fire (the metal would get hot).

Plate armor would normally be in contact with the ground.

I wouldn't change the spell for any reason related to real world physics. (I might give it a significantly different effect if cast on a human boy named Billy Batson, but that's obviously not RAW.)

[Mellack]

My understanding of the metal armour shocking grasp advantage is that the metal is conducting the electricity to the person easier than say clothing or a rubber shield would. The spell/book doesn't cover the possibility of you being grounded (https://en.wikipedia.org/wiki/Ground_(electricity)) by the metal armour. If someone pointed out that the metal armour was in contact with the ground I would still give advantage but I would lower the damage considerably and change the type to fire (the metal would get hot).

Every standard form of metal armor includes leather or cloth under it. It wouldn't realistically help cause damage at all, only protect. Electricians who work on high-power lines wear suits with a metal weave in them as protection. Even without padding, very little electricity would leave the far easier path of the metal.
Which is why I say D&D shocking grasp can't be the same as our electricity. It doesn't follow the same rules our electricity does. (I am not suggesting the spell be changed, I am saying it quickly falls apart when you try to apply real-world physics to D&D.)

[ad_hoc]

Jeremy Crawford stated clearly that illusions don't block light (unless they involve shadow matter and such).

I think it was in a recent Dragon+ Q&A.

Also, don't bring 'science' into it. It's magic.

[Aimeryan]

Plate armor would normally be in contact with the ground.

Agreed. Not all metal armour is plate armour, however - see chain mail, brestplates, etc.


I wouldn't change the spell for any reason related to real world physics. (I might give it a significantly different effect if cast on a human boy named Billy Batson, but that's obviously not RAW.)

You aren't changing the spell, just the resulting effect it has on the person. This has precedence; the Invulnerability spell makes you immune to all damage - Shocking Grasp usually deals damage, but this changes the resulting effect it has. Plate armour would do the same.

Either way, as Ganymede explained, the rules are not comprehensive so you end up using lots of things that are not RAW just by playing the game.


Every standard form of metal armor includes leather or cloth under it.

This is true, however, other forms of armour would be more resistant (and also have clothing underneath) - so relative to that the metal armour is less resistant which is conveyed as advantage.


It wouldn't realistically help cause damage at all, only protect. Electricians who work on high-power lines wear suits with a metal weave in them as protection. Even without padding, very little electricity would leave the far easier path of the metal.

This is only true if the resulting metal ends up grounding the person, as explained before. Otherwise, the current would follow the least resistant path - the metal - until there was no more metal and only person. The rules don't cover grounding - they aren't comprehensive. That doesn't mean it doesn't exist.

[Mellack]

This is only true if the resulting metal ends up grounding the person, as explained before. Otherwise, the current would follow the least resistant path - the metal - until there was no more metal and only person. The rules don't cover grounding - they aren't comprehensive. That doesn't mean it doesn't exist.

Even if the metal is not grounded, it would protect the vitals. The electricity would only travel through the person from where the metal stops to the ground. So instead of taking it through your vital chest area, only your legs would get some burns. It should do less damage than to a non-metal armored person in that case. It also shouldn't be any easier to score a hit, either way you need to contact the person. I think the game would grind to a halt if you insist on making ruling based on non D&D world physics for every interaction.

[JoeJ]

You aren't changing the spell, just the resulting effect it has on the person. This has precedence; the Invulnerability spell makes you immune to all damage - Shocking Grasp usually deals damage, but this changes the resulting effect it has. Plate armour would do the same.

Whatever you want to call it, I wouldn't use electricity in our world as a model for fantasy lightning. Lightning is the weapon of the storm god, the power of dragons, and a tool of wizards. Making shocking grasp work the way electricity does in our world does not provide any benefit that I can see. It just creates questions about blue dragon's breath and the lightning bolt spell, which are also lightning and do not act like real world electricity.

[Tanarii]

D&d is infamous for taking the piss with real world physics, while not actually using it correctly all all. Attempting to make spells do a logical or actual physics result is a losing bet.

But making it do something based on a laymans misunderstanding of pop science is what D&D was founded on.

The primary reason not to allow spells to be all extra is because thats giving them more power than intended. But if someone wants to blow a spell slot for an obviously lesser effect that provides a clever solution, its worth considering allowing it.

Personally i rule strictly, but thats just because IMX most players naturally try to push limits to gain mechanical power. If youre specific players arent like that, or you just dont care, no need to keep a cap on things.