D&D 5E Invisible Objects and Spell Effects under RAW

[jgsugden]

In 5E, invisible creatures are not hidden by default. Even though you're invisible, until you take the hide action, your location is obvious due to your sounds, tracks, etc... We don't all like the rule, but it is there.

What about invisible objects or spell effects? If a cup is made invisible, what needs to be done to detect the presence of it on a table? What does a creature need to do to detect an arcane eye or rope trick portal?

From what I can tell, you fall back to generic rules of setting a perception DC to perceive something that is hard to spot under the RAW - perhaps a DC of somewhere between 15 and 25. Is that how you'd handle the PCs attempting to detect an arcane eye, a rope trick portal, a scrying sensor or an invisibile object on a table?

 

[Phazonfish]

As far as I can tell, unless it impacts something around it (i.e. this table was made invisible, but it was dragged to this corner of the room, so scratches are visible on the floor) you cannot see the presence of something invisible. If you want to find something like this, you would have to touch it, smell it, or (if it gives off noise) hear it. I would never say a player could even possibly detect a scrying sensor with a naked eye.

 

[Oofta]

I rule that there has to be something that can be logically detected. That could be anything from cobwebs to motes of dust to nothing at all.

So there isn't really anything like a standard. I just set the DC based on how I envision the scene.

 

[BigBadDM]

I shake my head at topics like this. why do we have to have rules or 'opinions' on non-existence rules.

1) Don't like a rule, change it. Our group just allows a 'free action' to hide for invisible/heavily obscured creatures. We don't like the rule, so we change it.

2) If there is no rule - such as objects and whatnot. Adjudicate one. That's one of the jobs as a DM.

3) just use common sense. why try to shoehorn a 'fall-back' rule.

4) if they need to know, give them clues. If they don't why bother. Detect Magic is also overlooked.

5) make the story go forward and have fun.

 

[5ekyu]

Invisible means cannot be seen. So if your observer is trying to find it by sight alone, that fails unless there is reason.

As for DC, it would vary as to specifics. Is your invisible mug on a table in the rain? Is it in sn old room with dust? A lot of bugs? Breeze blowing stuff?

It all matters.

 

[Harzel]

I shake my head at topics like this. why do we have to have rules or 'opinions' on non-existence rules.

1) Don't like a rule, change it. Our group just allows a 'free action' to hide for invisible/heavily obscured creatures. We don't like the rule, so we change it.

2) If there is no rule - such as objects and whatnot. Adjudicate one. That's one of the jobs as a DM.

3) just use common sense. why try to shoehorn a 'fall-back' rule.

4) if they need to know, give them clues. If they don't why bother. Detect Magic is also overlooked.

5) make the story go forward and have fun.

Careful with the head shaking - you may injure yourself. OP mentioned how they thought about a situation not covered by the rules and asked for others' thoughts, presumably looking for different/better options. Completely legit; exactly the kind of thing this forum is for.*

* In addition to Survivor threads, which we all know is the main reason the forum exists.

 

[Salthorae]

In 5E, invisible creatures are not hidden by default. Even though you're invisible, until you take the hide action, your location is obvious due to your sounds, tracks, etc... We don't all like the rule, but it is there.

What about invisible objects or spell effects? If a cup is made invisible, what needs to be done to detect the presence of it on a table? What does a creature need to do to detect an arcane eye or rope trick portal?

From what I can tell, you fall back to generic rules of setting a perception DC to perceive something that is hard to spot under the RAW - perhaps a DC of somewhere between 15 and 25. Is that how you'd handle the PCs attempting to detect an arcane eye, a rope trick portal, a scrying sensor or an invisibile object on a table?

It would really depend on the environment the invisible object was in as @5ekyu points out below.

There could be a reason that the PC's could detect the presence of an otherwise invisible object.

For your example of an Arcane Eye. Sure, they're invisible, but they are also moving around potentially. Do they disturb the air when they move (up to you as the DM). If they do, is there smoke in the room when it's moving around? Haze or Fog? Is there just wind noise however faint?

Invisible means cannot be seen. So if your observer is trying to find it by sight alone, that fails unless there is reason.

As for DC, it would vary as to specifics. Is your invisible mug on a table in the rain? Is it in sn old room with dust? A lot of bugs? Breeze blowing stuff?

It all matters.

As for DC... well I'd got back to the long-winded discussion from the Proficiency to AC thread.

There is no call to check if the DM rules that it is impossible to detect. If a DM thinks it's possible, then roll and set a DC. For something like an invisible object but that is somehow interacting with the elements of the room to give some clues as to its location, I'd probably start at 20 or 25 depending on the elements and the size of the object, and then go up from there.

 

[BigBadDM]

Careful with the head shaking - you may injure yourself. OP mentioned how they thought about a situation not covered by the rules and asked for others' thoughts, presumably looking for different/better options.

A little injury is often good for the soul.

But think about this question... if a sword is invisible in the middle of the desert that no one visits, does its existence matter?

If a cup on a table is invisible, does it matter to the story or the plight of the problem? If it does then give clues and well enough of them for them to find the cup. If it doesn't then why bother with the theorem at hand.

Another way to look at it... if the player's NEED to find a secret door to enter the next room (and it is the only way to proceed further), then DCs and skill checks matter not. They find the door.

The way forward should always be attainable for the PCs. If the elements don't matter...then think why they are occurring in the first place.

If someone wants to give the feeling of being watched (as Arcane Eye), just tell the players they feel like they are being watched. Then they can cast true seeing or detect magic to help deduce the problem, if they are so inclined. Give them clues that it appears some force knows where they are going before they get there.

Not everything needs to have a DC roll in the game; especially when there is no interaction with the players.
I shake my head at these things because... well they don't need answers. If they did they would be rules in the book.

But if one wants to go with that route and have everything rolled. Well, just have them do a perception or investigation check. Set the DCs per the baseline guidelines. Easy ->10, Medium -> 15, Hard ->20, etc.

 

[Charlaquin]

From what I can tell, you fall back to generic rules of setting a perception DC to perceive something that is hard to spot under the RAW - perhaps a DC of somewhere between 15 and 25. Is that how you'd handle the PCs attempting to detect an arcane eye, a rope trick portal, a scrying sensor or an invisibile object on a table?

Depends on the player’s approach to attempting to find it. Any attempt to find it that relies purely on sight would fail without a check. But an approach that relies on touch, or on making deductions based on contextual clues might require a check, and in that case hard (15) to nearly impossible (25) depending on the specific approach seems reasonable. Some approaches, such as feeling in exactly the spot it’s in, might succeed without a roll.

 

[jgsugden]

Assume that the invisible items are neither in the "must be found" or "are irrelevant if they are found". They are instead in the "useful if found" category.

Other thoughts? Any RAW we're missing for invisible objects?