D&D 5E How Would this Surprise Example Play Out?

[The Crimson Binome]

If the archer was hiding in the trees surrounding this clearing then he can be hidden while still being able to see creatures in the clearing. He can shoot from hidden, and that shot will resolve as a shot from hidden; he's shooting through the foliage rather than running into the open clearing and then shooting!

Yes, that is a possible interpretation. The DM can say that the archer remains hidden, even though the PCs have direct line of sight to him, because the PCs didn't specifically say that they're checking the trees for snipers. Or even if they say they're specifically checking the trees for snipers, the DM might say that this requires a check, which they can fail. And the DM can further say that, since the PCs aren't specifically looking at where the archer is hidden, he has advantage on the attack roll, and they aren't alerted to his presence until the arrow hits them (or goes whizzing past). That is a totally valid interpretation.

The alternative interpretation is that the archer must break cover in order to gain a clear line to his target, so the PCs automatically see him, and therefore his attack roll is not made with advantage. This interpretation is equally supported.

 

[Arial Black]

Yes, that is a possible interpretation. The DM can say that the archer remains hidden, even though the PCs have direct line of sight to him, because the PCs didn't specifically say that they're checking the trees for snipers. Or even if they say they're specifically checking the trees for snipers, the DM might say that this requires a check, which they can fail. And the DM can further say that, since the PCs aren't specifically looking at where the archer is hidden, he has advantage on the attack roll, and they aren't alerted to his presence until the arrow hits them (or goes whizzing past). That is a totally valid interpretation.

The alternative interpretation is that the archer must break cover in order to gain a clear line to his target, so the PCs automatically see him, and therefore his attack roll is not made with advantage. This interpretation is equally supported.

Both interpretations are supported because both are feasible situations.

It is not that each table has to choose which interpretation to use and stick to.

It is that whether or not the sniper needs to break cover in order to get a shot, depends on the type of cover: foliage? can shoot through the leaves without breaking cover. Sniper rifle? Can fire through an open window without having to jump through the window first! Has to open a door and move 40 feet to stab you? Not so much.

Although I think there would be general agreement about which cover allows you to shoot through it, the next examples may be more divisive: I would allow a hidden creature to quickly stand up from the cover of a low wall, and his first shot to be from hidden. I would allow a hidden archer to lean around a corner and his first shot would be from hidden. But in both cases I would only allow that at the beginning of combat. During a long combat where baddies are firing over a low wall, you know that they are there and you know they are going to pop up and shoot. But if you are not in combat (initiative/combat rounds), the first time someone breaks cover to shoot, you had no idea they were there and you weren't ready for it when they do. For me, that first shot would have advantage for attacking from hidden, even if you were un-surprised. YMMV.

 

[ClearlyTough69]

Also, 'cover' can be one-way. If you are hiding in the tree branches, you can easily have cover re: being hidden from your target, but you can still observe and shoot at your target from that position. You are still hidden for that first shot, but you are no longer hidden after that first shot resolves because that attack is what gave you away.

How about obscurement, rather than cover: can that be one way? I certainly think so; otherwise you'd never be able to hide in dense foliage and shoot from it in an ambush.

But this does subtly change the rules for obscurement caused by foliage or some other sort of screening effect, as opposed to dim light or darkness. I house rule that you have to be within five feet of the edge of a heavily obscured area to be able to see into a neighbouring unobscured area as though it were lightly obscured; likewise, you have to be within ten feet of the edge of a lightly obscured area to be able to see into a neighbouring unobscured area as though it were unobscured [EDIT: DELETE lightly obscured].

How do other people handle this?

 

[Arial Black]

How about obscurement, rather than cover: can that be one way? I certainly think so; otherwise you'd never be able to hide in dense foliage and shoot from it in an ambush.

But this does subtly change the rules for obscurement caused by foliage or some other sort of screening effect, as opposed to dim light or darkness. I house rule that you have to be within five feet of the edge of a heavily obscured area to be able to see into a neighbouring unobscured area as though it were lightly obscured; likewise, you have to be within ten feet of the edge of a lightly obscured area to be able to see into a neighbouring unobscured area as though it were lightly obscured.

How do other people handle this?

That makes sense.

That is how fencing masks work. In the sport of fencing, part of the safety equipment is the facemask. The main part of the mask is a close-set wire mesh. When wearing it, your eyes are close to the mesh, and because you are not perfectly still and because the brain can make an accurate picture from the light that does come through the mesh, you can see just as well as if you weren't wearing a mask at all. But no-one else can see your face, because it is obscured by the mask.

Even hard cover kind of works like that. If you are standing against a low wall then you have some cover from the enemy archers 100 feet away. But they don't get cover from that wall against your arrows.

 

[Hriston]

How about obscurement, rather than cover: can that be one way? I certainly think so; otherwise you'd never be able to hide in dense foliage and shoot from it in an ambush.

But this does subtly change the rules for obscurement caused by foliage or some other sort of screening effect, as opposed to dim light or darkness. I house rule that you have to be within five feet of the edge of a heavily obscured area to be able to see into a neighbouring unobscured area as though it were lightly obscured; likewise, you have to be within ten feet of the edge of a lightly obscured area to be able to see into a neighbouring unobscured area as though it were lightly obscured.

How do other people handle this?

I find the vision rules (post errata) to be fairly straightforward. For the purpose of determining what a creature can see, I make no distinction based on whether the viewer is in an obscured area, or whether the area being seen into is obscured by fog, foliage, lighting conditions, or some other factor. A heavily obscured area, for example, blocks vision of things within that area, but has no effect on vision of things outside that area. I find this makes adjudication of what can be seen very simple.

 

[Hriston]

There are five goblins. Each of them roll Stealth checks: 8, 9, 10, 11, and 12. There are five PCs. Between them, they have passive Perceptions of 10 and 11.

First, to elaborate on what you've established here, the five goblins aren't currently being seen, at least not clearly, because otherwise they wouldn't be able to hide as you are having them do here. Also, the PCs aren't currently engaged in any exploration tasks that would keep their passive Perception scores from being consulted, or in a marching rank that would keep them from being able to notice the hiding goblins.

I see this going one of two ways:

1) The four goblins who rolled 11 and under on their Stealth checks are seen but the one who rolled 12 isn't; he has surprise and is the only person who can go in Round 1.

In the DEX/WIS contest, the hider wins a tie, so the goblins who roll 11 and 12 are both successful in remaining hidden. The one who rolls a 10 is noticed by the PCs with a score of 11, but isn't seen unless the circumstance that allowed it to be unseen in the fire place has changed somehow, otherwise none of the goblins are seen. Also, none of the PCs are surprised because each PC notices at least two goblins.

Or:

2) None of the goblins get surprise since four out of five are seen, though the one that rolled 12 is hidden and will get Advantage as normal.

Since they are all still unseen, they can all attack with advantage provided they can remain unseen while they attack, e.g. if they were hiding in a heavily obscured area.