D&D 5E Rogue's Cunning Action to Hide: In Combat??

[Rabulias]

A target can benefit from cover only when an attack or other effect originates on the opposite side of the cover.

I read that to mean that if I am shooting at a target from 10 feet behind a low wall, the cover counts for my attacks against them, and their attacks against me.

If I am adjacent to that low wall (or an arrow slit, as has been discussed) so that I can get the release point of my arrow beyond the cover, then it does not apply for my attacks against the target, but it still provides cover for the target's attacks against me.

 

[Oofta]

This is why the rogue makes a Dexterity (Stealth) roll and the target(s) use passive Perception or make an active Wisdom (Perception) roll to spot the rogue. Maybe the rogue is not as quiet as they hoped as they prepared to peek out and shoot. Maybe the top of their bow stuck out too far and the target caught a glimpse of it. Maybe the rogue's shadow on the opposite wall betrayed their motion to attack from the high right side. Or maybe the target is more distracted at that moment and misses seeing any clues to the rogue's intent. It's not an automatic thing - there is a skill check or contest involved, and the rogue might blow it.

@Lyxen As a counterpoint, what about the Help action in combat? Do you allow an ally using the Help action in combat to grant advantage? Even if they do it round after round to the same opponent?

Or maybe I just run it slightly different than you do and don't want to have this kind of thing decided by the roll of the dice every time. Being stealthy doesn't make you invisible.

 

[Charlaquin]

What Jeremy Crawford says cannot be any more clear than that

"A creature provides half cover, regardless of that creature's size."

I think your interpretation of Jeremy’s tweet is correct. I just think Jeremy’s tweet is wrong.

 

[Charlaquin]

No, my answer was with regards to the Gelatinous Cube, a halfling needs a creature one size larger than him, but he could hide behind another halfling after being targeted by a reduce spell.

Huh. I always wondered why they phrased it that way instead of “a Medium or larger creature.” Don’t know why I never considered magically altered size.

That would also seem to imply a lightfoot druid in the form of a Tiny beast could hide behind a Small creature (and one in the form of a Large beast would need a Huge or larger creature to hide behind). Neat!

 

[Plaguescarred]

I think your interpretation of Jeremy’s tweet is correct. I just think Jeremy’s tweet is wrong.

His tweet isn't wrong in respect to Cover rules as they don't mention anything about creature's size specifically.

 

[Ovinomancer]

It's a consistent baseline to use but not the only possible baseline to use. As long as you use that same baseline for all calculations you're going to at least roughly get a fair comparison.

No, you kinda aren't, which is my point. His choices inflate the use of multiple dice -- the more your dice roll, the more free increase in output you get. The difference goes from +1/2 a point at level 1 sneak attack to +5 points at level 20. That's a free boost because of his choice of rounding. Again, if I compare a d12 to 3d4, the averages due to TM's method are 6 vs 9, respectively. Using 3d4 gets you 3 free points on the same baseline.

I mean, your larger point is very much true -- if you're using the same baseline, and the baseline is fair, then it doesn't really matter if the baseline is accurate -- it's precise and that's enough. However, if your method introduces biases, then you should be aware of how that works and how it affects comparisons, and knowing that TM's method inflates, strongly, the use of multiple dice can be very telling, especially when your choice of PC is using around 14 dice (not counting the double counting due to crits).

 

[Ovinomancer]

Cover usually work both ways. An arrow slit is certainly an exception by design, it's not a 2-way straight cut through a wall, it specifically designed to shoot outward and protect inward. I would not use such cover as proof that a cover doesn't work both ways as it's more the exception that proves the rule.

Cover in 5e is determined by tracing lines from a corner of your square (your choice) to all corners of a single square the target occupies (your choice if more than one). If 1 or 2 of those lines is obscured by an obstacle (or creature), they have 1/2 cover. If 3 or 4 lines are blocked, and the attack could still reach the target (there's at least some line from somewhere in your square to somewhere in their square) it's 3/4 cover. If there is no line from anywhere in your square to anywhere in theirs that is not obstructed, it's full cover.

 

[Ovinomancer]

Huh. I always wondered why they phrased it that way instead of “a Medium or larger creature.” Don’t know why I never considered magically altered size.

That would also seem to imply a lightfoot druid in the form of a Tiny beast could hide behind a Small creature (and one in the form of a Large beast would need a Huge or larger creature to hide behind). Neat!

Don't you lose your racial traits if you're polymorphed? Maybe if reduced...

 

[Plaguescarred]

Cover in 5e is determined by tracing lines from a corner of your square (your choice) to all corners of a single square the target occupies (your choice if more than one). If 1 or 2 of those lines is obscured by an obstacle (or creature), they have 1/2 cover. If 3 or 4 lines are blocked, and the attack could still reach the target (there's at least some line from somewhere in your square to somewhere in their square) it's 3/4 cover. If there is no line from anywhere in your square to anywhere in theirs that is not obstructed, it's full cover.

That's only if using variant grid rules.

 

[Plaguescarred]

The DMG also offer additional grid play rules for determining Line of Sight that makes very easy for enemies to see a creature hiding behind a pillar or another creature. Moving just a little can let you notice it.

Line of Sight: To precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If at least one such line doesn't pass through or touch an object or effect that blocks vision - such as a stone wall, a thick curtain, or a dense cloud of dog - then there is line of sight.