[MC-2404] Stepping down while sneaking allows falling off of blocks Created: 06/Nov/12  Updated: 04/Oct/21  Resolved: 29/Jun/20

Status: Resolved
Project: Minecraft: Java Edition
Component/s: None
Affects Version/s: Minecraft 1.4.2, Minecraft 1.4.7, Snapshot 13w07a, Minecraft 1.6.1, Minecraft 1.6.2, Minecraft 1.7.2, Minecraft 1.7.4, Minecraft 14w03b, Minecraft 1.7.9, Minecraft 14w18b, Minecraft 1.8-pre1, Minecraft 1.8.2-pre6, Minecraft 15w44b, Minecraft 15w45a, Minecraft 1.8.9, Minecraft 15w51b, Minecraft 16w02a, Minecraft 16w04a, Minecraft 16w05b, Minecraft 16w06a, Minecraft 16w07a, Minecraft 16w07b, Minecraft 1.9 Pre-Release 1, Minecraft 1.9 Pre-Release 3, Minecraft 1.9 Pre-Release 4, Minecraft 1.9, Minecraft 1.9.1 Pre-Release 3, Minecraft 1.9.1, Minecraft 1.9.2, Minecraft 1.9.4, Minecraft 16w20a, Minecraft 1.10.2, Minecraft 16w32a, Minecraft 16w32b, Minecraft 16w33a, Minecraft 16w35a, Minecraft 16w36a, Minecraft 16w42a, 1.15.2, 20w16a, 20w19a, 1.16 Pre-release 4
Fix Version/s: 20w27a

Type: Bug
Reporter: Brandon Bourgeois Assignee: [Mojang] Panda
Resolution: Fixed Votes: 24
Labels: sneaking

Attachments: PNG File 2014-05-07_16.33.29.png     PNG File 2014-05-07_16.33.55.png     PNG File 2014-05-07_16.34.29.png     PNG File 2014-05-07_22.32.34.png     PNG File 2014-05-07_22.34.59.png     PNG File 2015-02-12_09.51.22.png     PNG File 2020-06-11_18.00.08.png    
Issue Links:
Duplicate
is duplicated by MC-9133 Falling down half blocks even with sh... Resolved
is duplicated by MC-9966 When there is a redstone repeater nex... Resolved
is duplicated by MC-26112 While crouching on a slab,player fall... Resolved
is duplicated by MC-54729 Not being able to fall at the edge of... Resolved
is duplicated by MC-114515 Falling off stairs while crouched Resolved
is duplicated by MC-144814 It is possible to fall of a block whi... Resolved
is duplicated by MC-162455 crouching doesn't prevent you from fa... Resolved
is duplicated by MC-169270 Fall off block while crouching Resolved
is duplicated by MC-177320 Crouching then moving to soul sand al... Resolved
is duplicated by MC-183346 Crouching does not help on slabs and ... Resolved
is duplicated by MC-197165 Player sneaking over cake allows them... Resolved
Relates
relates to MCPE-88723 Stepping down while sneaking allows f... Open
relates to MC-197647 Players cannot jump off the edge of b... Resolved
relates to MC-193662 Player flying in creative slightly ab... Resolved
relates to MC-199326 Unable to escape block bound box when... Resolved
relates to MC-200282 Players with knockback resistance can... Resolved
relates to MC-201874 Sneaking off the edge of a block with... Resolved
relates to MC-2334 Sneaking on shorter than full blocks ... Resolved
CHK:
Confirmation Status: Confirmed
Game Mode: Survival
Category:
Player
Mojang Priority: Important

 Description   

While sneaking, if one steps down a half-block, they can fall off of the blocks being snuck on. For instance, descending stairway while sneaking while walking at a diagonal will result in falling off of the stairs, instead of remaining on them as would happen on a flat path.

This happens with any block that can be stepped down from while sneaking, including stairs, slabs, redstone repeaters, trapdoors, and snow. Repeaters in particular are annoying for redstone lines built without any kind of walls next to them.

Oddly, carpet is not affected, despite it having a slightly raised hitbox.



 Comments   
Comment by Napero [ 04/Oct/21 ]

This bugfix brought more problems and side effects than good things.

Comment by FireSkorpion [ 29/Dec/20 ]

The fix of this has led to players not being able to step down a block while sneaking with a block above the head (MC-209925).
You now need to mine the two blocks above, and to the side of the player to jump a full block up and then fall two, onto the block you wanted to get to.

It probably conflicts with the fix of this bug and will therefore probably from now on be seen as intended behaviour.

Comment by [Mod] markderickson [ 08/Jul/20 ]

Hi there!

The fix of this bug has likely led to a new bug, MC-193662. Players in creative mode flying above blocks while holding the sneak key down are restrained to that block. I'm pretty sure that the fix for this has led to the newer bug, but I could be wrong (it could be other changes in the snapshot that led to this).

Comment by Dobbi [ 11/Jun/20 ]

Can confirm it affects 1.16 Pre-Release 4

Comment by Pedro Suarez [ 02/Jun/20 ]

Bruh, I died like this in my hardcore world, but I didn't think this was a bug . It was on a end city ship.

Comment by Alugia [ 16/Apr/20 ]

Confirmed in 20w16a

Comment by [Mojang] Grum (Erik Broes) [ 03/Nov/16 ]

This is WAI.

If you while you are 'falling' down a step keep trying to walk off the side, you will move a bit in the air causing you to fall of the block.

Comment by Alexander [ 21/Oct/16 ]

Confirmed for 16w42a

Comment by Fenhl (Max Dominik Weber) [ 24/May/16 ]

Affects 16w20a.

Comment by Fenhl (Max Dominik Weber) [ 04/Apr/16 ]

Affects 1.9.2.

Comment by Fenhl (Max Dominik Weber) [ 17/Mar/16 ]

Affects 1.9.1-pre3.

Comment by Fenhl (Max Dominik Weber) [ 27/Feb/16 ]

Affects 1.9-pre4.

Comment by Fenhl (Max Dominik Weber) [ 25/Feb/16 ]

Affects 1.9-pre3.

Comment by Fenhl (Max Dominik Weber) [ 17/Feb/16 ]

Affects 1.9-pre1.

Comment by Fenhl (Max Dominik Weber) [ 16/Feb/16 ]

Affects 16w07b.

Comment by Fenhl (Max Dominik Weber) [ 15/Feb/16 ]

Affects 16w07a.

Comment by Fenhl (Max Dominik Weber) [ 10/Feb/16 ]

Affects 16w06a.

Comment by Fenhl (Max Dominik Weber) [ 09/Feb/16 ]

Affects 16w05b.

Comment by Fenhl (Max Dominik Weber) [ 29/Jan/16 ]

Affects 16w04a.

Comment by Fenhl (Max Dominik Weber) [ 14/Jan/16 ]

Affects 16w02a.

Comment by Fenhl (Max Dominik Weber) [ 17/Dec/15 ]

Affects 15w51b.

Comment by jonathan2520 [ 12/Feb/15 ]

torabi: That's not really going anywhere. You can pull the entire game apart like that. Why don't you simply fall over, given the way your legs move? Right, because you only fall over when you die, moments before vanishing in a puff of smoke. Not that you'd normally see that in case of your own body because your arm (the only part of your body you can see in first person) disappears. Makes sense.

Simplified bounding volumes are much more reasonable than air barriers where you couldn't possibly grab something at any level. Sneaking basically activates simple AI that helps you not to fall off and shouldn't change physics drastically. So far the only deviation is that it makes you stop faster, at a point where you can usually stop almost as fast.

Okay, enough pedantry. There are relevant arguments up here somewhere. I have nothing to add.

Comment by [Mod] Torabi [ 12/Feb/15 ]

jonathan2520, it's already possible to float in mid-air, sneaking just makes it easier to get there. As shown in my screenshot, no part of my body is actually touching the stairs, and yet I'm considered standing on them. If you sneak straight towards the edge of the stairs, you cannot fall. The world is already "permeated by invisible barriers".

KingSupernova, your opinion has been noted, and there's no need to repeat it. If someone at Mojang directs us to close it, then we will. Or they can do it themselves. Or they can leave it open, or they can change the behavior. It's their decision to make, not yours.

Comment by KingSupernova [ 12/Feb/15 ]

This is intended. It's your fault for moving yourself while falling. This report should be closed.

Comment by KingSupernova [ 02/Feb/15 ]

This is not actually a bug. What happens is that the game looks at where you are trying to fall to and sees that it is less than a block down, so it lets you fall. As you are falling, you move yourself slightly to the side with the movement keys, and you go off the edge of the stairs. This is no more a bug then the fact that lava kills you. If you don't want to fall off, don't walk towards the edge.

Comment by jonathan2520 [ 07/Oct/14 ]

NekoAmps: The most basic extension would put you to a dead stop almost everywhere in mid-air. If you add a special case, the world is now permeated by invisible barriers, dwarfing invisible fence extensions. It plain makes no sense. If you add another special case to only make it work at very low speeds, descending while hiding from other players is still a much bigger pain than it already is. You can't win.

The movement algorithm iteratively checks whether your prospective bounding box has too much empty space below it. If so, it's slowly moved back to your previous position. Whoever coded it looks confused, but it looks like it should work in the end. Interaction with other adjustments might be responsible for those times when sneaking fails.

Comment by Neko Alexander Perdomo [ 07/Oct/14 ]

In short, what would be ugly about holding the player back in midair? I think that would be the best action taken, if any is.
Does MC look at blocks, the potential drop, or something else when deciding to keep a player from dropping? I imagine this would be easier to patch for the second option.

Comment by jonathan2520 [ 07/Oct/14 ]

I believe this is more of a fundamentally quirky feature than a bug.

Sneaking only keeps you on top of a block if you're touching it. It also allows you to drop a small distance, which is exactly what you're doing when walking down stairs (or half slabs or the like). During the drop it doesn't do anything for you, so you can fall off at that time.

All of the potential fixes have significant side effects:

  • Don't allow any drops at all.
  • Hold the player back even if they're in mid-air.
  • Glue the player to the ground on small drops.
  • Add a special case.

The bottom line is that something will have to change in a big way. What do you want to break to fix this? I can't rule it out but it won't be pretty.

Comment by S P [ 24/Aug/14 ]

Confirmed in 1.8-pre1

Comment by Kumasasa [ 07/May/14 ]

Yes thanks, that's what we found out in the meantime too.

Comment by Brandon Bourgeois [ 07/May/14 ]

Still an issue. Photos added to illustrate. If you sneak directly toward the side of a stair you will not fall, but continue holding the sneak key and then move a half block down you will fall off the edge.

Comment by Kumasasa [ 07/May/14 ]

Maybe the player is not onGround for a short amount of time while "falling" from the upper stair to the lower stair and for that short moment the sneak function doesn't work anymore.

Comment by Kiran Appiah [ 01/Nov/13 ]

You know the purpose of sneaking is to avoid falling of edges. So this feature is still bugged

Comment by Brandon Bourgeois [ 01/Nov/13 ]

Affects 1.7.2. No longer an issue at the "half step" of the stairs. You can only fall when sneaking down the steps on the edge.

Comment by Ben W [ 29/Aug/13 ]

Affects 1.6.2.

Comment by Brandon Bourgeois [ 24/Jan/13 ]

I don't think it's a duplicate, but they are both already related. The underlying code may be the same for this bug.

Comment by Anon Ymus [ 20/Jan/13 ]

Duplicate of MC-2334?

Comment by Anon Ymus [ 20/Jan/13 ]

Can you post a screenshot of one?

Comment by Kiran Appiah [ 03/Dec/12 ]

there are certain configurations whereby you can fall off roofs made of stairs/half slabs

Comment by Anon Ymus [ 03/Dec/12 ]

But I can only seem to fall off stairs if there is NO drop.

(S = stair, A = air, B = block)

AA
AA
SA
BB
I CAN fall off here

AA
AA
SA
BA
BA
BA
BB
I CANNOT fall off here

AA
AA
SA
AA
AA
AA
BB
I CANNOT fall off here

Therefore, fall damage is impossible.

Comment by Brandon Bourgeois [ 03/Dec/12 ]

That is exactly what I am talking about. The "half point" of the stair block is the point in which sneaking does not work.

Comment by Anon Ymus [ 02/Dec/12 ]

I was able to sneak down the roof, but not off of it. I don't see how that could cause damage.

Comment by Kiran Appiah [ 02/Dec/12 ]

Have you thought about when you are making roofs for your houses and you are sneaking while descending down the stairs, and then you fall off. Fatal if it were a tall house

Comment by Anon Ymus [ 02/Dec/12 ]

As far as I can tell, when the slab is on top of the block, which is one block above the ground, sneaking works fine. It is only sneaking off a slab that is 0.5 blocks off the ground where the sneaking doesn't work.

Comment by Brandon Bourgeois [ 02/Dec/12 ]

Anon, I don't understand what you mean. You need it for the same reason you need it on any other block, so you can look over the edge without falling. And of course you can fall more than 1 block if there if more than a one block space below the spot where you fall off.

Comment by Anon Ymus [ 02/Dec/12 ]

Why would you need it on slabs or stairs? You can't fall more than 1 block.

Comment by Kiran Appiah [ 01/Dec/12 ]

well that renders the sneaking feature useless on slabs/stairs

Comment by Aden McKinley [ 06/Nov/12 ]

The sneaking will not stop you falling of non-full blocks (like stairs, slabs and repeaters

Comment by Brandon Bourgeois [ 06/Nov/12 ]

Seems like a bug to me. I thought the point of sneaking was so that you couldn't fall off edges.

Comment by Mr Valderhaug [ 06/Nov/12 ]

same for half slabs

Comment by Orion Humphrey [ 06/Nov/12 ]

I don't think this is a bug. It also happens when you are on a ledge and you stand on a repeater and shift to the block next to it.

Comment by Chalmes (Jon) [ 06/Nov/12 ]

It's because in between steps you fall for a split second, which invalidates the sneaking. It seems to happens either between stair blocks, or even in the transition between steps of the same stair block.

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