Uploaded June 2025 | Updated September 2026, 1 week ago
Usually, completely clipping through a block is kinda difficult because if the server ever sees that you're more than 1e-5m inside of a block you weren't inside of before, it'll get mad and snap you back to your previous position. As a result, you usually either need a lot of speed to get through it instantly, or for something else to clip you into the block initially. But today I realized you can actually use your server velocity to expand your server and client hitbox up into a ceiling, while convincing the server that it had been there all along so it never gets mad. Sadly this only works upwards since there's no good way to resize your hitbox in any other direction(?), but it's still pretty neat.
The basic idea is that every server tick, your server hitbox will first move by your server velocity. Then, it expands your server hitbox to the tallest possible size it can without clipping any blocks(via un-crawling/un-crouching). This size change itself can't clip you through a block, buuuutttt, right after it does this it immediately resets its position/hitbox back to where it started at the beginning of the tick, without checking if it still fits there. And additionally, whenever your server hitbox changes it forces your client hitbox to change to match it. Soooooo by crawling under a ceiling, and then getting enough server velocity to move your server hitbox out from the crawlspace, it'll think it's fine to fully stand up. This clips you into the ceiling on the server, and then tells the client to follow suit. And since the server now thinks it was always clipping the ceiling, it'll let you just jump up through completely.
To actually do this, I first get crawling right beneath the ceiling, which I did using the 1 block crawl thing from my previous video (youtu.be/s0f-w-EdH5s ). Basically, if you move less than 0.03m into a block position, your server position won't update and you'll still be able to place a block there, even if you're inside of it on the client. By placing a block on my head by 1e-7-1e-5m I'll be forced to start crawling, and by placing one in my feet by at least 1e-7m, or 2e-7m for non-full blocks(secret non-float precise clip?), it'll stop my hitbox from changing while I jump up to right under the ceiling.
Once I'm up on the upper ledge, I move off slightly and then back on to update my server position to be floating in the air. This lets me start accumulating downwards server velocity without actually falling(similar to youtu.be/-EPkAJY9uv8 ). Once I get more than -0.5m/t, the server will fall enough in 1 tick to think there's room to stop crawling and start crouching instead. Of course that's not the case once it resets its position, and so it ends up clipping up into the ceiling instead. And since it changed its hitbox size, it also forces the client to un-crawl and start crouching, extending my client hitbox up into the ceiling as well. And that's pretty much it!
It's only temporary though, and after 1 tick the client will go back to crawling(you don't see it in the video because I'm recording from a server). So you have to jump up into the ceiling on that exact tick before it corrects itself*. This isn't immediately possible though, because the server clipping also gives suffocation damage, which transfers the downwards velocity to the client, killing my jump. So instead, I just wait longer until the server is falling fast enough to go from crouching to standing, which gives me another tick to jump. Except this time there's no damage tick so the jump works fine.
Once in the ceiling I still need another block to land on though, since 1 jump isn't enough to clear the two blocks up to the top of the ceiling. Luckily, once I jump my server position updates, and so there's no longer room for it to stand/crouch, and so it starts crawling again. This of course forces me to crawl on the client, placing my eye level inside the ceiling so I can place a block right under my feet by looking straight up. Then I can FINALLY jump again off of this block, reaching the top.
*This video is kinda pretty old.. I now realize you could just place another block inside yourself while building up velocity(on top of the cobblestone I'm sitting on in the video). This way when the server expands your client hitbox it won't be able to change back since there's a block in your feet. Plus, you can just jump straight up onto that block for free. My first solution was wayyy cooler tho so I'm not re-recording it smh. Plus I realllyyy feel like there should be a easy way to do this with just crouching and less nonsense, and I care about that way more. It's pretty easy to get /into/ the ceiling with just crouching, but I can't think of any way to do it while getting a full block of height into the ceiling. BASICALLY it all sucks cuz my Very Intended Feature doesn't work Exactly The Way I Want..... idkkk have a lovely day... and if you have all my answers whisper them to me in my sleep please..!
Usually, completely clipping through a block is kinda difficult because if the server ever sees that you're more than 1e-5m inside of a block you weren't inside of before, it'll get mad and snap you back to your previous position. As a result, you usually either need a lot of speed to get through it instantly, or for something else to clip you into the block initially. But today I realized you can actually use your server velocity to expand your server and client hitbox up into a ceiling, while convincing the server that it had been there all along so it never gets mad. Sadly this only works upwards since there's no good way to resize your hitbox in any other direction(?), but it's still pretty neat.
The basic idea is that every server tick, your server hitbox will first move by your server velocity. Then, it expands your server hitbox to the tallest possible size it can without clipping any blocks(via un-crawling/un-crouching). This size change itself can't clip you through a block, buuuutttt, right after it does this it immediately resets its position/hitbox back to where it started at the beginning of the tick, without checking if it still fits there. And additionally, whenever your server hitbox changes it forces your client hitbox to change to match it. Soooooo by crawling under a ceiling, and then getting enough server velocity to move your server hitbox out from the crawlspace, it'll think it's fine to fully stand up. This clips you into the ceiling on the server, and then tells the client to follow suit. And since the server now thinks it was always clipping the ceiling, it'll let you just jump up through completely.
To actually do this, I first get crawling right beneath the ceiling, which I did using the 1 block crawl thing from my previous video (youtu.be/s0f-w-EdH5s ). Basically, if you move less than 0.03m into a block position, your server position won't update and you'll still be able to place a block there, even if you're inside of it on the client. By placing a block on my head by 1e-7-1e-5m I'll be forced to start crawling, and by placing one in my feet by at least 1e-7m, or 2e-7m for non-full blocks(secret non-float precise clip?), it'll stop my hitbox from changing while I jump up to right under the ceiling.
Once I'm up on the upper ledge, I move off slightly and then back on to update my server position to be floating in the air. This lets me start accumulating downwards server velocity without actually falling(similar to youtu.be/-EPkAJY9uv8 ). Once I get more than -0.5m/t, the server will fall enough in 1 tick to think there's room to stop crawling and start crouching instead. Of course that's not the case once it resets its position, and so it ends up clipping up into the ceiling instead. And since it changed its hitbox size, it also forces the client to un-crawl and start crouching, extending my client hitbox up into the ceiling as well. And that's pretty much it!
It's only temporary though, and after 1 tick the client will go back to crawling(you don't see it in the video because I'm recording from a server). So you have to jump up into the ceiling on that exact tick before it corrects itself*. This isn't immediately possible though, because the server clipping also gives suffocation damage, which transfers the downwards velocity to the client, killing my jump. So instead, I just wait longer until the server is falling fast enough to go from crouching to standing, which gives me another tick to jump. Except this time there's no damage tick so the jump works fine.
Once in the ceiling I still need another block to land on though, since 1 jump isn't enough to clear the two blocks up to the top of the ceiling. Luckily, once I jump my server position updates, and so there's no longer room for it to stand/crouch, and so it starts crawling again. This of course forces me to crawl on the client, placing my eye level inside the ceiling so I can place a block right under my feet by looking straight up. Then I can FINALLY jump again off of this block, reaching the top.
*This video is kinda pretty old.. I now realize you could just place another block inside yourself while building up velocity(on top of the cobblestone I'm sitting on in the video). This way when the server expands your client hitbox it won't be able to change back since there's a block in your feet. Plus, you can just jump straight up onto that block for free. My first solution was wayyy cooler tho so I'm not re-recording it smh. Plus I realllyyy feel like there should be a easy way to do this with just crouching and less nonsense, and I care about that way more. It's pretty easy to get /into/ the ceiling with just crouching, but I can't think of any way to do it while getting a full block of height into the ceiling. BASICALLY it all sucks cuz my Very Intended Feature doesn't work Exactly The Way I Want..... idkkk have a lovely day... and if you have all my answers whisper them to me in my sleep please..!
