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New formula for glass breaking feats.

ByArrow

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A new formula for glass breaking feats was created by @Perequeliri993. And this formula was approved by @Ugarik and @Flashlight237. And since the formula was approved, it has been used in many different calculations. Here are some of them;
vsbattles.fandom.com

MTV Ghostface breaks a window

vsbattles.fandom.com vsbattles.fandom.com

vsbattles.fandom.com

Sherlock Holmes: Glass Breaker

vsbattles.fandom.com vsbattles.fandom.com

vsbattles.fandom.com

Sherlock BBC Calc: Sherlock breaks a window.

vsbattles.fandom.com vsbattles.fandom.com

Mr.bambu said that this formula is not officially approved and needs approved beyond simple math approval. So I am opening this to officially approve this formula and add it to the calc page

Those who approved the formula;

Those who do not approve the formula:
 
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I was one of the two Calc Groupers to approve the feat back then (the other being @Ugarik ). I'll join in on the list of Calc Groupers who approve the formula.
 
The consistent issue with glass feats is that any values and methods we've used up to this point have returned strictly absurd values, predictably because our hazy guesswork system of pseudo-science ignores a lot of the minutiae in any given physical feat. We have an imperfect system that creates progressively more ridiculous results. In very high tiers, this isn't really noticeable in many instances- but down at the bottom, where 10-C feats return 9-C to 9-B results because the distance between tiers is very very small, it becomes an issue.

Take a look at those example calculations. Literally anyone can break a window. I've done it. Practically anything can. Weapons are only necessary for most instances because the alternative is cutting the hell out of your hand.

Because it's such a human level thing to do, why would directors and producers shy away from doing it? So we will have an endless sea of objectively human level characters producing feats our wiki seems content to describe as Wall level. Superhuman! For shattering glass! It's not hard to imagine, that second feat is missing the mark by only about 3%.

Humans can break glass windows. This seems so fundamentally known that it is actually hard to find much evidence on the subject (perhaps also because of the danger implicit in actually doing it). Destroying a window shouldn't be considered a 9-C feat, whatever our botched system of mathematics dictates.
 
I agree with Bambu on this, although I admit I cannot judge if the above method is even sound to begin with.

I've actually broken a window with my bare hand, cut my hand doing so in fact, when I was still in elementary school. I see this on the same level as falling from normal height. Are system isn't 100% accurate and the more precise/lower we try to get, the more obvious that imprecision becomes.

When dealing with obviously human level feats, like breaking some glass or falling from a reasonable height, just because the "results" give us a certain value doesn't mean we should actually use it. All of the calculations in the OP look extremely human level to me, I very much hesitate in believing these results should be used.

Note: My knowledge on the formula itself is very limited, as I said above I cannot truly say if it's accurate or not. This is just an issue I have with these feats in general.
 
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I'm very cautious about how to handle this.

The evidence Bambu provided was incredibly flawed (the first of those wasn't glass, it was ice; the second one largely involves smaller and likely already flawed/strained objects; the third one involves auto glass which is designed to be broken by tools by humans for safety reasons).

I don't have personal experience with breaking glass with one's body, so I would've assumed that doing so with your body is slightly into 9-C (albeit not as high as these calcs show). But if Rusty can attest to having done so themselves, then I'd be inclined to put it lower. Then again, it's not like glass walls around cubicles are regularly shattered by people bumping into them.

So far, I find the information insufficient to draw a conclusion.
 
The evidence Bambu provided was incredibly flawed (the first of those wasn't glass, it was ice; the second one largely involves smaller and likely already flawed/strained objects; the third one involves auto glass which is designed to be broken by tools by humans for safety reasons).
Click to expand...
Didn't catch that the first one isn't glass (although it bears mentioning that the destruction values for ice used to be higher than those for glass- something to be said about that, maybe), the second one shows people doing it physically (as well as with tools, as mentioned), the third one directly mentions doing it with feet. As for being designed to be broken, they are similarly designed to withstand some force- glass has greatly variable contextual breaking conditions. Still, your say is acknowledged.
 
Mr. Bambu said:
Humans can break glass windows. This seems so fundamentally known that it is actually hard to find much evidence on the subject (perhaps also because of the danger implicit in actually doing it). Destroying a window shouldn't be considered a 9-C feat, whatever our botched system of mathematics dictates.
Click to expand...
As Agna said, the first one is not glass. For the second video: Since people can be 9-C with equipment and various throwing things, it is normal for those using equipment and tools to break the glass.

As for the ones that seem to physically break it: They don't hit the glass directly. They hit the sides of the windows or glass. And the glass is more vulnerable to the blows from the edges.

the third one says that even The third says that even if you punch the glass all day, you may not be able to break it..

In this video, the guys have a hard time breaking the glass. And there are other videos like this. On the other hand, there are videos like this one where boxers break glass.

There's also a video where the horse can't break a window.
 
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The problem here is that it basically tries to use a proper approach and then in the middle turns around and throws our hugely oversimplified stuff in the mix. I think the result essentially is a best of both worlds scenario, where the pressure is taken from one approach but then applied to a way too huge volume for that.
So, not really sure about that approach.

Isn't going to be helpful, but I have been itching to mention it, so I'm just going to do it here:
I have written my Master thesis in mathematics on the subject of (a specific approach to) crack propagation in brittle materials, so I actually know a little about that now... as much as a mathematician that didn't do physics in Uni understands 😁
A proper way to simulate the cracking can be found here (not my paper, to be clear lol). Chapter 1, 2, 3.1 and 4.1 are the interesting parts for us. It describes a way to figure out stress and displacement in a breaking brittle material over time, given certain constants. One can also reverse the approach to find the constants after having seen how a material fractures, although that paper doesn't describe that part.
Now, my knowledge in continuum mechanics is admittedly too limited to say for sure how to figure out work from that. I think it should be as simple as integrating the stress tensor over the edge the force is applied to, in order to get force, and then integrate over displacement (for simple cases), but I ain't 100% sure. One could probably ask in a physics forum or something.
Not that it really matters. The approach is way too much work to be practical (quite possibly more work than is actually needed if you just want to figure out work).
 
Yeah, there can be some ramifications. Our ratings for feats tend to be overexaggerations and such. I mean, windows can be tough, as the AVGN can attest by intentionally trying to break one:



At the same time, part of the equation for glass-breaking is how the glass itself is shaped. A glass sphere, for example, is very resistant to being broken by a hydraulic press:



A window is rectangular in shape, which would mean that hitting the right spot on the window to break it would be much easier to do.
 
ByArrow said:
As Agna said, the first one is not glass. For the second video: Since people can be 9-C with equipment and various throwing things, it is normal for those using equipment and tools to break the glass.

As for the ones that seem to physically break it: They don't hit the glass directly. They hit the sides of the windows or glass. And the glass is more vulnerable to the blows from the edges.

the third one says that even The third says that even if you punch the glass all day, you may not be able to break it..

In this video, the guys have a hard time breaking the glass. And there are other videos like this. On the other hand, there are videos like this one where boxers break glass.

There's also a video where the horse can't break a window.
Click to expand...
Again. Second one shows people doing it without tools, which you don't acknowledge, and the third one mentions doing it without tools (kicking). Breaking glass (in significant volumes) without tools is then objectively possible.
 
No need to bump so many times, I feel xD

I'm on the fence about this, like many others here... I also got a weird feeling when seeing the results for these calcs, I approved some because the math seemed fine at a glance but it was always done with an eye twitch tbh lol (in no small part to personal experience of breaking glass with ease even at a young age, though glass varies and yadda yadda as Flash pointed out so... I remain unsure)
 
Isn't the issue that the entire area of the glass is being considered? In many cases, it's enough for a single part to break for the rest to shatter in a chain reaction due to its fragility. If that's the case, wouldn't it be more accurate to calculate only the area of the part that directly impacts the glass?

For instance, in this specific case, instead of using the total area of the glass, wouldn't it be better to consider only the area of the foot that made the initial impact?
AQpO70A.png
 
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Kulf_Boba said:
Isn't the issue that the entire area of the glass is being considered? In many cases, it's enough for a single part to break for the rest to shatter in a chain reaction due to its fragility. If that's the case, wouldn't it be more accurate to calculate only the area of the part that directly impacts the glass?

For instance, in this specific case, instead of using the total area of the glass, wouldn't it be better to consider only the area of the foot that made the initial impact?
AQpO70A.png
Click to expand...
This is a part of it I have considered in the past. Still, the calculations return results of 9-C for, say, falling through glass (thus making the area of impact approximately equal to your body's frontal surface area, even though in practice one bit of the body would hit it first). I think glass in general is unreliable, but this is certainly a part of the question "why".
 
Kulf_Boba said:
Isn't the issue that the entire area of the glass is being considered? In many cases, it's enough for a single part to break for the rest to shatter in a chain reaction due to its fragility. If that's the case, wouldn't it be more accurate to calculate only the area of the part that directly impacts the glass?

For instance, in this specific case, instead of using the total area of the glass, wouldn't it be better to consider only the area of the foot that made the initial impact?
AQpO70A.png
Click to expand...
Makes sense. He could've also hit the glass at the right spot, which would make the glass easier to break. The same "hitting the right spot" logic would apply to other brittle objects like ceramics and diamonds.
 
Gonna put my two cents here: I have broken commerical glass as a kid, and it was pretty thick (around 2 inches). However, it took me multiple hits and I was enraged at the time. Plus, I didn't use my fists, but my elbow. If a person is able to break glass in one hit, then they are most certainly above human.
 
I don't think we can just multiply by full depth here as glass is very brittle material and performs minimal elastic deformation before breaking. Value for displacement is very small part of depth (something around 0.1%) so energy value becomes way more than should be.

And yes I know that we use same logic for destruction values but using it for a human level feat doesn't make sense to me (as others have already stated).
 
Mr. Bambu said:
The consistent issue with glass feats is that any values and methods we've used up to this point have returned strictly absurd values, predictably because our hazy guesswork system of pseudo-science ignores a lot of the minutiae in any given physical feat. We have an imperfect system that creates progressively more ridiculous results. In very high tiers, this isn't really noticeable in many instances- but down at the bottom, where 10-C feats return 9-C to 9-B results because the distance between tiers is very very small, it becomes an issue.

Take a look at those example calculations. Literally anyone can break a window. I've done it. Practically anything can. Weapons are only necessary for most instances because the alternative is cutting the hell out of your hand.

Because it's such a human level thing to do, why would directors and producers shy away from doing it? So we will have an endless sea of objectively human level characters producing feats our wiki seems content to describe as Wall level. Superhuman! For shattering glass! It's not hard to imagine, that second feat is missing the mark by only about 3%.

Humans can break glass windows. This seems so fundamentally known that it is actually hard to find much evidence on the subject (perhaps also because of the danger implicit in actually doing it). Destroying a window shouldn't be considered a 9-C feat, whatever our botched system of mathematics dictates.
Click to expand...
humans can break glass yea, but in certain contexts windows can be very large, breaking/fragmenting a very large window seems beyond human thresholds.

even looking at a standard home window in your own home, they appear large, and multiple fictional characters have broken a whole window, which can be very large.

though i am not a expert on calcing and im not very well educated on the matter. so i can be very wrong
 
The calculations need to apply the area of contact correctly. It's usually the elbow (~4.15 cm²). That contact is when the energy to break the glass is transferred. Anything after that is pushing shards that offer very little resistance.

So the application goes like this:
1) 21.43/(half of the smaller between the width or the height of the glass panel in cm or radius of main breakage if it just cracked)^0.5 = Pressure in MPa
2) Force = Pressure times area of impact (usually elbow, 4.15 cm²)
3) Multiply the force by the thickness of the glass, usually 3/32 inch (0.00238125 m) to get the Energy through Work.

The step 3 is questionable for the force not really being applied all the way through the glass before it breaks.
 
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