Moshpits Simulation | Hacker News Reader

Moshpits Simulation

mattbierbaum.github.com

115 pointsBIackSwan41 comments

Too late to complain about lack of circle pit and wall of death. However, I will point out that it kind of seems like it assumes a uniformity of violence, whereas empirically speaking you always have at least one person who is just seriously dangerous either due to intoxication or mental issues combined with large stature/strength. This person both repels others with a stronger force as well as draws in/invites the odd skirmish. Also missing is the fact that in certain scenarios, the non-moshers will aggressively shove the moshers back into the pit, versus here where it seems like they simply tolerate them to whatever extent packing will allow.

My thinking exactly. Cool science project, but doesn't resemble a real life pit at all. The circle pit and people pushing along the perimeter are required.

haha. Maybe I got caught up watching this a little longer than you guys, but at times the pattern does begin emulating a circle pit. Both directions.

It's sort of hard to determine a "push" from the perspective of spheres, but IIRC I saw some of that behavior as well. I mean pushing insofar as red pieces would occasionally move erratically away from the walls.

I do agree about the lone mad rager acting as an unstable epicenter, though. That's key behavior, and something I did not notice in this simulation.

Yes, the most interesting thing about moshpit behavior is how it expands and contracts. There's not a constant level of activity either, things will often calm down during a verse to reignite during the chorus.

Interesting that they broke it down into only two types of particles: moshing and not-moshing. In my experience there should be a third particle for the "border guards" -- the people who help keep the shape of the pit and actively push people back in (as opposed to a non-mosher particle which merely absorbs hits).

Don't forget the natural variability of said border guards who might, should their favorite song enter the scenario, join the moshing group.

Also theres people who will avoid the moshers unless specifically behind 'border guards' - in this simulation everyone essentially acts as border guards; the grey dots dont try to avoid the red just hold their ground.

Really cool app though!

I'm actually far more impressed (or stunned) that there is a paper for "Collective Motion of Moshers at Heavy Metal Concerts". Does this qualify as science?!

Edit: Ah well, i always thought a paper would be like a diploma or similar, turns out it is a 2 and a half page article written by 4(!) people who watched youtube to simulate red dots in a mass of black dots. Anyway, i'm underwhelmed.

Feynman would study what interested him. We got some valuable work because he happened to wonder why X does Z.

So long as the work is rigorous there's nothing wrong with studying collective motion of moshers at heavy metal concerts.

Agreed... my initial reaction to this was "maybe this will explain that Slipknot concert!"

It doesn't have to be world-changing or life-saving to be interesting (though those things certainly don't hurt... usually).

To me it looks like it's ridiculing science papers.. 4 students writing 2 and a half pages about "MASHers", with a bunch of youtube links as source material. Yeah, science! The fact that the story is prominently posted by dailymail filed under "sciencetech" is ridiculous as well.

Call me when you find stadiums build on Jesse Silverbergs great principle of MASHers, that save so many lives.

To me it's a shame that this appears publicly posted on a universities site. I suppose that, for this to happen, a Professor must have agreed and supported this paper.. ugh.

P.S.: I do understand very well that simulation of crowds, especially in buildings, is very important but i feel that this is making fun of serious scientists putting real effort into such work.

Point taken. I should have paid more attention, I did not realize this was being passed off as something like that.

It would certainly be interesting to hear Feynmans opinion of a 2 page "science" paper about drunken heavy metal fans smashing their heads together :P

Feynman always seemed to enjoy doing physics for fun and not just because it was necessary to advance science or anything like that. A classic example is his spinning plates story [1].

[1] http://www.physics.ohio-state.edu/~kilcup/262/feynman.html

Yet, he didn't write a scientific paper about what he considered "just playing around". Same as i wouldn't write a paper about writing "hello world" in visual basic. Yet, i could become a world famous programmer, scientist and then write a paper about whatever started with learning how to program. There is a big difference here.

Feynman worked on the plates problem just for his own, he didn't intent to publish a paper on "how does a sign on a plate look when the plate wobbles" and certainly he didn't expect people to tell him how important his scientific research on plates could be for the world :P

Or, to put it another way: I wouldn't find the paper ridiculous if it would just be a Javascript on github by a guy who finds it interesting how people move in a rock concert.

In fact, it's not even a realistic simulation. I think you may agree when you have ever been at a heavy metal concert.

Don't get me wrong, I partly agree with your stand. My problem is that is hard to dismiss something just on the basis of "it is not science since is not useful", because is almost impossible to draw a dividing line. Many useful discoveries were the product of people just "fooling" around and I believe that this attitude should be encouraged in science. Yeah, you will always have those guys who go and analyze how people slam into each other in rock concerts, but they are just outliers, most people out there are producing research that has some kind of usefulness.

He'd probably be amazed that such research and simulation could be done by just a four man team on a low budget. Maybe wonder how some entry level researchers got access to expensive computing time.

After that he might think about what similarities there are between moshpits and high energy particles in a nuclear fusion kind of environment, and if that could be simulated in the same manner.

Well, he would have stopped the bongos and asked the stripper to get him another drink and then read the "paper", asked a question or two that made the authors realise just how much stuff they'd missed, and a few days later he'd have solved the unseen hidden deep really interesting problem that the authors weren't even aware of.

The first thing he would probably learn is that it's not just heavy metal fans, and that they aren't "smashing their heads together."

Not sure what your problem is, but I've been in my share of mosh pits, and I've never done it with a drop of alcohol in my blood, nor have I ever smashed my head into someone else's. It's mostly shoulders and backs and the occasional elbow.

If you'd rather go meta, there's a metal song about moshing:

http://www.youtube.com/watch?v=sWWdgCqh-1g

"Toxic Waltz" by Exodus. Great song, fantastic album.

I'd rather let the paper simulate this: https://www.youtube.com/watch?v=KuiZTV39Mh0&feature=play... :)

edit: Oh well, 2007 was a much better year: https://www.youtube.com/watch?v=Qs0LvyuiqjM&feature=play...

Agreed fully! Now, if only this simulation did more with the "Wall of Death" and circle pits you see at most thrash metal shows.

My favourite: S.O.D. The Milano Mosh - http://www.youtube.com/watch?v=pNKKAXtaxco

  You think that, you're really hard
  You think that you can mosh
  Got your suspenders, and got your boots
  You'd better wear armor, you fuckin' fool
  WE MOSH, until we die,
  WE MOSH, until you try.
  You think, that you can try,
  But can you do ... the MILANO MOSH !
  REPEAT VERSE

http://www.youtube.com/watch?v=LpClopxgGFY - Fishbone's "Swim" is in the same category.

Shit... that's 20 years old.

Ofcourse this is science. Science is observing something and writing down what you observe.

If you read the research group's page about their mosh pits research you'll find that their intention is to model the behaviour of riots (as in the potentially dangerous situations that sometimes erupt from large gatherings of people).

Not that it needs any relation to real world problems for it to be qualified as science.

I first read this on New Scientist a couple of weeks ago.

Link here: http://www.newscientist.com/article/mg21729055.700-mosh-pit-....

It mentions that the physics studied here could have practical applications in emergency planning. Answering questions like, "How does a chaotic crowd behave in an emergency?".

>Does this qualify as science?

That's a surprisingly common, yet elusive and involved inquiry in the philosophy of science.

Rather, than attempting to reach consensus on what "Science" is, perhaps we should be interested in research that aims to follow the scientific method and related principles, irrespective of the subject matter?

Not that realistic for low numbers of particles. Those guys would get their asses kicked for being jerks running around and crashing into people like that!

They definitely wouldn't be wandering around semi-randomly like they do with a low density of particles.

Depending on the genre, they'd probably end up towards the front pushing a few black circles into the stage.

Depends if the band is trying to get a circle pit going it seems to be semi realistic. But in general yes I think people are generally either trying to get closer or fighting off others who are trying to get closer.

Funny, that's exactly what I do in a mosh pit.

You see, the mosh pit is like formation of planets, the heavier and more hardcore elements will gravitate near to the melted center and the light and meek will quickly shy away from it.

At the least in the moshpits I see in small gigs here in Brazil, the ones at the edge of the pit will generally be walling the melted elements because staying at the edge pushing the weirdos back to the pit is just as fun as being there ;p

The math behind it, from "Collective Motion of Moshers at Heavy Metal Concerts"

http://arxiv.org/pdf/1302.1886v1.pdf

I wonder if they properly controlled for the type of concert. In my experience, moshing will vary by genre with hardcore moshers tending to be more independent (see: windmills and kung-fu kicks). I also recently swapped coasts and noticed that West Coast pits seem to seek out the torodial "circle pit", while East Coast pits a more chaotic.

It is a neat idea for a paper, but it seems like it needs a bit more thought to be useful for real-world applications.

If you increase the box size, it just becomes a bunch of idiots running around on a large field and some people watching them.

This seems like it can be used to simulate a liquid well. If gravity acceleration is added, then the whole thing is blurred and a threshold applied, you can get something like this: http://www.patrickmatte.com/stuff/physicsLiquid/

Missing is - 1. Wall of death. 2. Collapse of the mosh when one person trips over. 3. Crowd surfers and the effects of a boot to the head.

It's neat, I can get a flow going from left to right and it manages to stay stable. Doesn't seem useful till we have torodial moshpit though.

Dude, you need to autoplay the audio on page load.

Yay HORSE the band as a soundtrack!

Reply on news.ycombinator.com