
PhysicsJS Examples: Newton's Revenge - 6ren
http://wellcaffeinated.net/PhysicsJS/examples/#demo-2
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chengsun
Some of the examples (the cloth and the tree) seem to be based off Sub
Protocol's verlet-js demonstration [1], which were on Hacker News a while back
(HN discussion [2]). There was a similar issue with angular momentum not being
conserved on those examples too.

[1] [http://subprotocol.com/verlet-js/](http://subprotocol.com/verlet-js/)

[2]
[https://news.ycombinator.com/item?id=5580596](https://news.ycombinator.com/item?id=5580596)

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jbri
Something seems off about the simulation - once you get a big clump, it starts
spinning faster and faster until it tears itself apart again.

Ignoring that, it's pretty neat - and runs decently fast as well.

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beloch
I noticed that angular momentum seems to be an unconserved quantity as well. I
would not want to be an astronaut in the universe simulated here!

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raverbashing
Yeah, this is almost a planetary cloud coming together.

But I suppose the collisions are (too) elastic, also there's the issue with
the spinning.

But still you can see several concepts in action, and sometimes you get a big
planet with a moon orbiting it.

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jheriko
small niggle. what is a verlet constraint? (rhetorical)

whilst its obvious that you have just discovered verlet integration and the
relaxation method of applying constraints - because everyone goes off and
writes a physics engine at this point - i only think i know what you mean
because i have assumed this.

are these length constraints, angle constraints etc?

still... no matter how common and unexciting this is for me, its always cool
to play with physics simulations for five minutes. thanks for sharing. :)

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joshvm
The tearable cloth demo is impressive!

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toblender
My favorite one was "Supermarket catastrophe".

Been wondering about where I can get a physics engine to simulate wind. I want
to create a wind turbine simulator.

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bsenftner
I had to run in Chrome, as FireFox reported 10 FSP while actually displaying
less than 1 fps. Nice.

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nickthemagicman
This is really cool.

I'd like a 3d version to combine with three.js.

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est
drag "Fruitcake on wheels" like crazy -> get messed up

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japhyr
It took me a while to realize I could play with the objects. It got even more
interesting once I realized I could do that.

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pit
You can really torture those poor trees...

