Spaced out

[chrisvenus]

I'm feeling very strange today for many reasons, not least of all the serious lack of sleep that I got last night. My odd mood has me wanting to go out and do something but of course I am in work so I can't. So instead I am posting to LJ. Its not quite the same thing but breaks up the day a little bit at least.

So what's everybody else up to? talk to me, tell me things, post interesting comments and say interesting stuff. Or uninteresting stuff. I just think people should post things.

For my part I discovered that a leg holstser that I have for roleplaying purposes can be attached to the frame of my bed relatively easily. It was one of those random moments as I saw it lying in the corner and deccided to just see if I could. I should probably take it off again before people worry...

So there's my random comment. Now to go play with stylesheets for work...

Comments

It's supposed to be interesting ... I do not agree.

[lilibel.livejournal.com]

Drawbacks
- May promote inflexibility
- Unrealistic standards may hamper emplyee motivation
- Setting performance standard is time consuming
- Factors beyond employee's control may affect outcomes
- Fact not rewarded may be overlooked

You wanted a comment.
Enjoy the current slide of my HR class.
:p

[bateleur.livejournal.com]

So what's everybody else up to?

You really want to know? Well, OK. I've been wondering why nothing bounces.

If you look at a 2D physics system - of which there are numerous examples on the web now - it looks quite impressive until you realise that nothing's bouncing at all. Every time two things collide they instantly lose all their (relative) KE.

This would just be an implementation detail, but various different implementations all seem to do it. So now I've spent my morning pondering the reason. (What a rock and roll life I lead, eh?)

[innokenti.livejournal.com]

ahahaahahaa thesis ahahahaaha


Should be done by tonight.

[wimble.livejournal.com]

The obvious problem with doing it properly is defining the coefficient of restitution between the various object types.

Sidenote: I can remember asking in my A level maths class what determined the value, because, for example, a marble dropped onto a trampoline doesn't bounce (mostly), but dropped onto a tiled floor, it does. Conversely, a person dropped onto those two surfaces does bounce in the first case, but tends to splat in the second. My teacher (in essence) asked me to go away and stop worrying about it ;-)

On the other hand, setting a global coefficient of (eg) 0.25 wouldn't be too bad.

[ar-gemlad.livejournal.com]

I am procrastinating at work. As per usual.

[chrisvenus]

yay! :)

[chrisvenus]

Well, glad to help in my own small way. :)

Re: It's supposed to be interesting ... I do not agree.

[chrisvenus]

oooh... I'm now curious as to what those are drawbacks to...

[chrisvenus]

That is very weird. Those dropping boxes just look wrong because of the lack of bounce. Even a little bit would be good. Is it a calculations thing that the complexity involve dents the efficiency so much that in most cases since you don't want it you leave it out? I've never really looked at how much calculations would be needed in those collisions and things and how much more would be needed to work out the angles of impact and such like. Though its hard to tell from those demos, do they do it between two objects or if you were to throw two at each other would they just stop dead in the middle, joined together and fall down?

[chaosdeathfish.livejournal.com]

I do not understand the world any more.

I want to hide in a corner and recover from Albion. They won't let me. Bastards.

Got plans for a Broken World character yet?

Oh, and doesn't the phrase This user has turned on the option that logs your IP address when posting sound so clunky? Surely just Your IP address will logged when posting would be much neater and convey just as much meaning? It bugs me.

I need a top hat.

So, Exalted again week after next?

[bateleur.livejournal.com]

On the other hand, setting a global coefficient of (eg) 0.25 wouldn't be too bad.

Indeed. I can see the argument for a flat value, but why zero? (My tentative answer so far is that is has to do with complications arising from the nature of impacts in quantized time.)

Also unless your software needs to support a very large number of different materials there's nothing wrong with having a lookup table for coefficients of restitution. Takes a pair of materials, returns a hardcoded result.

(Incidentally I think trampoline is a bogus example - that would need to be modelled as a complex structure, not a rigid body.)

[bateleur.livejournal.com]

They wouldn't join together as such, so unless they collided absolutely dead flat they'd likely spin away from each other. But deflection due to angled impact is not the same as bounce.

My current theory is that quantized time causes the problem. Why? Because forces are replaced with impulses, but applying gravity as an impulse is problematic in any frame in which a collision occurs. This is because you end up processing each impact at slightly the wrong velocity (since it occurs mid-frame in general but the gravity-adjusted velocity is as at end-of-frame). This sounds like a small effect, but it means objects won't come properly to rest. Instead they'll bobble around as though there's an earthquake going on.

[chrisvenus]

Not had a chacne to think of a final Broken World Character yet. I'm mulling over in my mind playing... something. I dunno. I'm thinking I might leave political stuff to the two term game and do some kind of adventurer/action type for game 1. I've not had a chance to look through everything on the site yet though (and god knows when I will have a chance). I am roughly aware of character gen from looking at the beta (and a quick glance through the revised version) but I need to find hooks in the setting to attach a character too. I do have plans for interleaving with lots of people in backplot (just in terms of having come across other fragments before, etc. so do talk to me later about how we may have met in the past. :)

And I guess the IP logging thing is to make it clear that it is a user option and that the user has access to it rather than that the LJ team log it and only they have access. After all, I suspect even with the option off LJ probably do still log the IP address...

[chrisvenus]

that makes sense. I'm sure I don't need to tell you about modelling but I remember some stuff like that with modelling differential equations without simple solutions and some of the weird effects that you get in programs. Its all about chaos. :)

My thoughts on deflections were that in a way they *should* be a similar principle to bouncing on a floor. However, I can see that approximations could be modelled differently for each of them.

[hrhianne.livejournal.com]

Staring at gmail and going "Why are there no Albion IC emails?" and being bored.

[evath.livejournal.com]

I'm cleaning a mouldy room.

Sucks to be me.

[innokenti.livejournal.com]

Please note lack of a two-term game. They're doing 3 1-term games.


Re: Exalted. I am here next week, but not the two weeks after that. And then back again.

TO THE FUTURE.

[chrisvenus]

Ah, that does make some difference. This is what happens when I don't turn up to society meetings and have the memory of a goldfish. :) You must forgive me for I am old and set in my ways and don't understand these new fangled things. :)

I shall send an e-mail out at some point. Not really thought too much about it yet.

[chrisvenus]

Aww... :) I think this is the point when you need to try to remember what you did in your free time, something you've not had to worry about for the last year... :)

[chrisvenus]

That sounds like you could be having more fun. At least you are taking LJ breaks in between though. Is this at home or work or what?

[bateleur.livejournal.com]

Well the component parallel to the direction of impact is exactly like bouncing on the floor. It's just that in practice if two objects randomly collide in the air they often retain most of their momentum and just change direction a bit, which can make it hard to judge by eye to what extent there was energy lost in the collision.

[bateleur.livejournal.com]

They're doing 3 1-term games.

Hurrah! Actual innovation!

[chrisvenus]

This has been done before with Colony some number of years back. I forget exactly when but I think six or somewhere in that ballpark (I'm sure the web would tell you somewhere but I'm not bothered right now). I can't remember what followed or if there was any good reason not to try it again. It just happens to have not happened that way.

[quisalan.livejournal.com]

I'm in work in Abingdon trying to get patient data off a busted SMC :(.

This is kind of cool, though, considering I woke up this morning in Basel!

[chrisvenus]

:) You jetsetter, you. :)

[quisalan.livejournal.com]

*snickers*

I was on the 7am (CET) flight.

This means I got a taxi at 5.45am (CET). Which is like, 4.45am UK time.

I'm going to be so dead tonight! :)

[jiggery-pokery.livejournal.com]

My wife and I have just watched the last two episodes of series two of the West Wing. I'm working the day shift tomorrow and so need to be up at 5am, so I'm not a million miles away from getting a very early night.

[anotherusedpage.livejournal.com]

What I did today: procrastinated from life with maelstromfaff. Procrastinated from Maelstrom with albionfic. Sang Old Macdonald and then Verdi's Falstaff. Went home.

[evath.livejournal.com]

It was the lab cold room, so 4 C and it was nearly black with mould and stuff people have left in there from years ago. Basically the a fridge the size of my bathroom, and the mould levels of a student fridge after it's been forgotten over the holidays.

Done now though.