Radius confusion

[Ebi]

Space is so ridiculously large, or are we so ridiculously small? It's a shame! The only one who is not impressed is Zaphod Beeblebrox.




Thanks Polyh, imageshack.us works fine!

[polyh]

Imageshack creates thumbnails with links to the full sized pictures automatically, I would recommend using them. Your rather large pictures tend to broaden up the boards layout for people with smaller desktop resolutions. As a rule of thumb you should avoid posting pictures wider than 800 pixels directly.

But it's great to see that planets with a realistic size actually work. Will anyone try and make a realistic sun? I guess and may cause problems because a sun of that size will swallow up the planet, the station and even the witchspace nav beacon and its surrounding area. That may lead to uncomfortable cabin temperatures when you approach a space station.

But basically this is just a plaything because it's a game not a sim. But I think realistic sizes would add to the ant in the stadium effect that the real universe provides.

[Frame]

Imageshack creates thumbnails with links to the full sized pictures automatically, I would recommend using them. Your rather large pictures tend to broaden up the boards layout for people with smaller desktop resolutions. As a rule of thumb you should avoid posting pictures wider than 800 pixels directly.

But it's great to see that planets with a realistic size actually work. Will anyone try and make a realistic sun? I guess and may cause problems because a sun of that size will swallow up the planet, the station and even the witchspace nav beacon and its surrounding area. That may lead to uncomfortable cabin temperatures when you approach a space station.

But basically this is just a plaything because it's a game not a sim. But I think realistic sizes would add to the ant in the stadium effect that the real universe provides.

Sun Radius is read only Therefore we cant modify it, or add an extra sun..

This holds true to the main planet as well, as these follows the random generator generated sizes...

[Commander McLane]

Hi Ebi,

let me make an attempt to answer your original question: Yes, sizes and speeds are screwed up beyond imagination in Oolite. You're not the first to notice, and in fact there have been quite some debates about it on this board. If you use the search-function on top of your screen, you may find some of them.

I remember that I once undertook to do some calculations just how out of scale things are, and posted it in some long forgotten thread. The most ridiculous is the speed of light, which appears to be exactly 1 kilometer per second (as compared to roughly 300000 km/s in our universe), but - as you discovered - even the sizes of stellar/planetary bodies and their relative distances are completely out of scale, e.g. distance from sun to planet 1000 km (as compared to 150,000,000 km sun-earth).

Anyway, the point is, the game is not just screwed up or faulty. What you are noticing is the result of a deliberate decision, and there is a reason behind it.

First of all - as you may know - Oolite is the attempt to recreate Elite with modern means for modern times. So what Aegidian - the creator of the game - did, was to recreate the universe as it was in Elite (roughly, because in fact the different versions of Elite were not in all points identical, for instance as far as ship stats are concerned). So he also recreated the physical appearance of the systems, planet-, sun- and witchpoint-positions and sizes. That's the easy answer: The screwed-up sizes and speeds are simply inherited from Elite.

But there is a second answer as well: I read somewhere (either in an earlier incarnation of this discussion or somewhere in the documentation, I don't remember), that Aegidian at some point actually tried to introduce realistic sizes.

And the whole game became unplayable and boring.

Our brains really, really are lacking the capacity to imagine how huge space actually is. But the truth is: you would never ever find a realistically sized station orbiting a realistically sized planet, you wouldn't even see it before coming ridiculously close. And you would never ever meet any realistically sized ship in a realistically sized corridor, let alone on the planet-to-sun route. Just try to imagine for a moment: It is a journey of one hundred and fifty million kilometers in straight line. About halfway you would pass by a returning sun-skimmer, a ship perhaps 40 or 50 meters big. How close would you have to get to even see more than a fraction of a dot of it on your screen? And just what fraction of a degree, actually fraction of a minute or second would you have to deviate from the absolut exact straight path in order to miss it completely?

So, chances are, you would never ever meet any other trader/pirate/hunter/asteroid in your game. Thus in a realistically sized solar system you would be de-facto completely alone, never meeting anybody, probably not even the station you're heading for.

A game is all about interaction, realistic sizes and distances would effectively kill all interaction in the game. Therefore it's not an option.

The only way out is the way taken already by B&B and later by Aegidian (and - as I read in your post - by other game designers as well): You have to drastically size down the sizes and distances of the planetary bodies, and at the same time drastically size up the ships and speeds.

[DaddyHoggy]

Didn't Frontier use realistic sizes? Which is why you needed a 10,000x normal time button to get anywhere.

I prefer the Elite/Oolite approach from an enjoyability point of view (the physicist in me no longer screams in the back of my head about lack of "true" Newtonian physics* and real sizes - he's too busy enjoying the experience)

*I think a long time ago Ahruman explained that the Ooniverse does use Newtonian physics but in this sense I mean simply that, cutting the thrust of your rear thrusting engines cuts the speed of several hundred tons of metal from 0.35LM to 0 in a few seconds - the actual energy required to do this is astronomical (fnarr fnarr) and would leave you as a thin smear intermixed with some vaporised/wrenched apart metallic fragments (unless you take the Star Trek "Inertial Dampers" approach)

[ClymAngus]

I still think a station round a moon round a gas giant would be cool. -.-

[Eric Walch]

I think a long time ago Ahruman explained that the Ooniverse does use Newtonian physics

Only partially. e.g with colissions. Newton is the most famous about his observation of an apple that fell down. Why does it fall down, and not upward? --> Gravity!!

Where do we see gravity in Oolite?? Nowhere!

I think it was also Newton that concluded that not only the apple falls down to the earth, but also the earth is falling up to the apple. At school we even had to calculate how far the earth falls in direction of the apple: --> very little, much less than an atomic diameter. But it does fall! "weight x distance" is the same for both.

[DaddyHoggy]

Every action has an equal and opposite reaction...

We did the same calc!

[Disembodied]

I think it was also Newton that concluded that not only the apple falls down to the earth, but also the earth is falling up to the apple. At school we even had to calculate how far the earth falls in direction of the apple: --> very little, much less than an atomic diameter. But it does fall! "weight x distance" is the same for both.

Unless there's someone standing on the other side of the planet from you, simultaneously dropping another apple of the same proportions...

Physics joke: a rich Sheikh liked to bet money on horse races. Sometimes he won, sometimes he lost, which didn't matter at all to him financially, but he was always on the lookout for tips or hints or inside information to give him an edge over the other gamblers. He tried this scheme and that, but always it seemed to be just a matter of chance. Eventually, despairing of ever finding a reliable method himself, he turned to science for answers.

First he called in biologists and geneticists, to see if their knowledge could give him the surety he was looking for. But all they said was, "We can give probabilities, and offer indications -- but we cannot give you certainty."

So he turned to the chemists, but they told him the same thing: "We can show you graphs and give you standard deviations, but certainty is beyond us."

Finally he turned to physics and straight away he found a physicist who said "Certainty? Absolutely! I can do it. Just give me a budget big enough and I'll crack this for you."

So the Sheikh founded an institute and gave it an unlimited budget, and only five years later the physicist rushed in to see him, crying out, "Eureka! I have it! The perfect formula for picking the winner in a horse race!" Excitedly, he set up a blackboard and began to explain his discovery to the Sheikh:

"Assume a horse is a sphere, moving through a vacuum..."

[DaddyHoggy]

@D as a physicist (by first degree, no longer by occupation) I've heard many a variation of this one - still makes me laugh though.

A shiny new physics graduate goes for a job interview at a top physics laboratory and discovers in the waiting area that he's up against some astonishingly good competition for the job.

Nervously he goes in, the last man. The three board members eye him up, a copy of his CV in front of them. The chairman speaks up: "We can see from your CV that you do have some potential."

Quick as a flash the graduate leaps off his chair and stands on the seat.

The chairman is incredulous: "What are you doing?!" he demands.

"And now I have even more potential!" replies the graduate.

da-da-tsk!

[Ebi]

Muhahaha! DaddyHoggy, unfortunately your joke cannot compete with the one of Disembodied!

As I said above, Commander McLane, real dimensions are ridiculous. However, it's funny to use them in books and games.

Do you know the stories of Ion Tichy. He once wanted to visit the most famous philosopher of the galaxy. The journey would take 30 years and to be prepared he filled his space craft with philosophical books which he wanted read. But on his way he received an emergency call and he had to brake all autumn long:)

I've started to play FFE. Damn, this game is so cool. Elite 2 & 3 are the only space games I know which simulate gravity. I start at planet Hope and want to go to one of the outer planets. The ships accelerates to 20000Km/s and with still 16 AUs to go the Docking computer begins to brake. The flight lasts 5 days:) It's amazing to see the ship approaching the planet and to land on the surface.

You are right, Oolite is a successor of Elite 1 and it's probably wrong to make it a Elite 2 & 3 descendant. I've learned I just have to ignore physics, it's a game and it's not a simulation.

[JohnnyBoy]

Two mathematics teachers are walking to a coffee shop, arguing. The male teacher says "Hardly anybody understands calculus. Maybe a fraction of a fraction of one percent of the population". The female teacher disagrees; "Look, I think that you're really underestimating this. There must be tens of thousands of people out there who have studied calculus. I think that there are a lot more than you imagine...". And so the argument goes on.

Finally, they arrive at the coffee shop. "You sit down over there, and I'll order the coffees" says the female teacher. While the male mathematician finds a seat, his female companion orders their coffees, pays for them and discretely whispers to the guy behind the counter "Listen, when you bring the coffees over to my colleague and I, I'm going to ask you a question. And in response I want you to say 'x cubed over 3'. Could you do that for me?". So the young man behind the counter says "'x cubed over 3'? Yeah, I can say that."

So the female teacher joins her male colleague and the argument continues. Eventually, the young shop worker walks over to them carrying the drinks that he's prepared. The female maths teacher says to her colleague "Look, let's try my theory out. Young man, what's the integral of x squared?". As the young man puts down her coffee, he says "x cubed over 3". And then he puts down the second coffee and says "...plus c".

[If you find this joke as funny as I do, I'm afraid that there isn't much hope for you....]

[DaddyHoggy]

@JB no hope for me then!

[Dr Beeb]

I remember that I once undertook to do some calculations just how out of scale things are, and posted it in some long forgotten thread. The most ridiculous is the speed of light, which appears to be exactly 1 kilometer per second (as compared to roughly 300000 km/s in our universe), but - as you discovered - even the sizes of stellar/planetary bodies and their relative distances are completely out of scale, e.g. distance from sun to planet 1000 km (as compared to 150,000,000 km sun-earth).

Anyway, the point is, the game is not just screwed up or faulty. What you are noticing is the result of a deliberate decision, and there is a reason behind it.

First of all - as you may know - Oolite is the attempt to recreate Elite with modern means for modern times. So what Aegidian - the creator of the game - did, was to recreate the universe as it was in Elite (roughly, because in fact the different versions of Elite were not in all points identical, for instance as far as ship stats are concerned). So he also recreated the physical appearance of the systems, planet-, sun- and witchpoint-positions and sizes. That's the easy answer: The screwed-up sizes and speeds are simply inherited from Elite.

Hello Commander McLane (and others),

I was struck by your comment about the speed of light being 1 km/s. I haven't looked in the code but did a speed trial myself of sending a Cobra Mk III on a flyby past a space station. On my mac it took Oolite 75s for the Cobra MkII to cover a distance of 25 km, irrespective of whether a planet or space station was being rendered in the view. So this translates to 25/75 = 0.33 km/s ~ 0.33 LM for the top speed of the Cobra Mk III, in agreement with your comment and the literature.

I then went back to older 8-bit versions of Elite emulatable on my mac and did the same test. The time to cover 25 km does depend on what is visible in these versions: rendering the space station slows things down, rendering the planet slows things down even further. I had access to classic Elite BBC disk version for BBC Model B, Tube-enhanced Elite for the BBC Model B, (some videos posted here for those interested http://wiki.alioth.net/index.php/BBC_Micro )
and the (unreleased NTSC version of) the final 8-bit version of Elite for Famicon/NES by Bell and Braben.

In the table below, the first column is the time to reach the space station and fly past it (as indicated by the symbol change on the compass), starting with the station at the edge of the scanner, and the planet behind the spaceship and not in view . Presumably this also corresponds to a distance of 25 km, as in Oolite, but I am not sure. The next column indicates how the apparent speed goes up dramatically once the only thing left to render in the front view is the dust field [D], with the planet still behind the spaceship. The last two columns are for the return trip, now with the planet visible beyond the space station . The last column is after the space station flyby with only the planet left visible in the front view [P].

_________|__S__D_|__B__P__
BBC B disk | 25s 13s | 61s 49s
BBC B tube| 19s 11s | 43s 40s
NES______| 33s 14s | 51s 40s

Taking column S, rendering of space station similar to rendering of some pirate ships when in a dogfight, then the top speed of the Cobra Mk III in the BBC B disk version is 25 km/25 s = 1km/s, the Tube version is slightly faster, NES similar. The elapsed time to traverse the 25 km is NOT the 75s of Oolite, instead these versions have the Cobra Mk III, and other ships, flying around about x3 faster - or else the range on the scanner in these versions is only 8 km, not 25 km ? I doubt the scanner is x3 shorter range because I have found I need slightly different dog-fight tactics in Oolite vs Elite. In particular in Elite if you encountered a group of pirates your best choice was to go at full speed towards them. You were likely to reach them, and disperse them, before your front shield was reduced to zero. In Oolite this tactic is less likely to work, the (regular) front shield tends to be destroyed before covering half the distance to the pirates - instead you are better off sitting stationary and enjoy taking long-range pot shots at the pirates with a military laser before their shorter-range beam lasers come into range.

I was wondering if others have comments as to when the ships were 'slowed down', Elite - TNK? the Archimedes version? Or something done in Oolite to aid the dogfights?

[Frame]

I think it is a fault by design....

for example...in the code we move in a fixed coordinate system position 0,0,7000000 absolute coordinate scheme, is where the precision faults begins to show. flashers only have single precision. and starts to shake... jump in shady cobra.. write player.setPosition(0,0,7000000), in debug console, and you will see what i mean.. the flashers will jitter as you move.. because 0,0,7000000 is afaik, and am pretty sure of, is also the coordinate used internally in the OpenGL code.. with larger numbers & less inaccurate precision comes more inaccurate calculations.

If we where flying faster, we would quicker reach those boundaries.

The solution would be..

To redo the drawing code so that to world moves around the player, rather than now, where to player moves through the world, at least that is how i understand it, from replies from ahruman in the solar system oxp thread...

and that ain't likely to happen...

i´m a bit surprised though, because being very much an OpenGL beginner for 1½ year now, one of the first things i read was..you move the world around the viewpoint.. not the other way around, like what is happening in Oolite