[0.23] Alternis Kerbol - Release thread - [v0.1, Jan. 3] (development halted)

[team.leit]

Completed mission to super-Tylo:

Sorry for the bad quality. Besides the lag, it was actually surprisingly easy, about the same as an Eve sea-level mission except with higher TWR. 48-7S's are awesome.

Most of the video is sped up 4x and the launch is sped up 32x.

Looks like an orange mushroom during the descent,

[NovaSilisko]

Completed mission to super-Tylo and back:

Sorry for the bad quality. Besides the lag, it was actually surprisingly easy, about the same as an Eve sea-level mission except with higher TWR. 48-7S's are awesome.

Most of the video is sped up 4x and the launch is sped up 32x.

Well, color me impressed! Good work. Here are your two gold stars, wear them proudly:

★★

Now do it with Deadly Reentry and a life support mod c:

This is not a very good fix, because the bodies still end up at random places on their orbits (meaning you can't really easily set up a resonance or just move planets around their orbit by tweaking the anomaly).

This is a good fix (stolen from Real Solar System):

// // // Three lines of context
cb2.hillSphere = GetNewHillSphere(cb2);
cb2.orbit.period = GetNewPeriod(cb2);
cb2.timeWarpAltitudeLimits = newWarpLimits; // <<<  Line 864
// // // Insert fix:
// NathanKello Gratias. This comes from anomFix in RSS.
cb2.orbit.meanAnomaly = cb2.orbit.meanAnomalyAtEpoch; // let KSP handle epoch
cb2.orbit.orbitPercent = cb2.orbit.meanAnomalyAtEpoch / 6.2831853071795862;
cb2.orbit.ObTAtEpoch = cb2.orbit.orbitPercent * cb2.orbit.period;

Now the bodies are where they should be, and therefore the spacecraft doesn't spawn in interplanetary space.

You can (and you probably should) keep "cb_sun.OrbitingBodies.Remove(cb_kerbin)".

It seems the orbit class is a complete mess, and as a result doesn't update all its orbital parameters to match what you give it. You might want to file a bug.

I'll try running a simulation of the system I get from this fix using Mathematica's symplectic integrators.

EDIT:

Okay, this messes up Gilly and Ike, as you move them by tweaking the epoch. May I suggest moving them by changing the meanAnomalyAtEpoch instead? This would make things more consistent anyway.

If my calculations are correct, setting M0=2.87273 for Ike and M0=6.15089 for Gilly takes them to where the epoch shift should put them.

Thank you. I'll do that now! You get a gold star too.

★

Edited December 30, 2013 by NovaSilisko

[Mattasmack]

...

This is what I get when the game first loads:

[LOG 17:23:50.123] ALTERNIS KERBOL TRACE: Kerbin
[LOG 17:23:50.124] Mean Anomaly: 3.14000014586568
[LOG 17:23:50.124] True Anomaly: 179.912318783786
[LOG 17:23:50.125] Semi-Major Axis: 68506000
[LOG 17:23:50.126] Eccentricity: 0.02
[LOG 17:23:50.126] Argument of Periapsis: 0
[LOG 17:23:50.127] Inclination: 0.4
[LOG 17:23:50.127] Longitude of Ascending Node: 0
[LOG 17:23:50.128] Epoch: 0
[LOG 17:23:50.129] Mean Anomaly at Epoch: 3.14000010490417
[LOG 17:23:50.129] Eccentric Anomaly: 3.1400313714949

...

So ... the game reports true anomaly in degrees, but the other anomalies in radians?! Good grief. Do you happen to know what units the other angular parameters are in? Just from looking at the orbits in the game's map view it seems that inclination is in degrees, but I can't really tell about the argument of periapsis or longitude of ascending node. I suppose if it reports the LAN as 180 for some bodies (rather than wrapping it into the range 0 .. 2*pi) that's evidence that it's in degrees, but I don't really want to trust that. (Or, is there documentation of this stuff somewhere that I should know about?)

[eggrobin]

So ... the game reports true anomaly in degrees, but the other anomalies in radians?! Good grief. Do you happen to know what units the other angular parameters are in? Just from looking at the orbits in the game's map view it seems that inclination is in degrees, but I can't really tell about the argument of periapsis or longitude of ascending node. I suppose if it reports the LAN as 180 for some bodies (rather than wrapping it into the range 0 .. 2*pi) that's evidence that it's in degrees, but I don't really want to trust that. (Or, is there documentation of this stuff somewhere that I should know about?)

Documentation?

There's this by Anatid, but it's very incomplete (and probably outdated).

The game seems to handle angles in degrees, but the mean anomaly is not an angle, so it keeps it in radians... Sense cannot be made from this. Why can't it just use radians for everything?

Thank you. I'll do that now! You get a gold star too.

★

Thanks!

Edited December 30, 2013 by eggrobin

[NathanKell]

Mean anomaly (at Epoch) are the only params in radians IIRC; everything else is in degrees.

Documentation? Of course not.

[tajampi]

Wooooawww (My first reaction to this mod)

It's... amazing... You always surprise me, Nova

But, i cannot download it actually because of 3 reasons:

1.- My computer is mostly like an old toaster and runs Ksp at 15 fps, or even less when i look at the ground; i imagine the framerate with this installed...

2.- The mod seems to be a little buggy at the moment (As far as comments say)

3.- The system is not adjustable per save file...

Anyway, when it becomes more stable i will download it, no doubt.

It's surprising how many long awaited by the community mods have been released these months: KMP, Krag Planet Factory, Interstellar and, of course, a mod that makes the Kerbol system 10 times more amazing.

Amazing job Nova, keep it up!

Cheers!

[NovaSilisko]

One note to anyone wanting to run a simulation of Alternis - wait til the next version, I've changed some orbits around and hopefully fixed the weirdness with them.

[Mattasmack]

One note to anyone wanting to run a simulation of Alternis - wait til the next version, I've changed some orbits around and hopefully fixed the weirdness with them.

Ah, I was just working on that. I wasn't 100% confident of the results, but it looked like the Jool system blew up pretty well in Alternis too. Including collisions between moons before they get ejected. Your comets and inclined orbits messed up my neat little arrangement of boxes for displaying the orbits, so I'll continue working on that while waiting for the next version. (Not that I'm complaining; this is fun!)

[eggrobin]

One note to anyone wanting to run a simulation of Alternis - wait til the next version, I've changed some orbits around and hopefully fixed the weirdness with them.

That leaves me some time to find the bugs in my own code; for the moment, my simulation seems to be quite keen on shooting every planet and moon on a straight line out of its orbit...

[NovaSilisko]

Heh. Well, I've fixed the laplace resonance around Jool. Now the three objects are never on the same side of the planet at the same time, so I THINK it should be more stable. I'm also going to manually force the orbital periods, just to be 200% sure that the damn things stay in their resonance.

Would adding an arbitrary number to ObTAtEpoch break anything? I was thinking I could make it start with things "mixed up" as oppose to stuff being at its periapsis/apoapsis, or the moons of Jool all being in a straight line for instance. Basically, I just want to add X number of seconds to the initial universal time, at least where the orbits are concerned.

Edit: right yeah no that's not gonna work. Any way I can do what I proposed, preferably without ruining anything?

Edit2: I think I got it, cb2.orbit.StartUT

Edit3: No I don't got it

Edited December 31, 2013 by NovaSilisko

[Sauron]

First, this is fantastic work, Nova! You've nailed some game design aspects that the stock game didn't quite get. especially having a large number of fairly accessible places to visit nearby. It'd be great for new players, but I like it too. (Playing with gravity assists is FUN!). Also, I'm really liking the new designs for the various planets (though a more exciting Pol and Bop would be cool).

Unfortunately I've set my sights on a very, very silly (but fun) goal: sustained atmospheric flight on Tylo. So far it's been...interesting. But I'd like to share that brainbug in case anyone else decides to give it a go

[eggrobin]

Basically, I just want to add X number of seconds to the initial universal time, at least where the orbits are concerned.

This is going to sound silly, but if you just want to shift the planets around, how about doing it by hand (or in the code, or in the cfg this class should be turned into ), namely adding 2pi/Period * ÃŽâ€t to the meanAnomalyAtEpoch of each body. Now that the anomalies work as intended, using them sounds safer than tweaking the numerous inconsistent properties of the orbit class...

Mattasmack: I think I'm going to give up on getting a symplectic integrator to work... How high does the relative error of your Hamiltonian go?

Edited December 31, 2013 by eggrobin

[NovaSilisko]

the cfg this class should be turned into

I just prefer to keep it self-contained in one DLL to the best I can to make it easier to use. Plus, RealSolarSystem already lets you reconfigure stuff with CFGs. Maybe I'm just an idiot for not basing this off of RSS and making it all with CFGs but meh...

[Mattasmack]

This is going to sound silly, but if you just want to shift the planets around, how about doing it by hand (or in the code, or in the cfg this class should be turned into ), namely adding 2pi/Period * ÃŽâ€t to the meanAnomalyAtEpoch of each body. Now that the anomalies work as intended, using them sounds safer than tweaking the numerous inconsistent properties of the orbit class...

Mattasmack: I think I'm going to give up on getting a symplectic integrator to work... How high does the relative error of your Hamiltonian go?

Well ... I just ran a simulation out to 400 Ms, and at the end the relative error in energy was 2x10^-11, in linear momentum was 1.7x10^-11, and in angular momentum was 5.8x10^-11. Those are the values I have the program calculate to judge error. The momentum errors are a bit higher than I got running my simulation of the stock Kerbol system out to 3x10⁹ s. But something horrible happens just after 101 Ms; my program spams messages about collisions between Jool and Minmus and thereafter it's forced to use a much smaller time step. It looks like Minmus falls into Jool, but I haven't rendered a movie from the data so I don't know exactly what happened yet. I'm about to start doing just that and go to bed.

Incidentally, I get a collision between Mun and Kerbin at about 8 Ms, then several between Minmus and Jool between 51 and 58 Ms, and another between Minmus and Laythe at 57 Ms. (So running the simulation as long as I did doesn't really make sense anyway.)

This is all done with the initial states of the bodies set using Keplerian orbital parameters exactly as they're stated (i.e., I don't try to make any sort of correction for bodies moving around their barycenter), and of course I could have an error there. I used the stock mean anomaly at epoch for each body, since that seems to be what the current version of Alternis uses (maybe? unless it's random?), except for Gilly and Ike where I used the Mt values you suggested in an earlier post.

[NovaSilisko]

Put up the cloud pack. Forgot to do so earlier. New version of Alternis itself still forthcoming, but the clouds should still work with the old version.

[nonya0992]

The mod is amazing. I have not played in far enough to have any collisions yet but everything else is working great. My only complaint is the sun shining through Jool. I was hoping for an extended period of darkness much like in the movie "Pitch Black." Other than that, I love it.

[bulletrhli]

Is there a way to just take the textures and colour maps for the planets and add them to the stock game? Say, using texture replacer or a mod of some sort?

[NovaSilisko]

The mod is amazing. I have not played in far enough to have any collisions yet but everything else is working great. My only complaint is the sun shining through Jool. I was hoping for an extended period of darkness much like in the movie "Pitch Black." Other than that, I love it.

I don't know if I can fix that... it seems to work fine when you're closer up to it (like by laythe), and IIRC it does it in the stock game too. Any help anyone can give on this subject is appreciated though

[vidboi]

1.- My computer is mostly like an old toaster and runs Ksp at 15 fps, or even less when i look at the ground; i imagine the framerate with this installed...

Interestingly, I've found that my game runs faster with Alternis installed, and I've heard others say the same thing.

[Markarian421]

Thanks for this mod -- I started playing KSP right around when there were new or changed planets (and Easter eggs) in every new major release, and getting out into the solar system to find out what was there was a lot of the driver for figuring out how to build a rocket to get out there. With the solar system mostly static the game through the last several releases it feels much more rote, just trying to go to the same old places with a few new parts. Now I've got a whole new solar system to explore!

I just started playing with this yesterday (probably shortly before you told everyone to wait for the next version!), the only strangeness I've run into that I haven't seen mentioned previously is that MechJeb sometimes has a lot of trouble landing near the space center. It acts like it thinks the ground is many meters higher than it actually is, like it's trying to land in thin air. Not sure if that tells you anything useful -- has anything (like scale height) changed with Kerbin? For me it just means I need to take manual control of the last stages of landing.

[Mattasmack]

Well ... I just ran a simulation out to 400 Ms, and at the end the relative error in energy was 2x10^-11, in linear momentum was 1.7x10^-11, and in angular momentum was 5.8x10^-11. Those are the values I have the program calculate to judge error. The momentum errors are a bit higher than I got running my simulation of the stock Kerbol system out to 3x10⁹ s. But something horrible happens just after 101 Ms; my program spams messages about collisions between Jool and Minmus and thereafter it's forced to use a much smaller time step. It looks like Minmus falls into Jool, but I haven't rendered a movie from the data so I don't know exactly what happened yet. I'm about to start doing just that and go to bed.

Incidentally, I get a collision between Mun and Kerbin at about 8 Ms, then several between Minmus and Jool between 51 and 58 Ms, and another between Minmus and Laythe at 57 Ms. (So running the simulation as long as I did doesn't really make sense anyway.)

This is all done with the initial states of the bodies set using Keplerian orbital parameters exactly as they're stated (i.e., I don't try to make any sort of correction for bodies moving around their barycenter), and of course I could have an error there. I used the stock mean anomaly at epoch for each body, since that seems to be what the current version of Alternis uses (maybe? unless it's random?), except for Gilly and Ike where I used the Mt values you suggested in an earlier post.

Just for grins, here are a few highlights from that simulation:

Javascript is disabled. View full album

By the end of the simulation (400 Ms) Pol and Bop both look like they're on their way out of the Jool system too, but they haven't quite made their escape yet. In the images, the lefthand plot fails to show most of the moons after they escape, so I'm remaking them.

[Ackerfe]

You don't really need to have a KSO network for RT to work well. Go for a lower orbit (for example, 800km) and have a cluster of satellites that have the same orbital period and a low eccentricity.

Well thank you, just didn't want to send something like 10 satellites or more, but i guess i'll do this, thanks for the help

[eggrobin]

I used the stock mean anomaly at epoch for each body, since that seems to be what the current version of Alternis uses (maybe? unless it's random?), except for Gilly and Ike where I used the Mt values you suggested in an earlier post.

It's complicated. At the moment (v0.0), the in-game positions of the planets are as good as random, and this causes the spawning in space bug. Stock anomalies + the M0s I gave is what you get from v0.0 + the anomaly fix. This is what I am using at the moment.

To clarify:

Body             M0               a                e               É / °              i / °              Ω / °              

--------------   --------------   --------------   --------------   --------------   --------------   --------------  

sun              0                0                0                0                0                0

                                              9
moho             3.1400000        4.2750404 10     0.40000000       15.000000        0.25020000       70.000000

                                              9
eve              3.1400000        8.1855503 10     0.0080000000     0                1.0200000        15.000000

                                              7
mun              1.7000000        4.3152000 10     0.0020000000     0                0.10900000       180.00000

                                              7
kerbin           3.1400000        6.8506000 10     0.020000000      0                0.40000000       0

                                              7
duna             3.1400000        3.4598850 10     0.050000000      0                0.70000000       135.50000

                                              11
ike              2.8727251        1.6798808 10     0.95850000       0                28.450000        0

                                              10
gilly            6.1508858        3.4084735 10     0.97050400       79.080000        225.05000        25.300000

                                              7
minmus           0.90000000       1.4740300 10     0.030000000      38.000000        0.030000000      78.000000

                                              10
jool             0.10000000       1.3605008 10     0.017000000      0                1.9570000        0

                                              10
tylo             3.1400000        2.4708887 10     0.030000000      0                1.2200000        0

                                              6
vall             0.90000000       4.9950400 10     0.011000000      0                2.3370000        0

                                              7
dres             3.1400000        1.7580043 10     0.0020000000     90.000000        0.10900000       280.00000

                                              7
laythe           3.1400000        2.7184000 10     0                0                0                180.00000

                                              8
bop              0.90000000       1.2850000 10     0.090000000      25.000000        0.89400000       10.000000

                                              8
pol              0.90000000       1.7989000 10     0.083000000      15.000000        4.2500000        120.00000

                                              10
eeloo            3.1400000        9.0118820 10     0.080000000      260.00000        1.1500000        50.000000

Well ... I just ran a simulation out to 400 Ms, and at the end the relative error in energy was 2x10^-11, in linear momentum was 1.7x10^-11, and in angular momentum was 5.8x10^-11. Those are the values I have the program calculate to judge error. The momentum errors are a bit higher than I got running my simulation of the stock Kerbol system out to 3x10⁹ s. But something horrible happens just after 101 Ms; my program spams messages about collisions between Jool and Minmus and thereafter it's forced to use a much smaller time step. It looks like Minmus falls into Jool, but I haven't rendered a movie from the data so I don't know exactly what happened yet. I'm about to start doing just that and go to bed.

Incidentally, I get a collision between Mun and Kerbin at about 8 Ms, then several between Minmus and Jool between 51 and 58 Ms, and another between Minmus and Laythe at 57 Ms. (So running the simulation as long as I did doesn't really make sense anyway.)

This is very strange. I don't have any collision detection, but the general behaviour is very different in my simulation over 500 days (|ÃŽâ€E|/E0 < 2E-8, ||ÃŽâ€p||/||p0|| < 5E-13, ||ÃŽâ€L||/||L0|| < 1.5E-10, I finally figured out that the reason I thought my energy was way off was that I counted potential energy twice). The Mun runs away around t=1.5 Ms t=15Ms (EDIT: I can't count ), and the Jool system stays very stable from then on.

Pictures are coming once I can get Mathematica to make an animated gif (hopefully without freezing my computer).

EDIT:

Can you give me the RGB values for your planets, so that we use the same conventions?

EDIT 2: Now that I got the times right, it doesn't seem so inconsistent. I'll run the simulation some more.

Edited December 31, 2013 by eggrobin
Colour request

[metaphor]

Just for grins, here are a few highlights from that simulation:

By the end of the simulation (400 Ms) Pol and Bop both look like they're on their way out of the Jool system too, but they haven't quite made their escape yet. In the images, the lefthand plot fails to show most of the moons after they escape, so I'm remaking them.

Very cool. Anything interesting happening in the Tylo system?

[NovaSilisko]

I'm curious to see how long Bop would last with it (optionally) being a moonlet of Kerbin now. I'd guess not more than a day or two.