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[WIP][1.8.1, 1.9.1, 1.10.1] Principia—version Гельфанд, released 2020-11-15—n-Body and Extended Body Gravitation, axial tilt


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On 5/10/2020 at 1:02 AM, pleroy said:

The FAQs explain how to report bugs.  Note that on Linux you'll need version 8 of libc++ and libc++abi.  Since Xenial is fairly old, these libraries may not be installed on your system.

Thanks. I recently noticed that Steam crashes as well, so it is definitely not a mod problem. I will sort out my Nvidia software until I get Steam to work and come back with an update.

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On 5/10/2020 at 1:02 AM, pleroy said:

The FAQs explain how to report bugs.  Note that on Linux you'll need version 8 of libc++ and libc++abi.  Since Xenial is fairly old, these libraries may not be installed on your system.

I installed libc++1-8 and libc++abi1-8 and I can now start a new game. I did a test flight and everything looks good. Thank you very much for your help.

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Hi!

Do you have problems with contracts, where you need to place vessel on specific orbit? I'm trying to place vessel on orbit around Mun, but it doesn't work. I've also checked direction;) Putting vessels on specific orbit around Kerbin works fine. The problem with Mun that orbit slowly changes because of Kerbin influence.

Zmrpzpq6G5Y.jpg

 

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Posted (edited)
On 5/19/2020 at 5:32 AM, VladTs said:

Do you have problems with contracts, where you need to place vessel on specific orbit? I'm trying to place vessel on orbit around Mun, but it doesn't work. I've also checked direction;) Putting vessels on specific orbit around Kerbin works fine. The problem with Mun that orbit slowly changes because of Kerbin influence.

I believe that this is a well-know annoyance of the stock contracts with Principia.  They are based on 2-body mechanics (a.k.a. conics) and don't work well in the presence of more complex trajectories.

I also believe that KerbalismContracts plans to support more realistic contracts that would work well with Principia.

Edited by pleroy
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For the new moon (lunation number 252), the new release (Fuchs) is out.

  • The issues with rotation (uncontrolled spin-up, jerky motion, oscillations, etc.) introduced in Frobenius and Fubini have for the most part been solved. We are aware of one remaining case of aberrant spin-up, reported by @scimas, but this seems to be a very rare issue at this point.
  • Prior to ignition, the manœuvre node marker on the navball for guided burns now points to the orientation at ignition, instead of following the current Frenet frame. This is more useful for manual burns (the spacecraft can be oriented correctly prior to ignition, instead of having to be guided even before the manœuvre starts). Perhaps more importantly, in conjunction with change MuMech/MechJeb2#1264 (available in MechJeb dev builds ≥ 958), this means that MechJeb can execute all Principia manœuvres.
  • New APIs have been added for use by @Sir Mortimer’s KerbalismContracts.

See the change log for more details.

We support two sets of versions of KSP: downloads are available for 1.9.1 & 1.8.1, and for 1.5.1, 1.6.1, 1.7.x. Make sure you download the right one (if you don't, the game will crash on load).

For the convenience of our Chinese users, the binaries can be downloaded either from Google Drive or from 腾讯微云.

This is the last release to support KSP 1.5.1, 1.6.1, and 1.7.x, as Realism Overhaul and Real Solar System now support 1.8.1.

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22 hours ago, pleroy said:

I believe that this is a well-know annoyance of the stock contracts with Principia.  They are based on 2-body mechanics (a.k.a. conics) and don't work well in the presence of more complex trajectories.

My best guess is that the "maintain stability for 10 seconds" part of the contract fails because Principia keeps changing the orbit information all the time. My advice: cheat it to completion, and never take such a contract again, ever. (They're boring anyway)

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13 hours ago, Sir Mortimer said:

My best guess is that the "maintain stability for 10 seconds" part of the contract fails because Principia keeps changing the orbit information all the time. My advice: cheat it to completion, and never take such a contract again, ever. (They're boring anyway)

In my experience, it's actually the parameters themselves not matching is the problem. When the state of the vessel is such that the "one SOI at a time" is not a good approximation of N-body physics, the magnitudes or anomalies of various nodes differ significantly from the conic approximations. If you turn on the "show patched conics" option in principia, and make that orbit stay in the expected limits for 10 s, the contract will get completed - even if the values change in those 10 s, they just need to remain in limits.

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Hi guys!

I have a suggestion for you.
Is there a way to implement a close (x) button on top right of each page opened? Like a windows form.

When we have some Principia windows opened, we can only close each by clicking again on the button that opens that particular window.
Finding that button make me strugle some times, mostly when I have many Windows open and they are all over each other. I think this close button as a handling facilitator for the system.

Hope its a valid suggestion :blush:, it's not much, but it's honest work. lol

 

Take care of yourselves and your families.

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On 5/24/2020 at 3:13 PM, gsantos9489 said:

Is there a way to implement a close (x) button on top right of each page opened? Like a windows form.

Hope its a valid suggestion :blush:, it's not much, but it's honest work. lol

It's a perfectly valid suggestion, in fact it has been suggested before, see #2295.  With any reasonable GUI system it would be a 10-minute fix, but not so with Unity's GUILayout which doesn't support such an advanced UI feature.  We'd need to program it ourselves and even so it couldn't be on the title bar but it would have to be in the window pane itself, which would probably look odd, and require some repositioning of the current UI elements.

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On 5/25/2020 at 2:23 PM, pleroy said:

It's a perfectly valid suggestion, in fact it has been suggested before, see #2295.  With any reasonable GUI system it would be a 10-minute fix, but not so with Unity's GUILayout which doesn't support such an advanced UI feature.  We'd need to program it ourselves and even so it couldn't be on the title bar but it would have to be in the window pane itself, which would probably look odd, and require some repositioning of the current UI elements.

I understand. Well hope there is a way to implement it without any major issue or mess in the layout in the future.

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Posted (edited)
On 5/22/2020 at 4:51 AM, eggrobin said:

For the new moon (lunation number 252), the new release (Fuchs) is out.

  • The issues with rotation (uncontrolled spin-up, jerky motion, oscillations, etc.) introduced in Frobenius and Fubini have for the most part been solved. We are aware of one remaining case of aberrant spin-up, reported by @scimas, but this seems to be a very rare issue at this point.
  • Prior to ignition, the manœuvre node marker on the navball for guided burns now points to the orientation at ignition, instead of following the current Frenet frame. This is more useful for manual burns (the spacecraft can be oriented correctly prior to ignition, instead of having to be guided even before the manœuvre starts). Perhaps more importantly, in conjunction with change MuMech/MechJeb2#1264 (available in MechJeb dev builds ≥ 958), this means that MechJeb can execute all Principia manœuvres.
  • New APIs have been added for use by @Sir Mortimer’s KerbalismContracts.

See the change log for more details.

We support two sets of versions of KSP: downloads are available for 1.9.1 & 1.8.1, and for 1.5.1, 1.6.1, 1.7.x. Make sure you download the right one (if you don't, the game will crash on load).

For the convenience of our Chinese users, the binaries can be downloaded either from Google Drive or from 腾讯微云.

This is the last release to support KSP 1.5.1, 1.6.1, and 1.7.x, as Realism Overhaul and Real Solar System now support 1.8.1.

请问能不能先不要不更新1.7.x的?作为RP-1的一个Recommend Mod,RSSVE现在只支持1.7.3,而且RP-1还有好多Recommend Mod未在1.8和1.9下有过测试是否可以正常运行

或者实在不行的话在比较醒目的位置留下一个1.7.x的下载链接也好,谢谢

Edited by Peter JY
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24 minutes ago, Peter JY said:

请问能不能先不要不更新1.7.x的?

We typically move forward as soon as RSS/RO/RP-1 is available for a version.  We cannot keep supporting old versions forever.  If you absolutely want to stick to 1.7.x, you'll have to stick to Fuchs.

25 minutes ago, Peter JY said:

作为RP-1的一个Recommend Mod,RSSVE现在只支持1.7.3

Fine, but this is an RSSVE problem, not a Principia problem: there are hundreds of mods around and we cannot track everyone of them.  Have you opened an issue on RSSVE asking them to recompile for 1.8.1?  No you haven't.

14 hours ago, sonionoff said:

can you tilt stock planets with principia?

You can, but you'll need to do some work.  There is a configuration file for that.  There was also a discussion earlier on this thread.

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Posted (edited)

Hello!

Is it possible to plan flight before i build and launch vessel? And use this plan total delta-v for building.

Or I have to export current planet positions and velocities to file and use some extra software to calculate?

Flight plan button is unavailable in tracking station

 

Edited by VladTs
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23 hours ago, Xander el interplanetario said:

''fatou'' version for my game

I keep them around as well since KerbalEDU still has not updated past 1.4.5 so links are in the spoiler below.

Please Note: The Principia team does tons of amazing great work on this mod & needs to focus on newer KSP versions (which I very much endorse since KSP1.8+ handle large craft better :-).

so please remember that those of us who continue to use fatou are 'on our own' = no support.  You may also want to save copies for yourself of the current Fuchs since it is also "the last release to support KSP 1.5.1, 1.6.1, and 1.7.x"

 

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1 hour ago, AloE said:

I keep them around as well since KerbalEDU still has not updated past 1.4.5 so links are in the spoiler below.

Please Note: The Principia team does tons of amazing great work on this mod & needs to focus on newer KSP versions (which I very much endorse since KSP1.8+ handle large craft better :-).

so please remember that those of us who continue to use fatou are 'on our own' = no support.  You may also want to save copies for yourself of the current Fuchs since it is also "the last release to support KSP 1.5.1, 1.6.1, and 1.7.x"

 

THANKS <3

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@pleroy Is VesselGetPosition only supposed to give past positions? I'm extremely new to modding (even using C# at all), so I could be doing something wrong. But passing a time not in the past (eg Planetarium.getUniversalTime() + non_negative_number) throws out of range error. If it isn't supposed to work like this, I will open an issue on github.

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Predictions are predictions, they come with a lot of fine print (beyond the obvious impossibility of actually predicting the future in the presence of a player, computing the future in the same way as we compute the past would be prohibitively slow, so that the predictions are approximate; this means that you need to supply additional data on how accurate you want them, computing them may require lengthening the ephemeris which can be expensive, etc.).

External APIs with a lot of parameters and a lot of fine print mean more work, not just to implement them, but to maintain them in the years to come. VesselGetPosition was added for a specific use case in @Sir Mortimer's KerbalismContracts, whose design is, while not wholly dependent on Principia, at least highly aware of its existence. For that use case, past positions were enough.

What is your use case?

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I'm writing an addon for kOS. Since the trajectory of the vessel doesn't match patched conics in the presence of N-body gravitation (especially body to body transfer trajectories), automatic accurate execution of manoeuvre nodes becomes impossible. If instead I can get position from Principia, I can code the execution program to seek a certain distance from some body at a certain time (within some margin, not pin point accurate). So it would be helpful if principia could provide the prediction.

For my use case it would be enough to get predictions that fit in the constraints provided in the principia settings. That is, the future time doesn't have to be arbitrarily large, only as far as the map view trajectory goes, similarly for the error in prediction.

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2 minutes ago, scimas said:

I'm writing an addon for kOS. Since the trajectory of the vessel doesn't match patched conics in the presence of N-body gravitation (especially body to body transfer trajectories), automatic accurate execution of manoeuvre nodes becomes impossible. If instead I can get position from Principia, I can code the execution program to seek a certain distance from some body at a certain time (within some margin, not pin point accurate). So it would be helpful if principia could provide the prediction.

For my use case it would be enough to get predictions that fit in the constraints provided in the principia settings. That is, the future time doesn't have to be arbitrarily large, only as far as the map view trajectory goes, similarly for the error in prediction.

In order to interact with manoeuvres you would also need an API for that; perhaps you may want to resurrect something like https://github.com/mockingbirdnest/Principia/issues/2144 (and to talk to @Butcher, who has worked on that and may have some useful insights, about it).

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The manoeuvre (the current one) can already be accessed through kOS. That issue was about exposing a lot of the FlightPlanner, but as @Butcher said, most of the proposed things can already be accessed through the stock api. He had also written the kOS side of the code for the hypothetical principia interface at the time. I found out the "history only" part about VesselGetPosition when I was working on my modification of his code. The problem I'm trying to address is a lack of future trajectory prediction (both position and velocity) in the presence of N-body gravitation.

Edited by scimas
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  • eggrobin changed the title to [WIP][1.8.1, 1.9.1, 1.10.1] Principia—version Гельфанд, released 2020-11-15—n-Body and Extended Body Gravitation, axial tilt

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