eggrobin

[WIP][1.5.1, 1.6.1, 1.7.x] Principia—version Fourier, released 2019-10-28—n-Body and Extended Body Gravitation, axial tilt

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Posted (edited)
7 hours ago, Clockwork13 said:

Does anyone happen to have a download link to the 1.3.1 version of this mod anywhere?

https://bit.ly/2W2wkDx

Edited by Agustin

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@eggrobin @pleroy It is possible that the "switch vessel" option for targets is broken in ferrari. It just crashed my game twice in a row (or so I assume).

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1 hour ago, Delay said:

@eggrobin @pleroy It is possible that the "switch vessel" option for targets is broken in ferrari. It just crashed my game twice in a row (or so I assume).

It crashes for me too...

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Here is my FATAL:

Quote

    @   000007FEF1B6633A      google::LogMessageFatal::~LogMessageFatal [0x000007FEF1B66339+57]
    @   000007FEDC75474B      principia__HasVessel [0x000007FEDC75474A+314]
    @   000000001BE06634      (No symbol) [0x000000001BE06633]
F0828 20:48:32.533069  6908 interface.cpp:580] Check failed: 'plugin' Must be non NULL

 

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yes it crashed for me too once and just in case I didn´t use that feature anymore...

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Posted (edited)
On 8/20/2019 at 4:33 PM, pleroy said:

Nice!  Make sure that you send a pull request to the author of KerBalloons to move the fix upstream: the next user of KerBalloons and Principia will thank you.

The revised dll has been working well the past week or so of use so I created the relevant KerBalloons ReInflated pull request :-)

Also, since KerBalloons ReInflated v0.4.4 is released under MIT license at CurseForge, for anyone else interested in experimenting with KerBalloons ReInflated  & Principia (e.g. launching orbital or suborbital 'Rockoons' here is a link to just the '.Part' revised KerBalloons.dll (with the original License.txt) that I am using in place of the one included with the official download mod package at CurseForge until an official update were to be made for v.0.4.4+.

For example, launch a nanosat into orbit via a Rockoon:

Ly81V0d.jpg
Edited by AloE
mod name & links

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8 hours ago, Agustin said:

yes it crashed for me too once and just in case I didn´t use that feature anymore...

Well, this is not how bugs get fixed :rolleyes:

I have created #2313 to track this bug.

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For the new moon (lunation number 243), the new release (del Ferro) is out.

  • Higher degree and order gravity models have been added for Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune; satellites of these planets will now have more realistic motion (this change only takes effect on new saves)
  • Some bugs reported by @Sir Mortimer, @scimas, and @Kobymaru have been fixed.

 See the change log for more details.

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

 

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On 8/28/2019 at 8:08 AM, That John said:

does this mod add such things as orbital decay? if so im getting it

AFAIK no, no orbital decay. Satelite in LKO/LEO will stay there forever(~150 earth years in RSS 300x400km orbit is  "forever"-yes, I was bored)

BUT, Mechjeb and Kerbal engineer are unaware of Principia, therefore orbit parameters reported by them will change in time, especially for higher orbits. 

 

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On 9/7/2019 at 7:17 PM, gsantos9489 said:

There is a way where  I can add/change the axial tilt manually for an special planet?

Yes, you'll need to write a suitable configuration file.

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5 hours ago, pleroy said:

Yes, you'll need to write a suitable configuration file.

Thanks @pleroy ! ! !

I was searching for this a couple days :D

 

Edit:

I'm reading the link you sent me, but can't found which property into the configuration file we should use to set the Axial Tilt Angle.

Do you happen to know which property has to be set in this particular case?

Edited by gsantos9489
Doubt on the configuration file.

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Hi !

I have a little technical question about Principia.

I trie to make it work on KSRSS or SSRSS (I want play on a real solar system size 2.5) (I couldn't instal RSS 2.5, I don't know why it doesn't work)

When I delete the planets which are note supported by principia I can launch the game without crash and I have the good principia interface.

But since a rocket lift off, it instantanly explode due to too high G.

Since Principia work on RSS I guess there is no reason to don't make it work on SSRSS or KSRSS...

Anyone could help me on this problem ? 

Thanks for your help ^^ 

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On 9/11/2019 at 8:05 AM, Carni35 said:

Since Principia work on RSS I guess there is no reason to don't make it work on SSRSS or KSRSS...

RSS parameters are different from SSRSS..changing the parameters of the celestial bodies in a system basically changes the whole dynamic...fyi see...

On 2/4/2014 at 7:19 PM, eggrobin said:

Since Principia makes all bodies attract each other according to Newtonian gravitation, the stability of the solar system is a concern; when using stock KSP, Principia modifies the Jool system so that it is stable. When using a customized system (e.g. with Kopernicus), you need to make sure that the system is stable.

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On 9/11/2019 at 2:18 AM, gsantos9489 said:

I'm reading the link you sent me, but can't found which property into the configuration file we should use to set the Axial Tilt Angle.

Do you happen to know which property has to be set in this particular case?

A single angle is not enough to describe how a planet is oriented (this requires three degrees of freedom), nor even how its axis is oriented (two degrees of freedom).

You may find it useful to read the section on the semantics of the quantities used for body rotation, and to look at the figure referenced therein, to understand how to properly describe the orientation of a planet.

The section on the principia_gravity_model configuration will then tell you how to specify that information in the configuration file.

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15 hours ago, eggrobin said:

A single angle is not enough to describe how a planet is oriented (this requires three degrees of freedom), nor even how its axis is oriented (two degrees of freedom).

You may find it useful to read the section on the semantics of the quantities used for body rotation, and to look at the figure referenced therein, to understand how to properly describe the orientation of a planet.

The section on the principia_gravity_model configuration will then tell you how to specify that information in the configuration file.

Thanks.

Eureka, I didn't noticed that more than one angle is necessary to tilt a planet, now all (the documentation) makes sense :o ! ! !

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For the new moon (lunation number 244), the new release (Fibonacci) is out.

  • An orbit analysis tool has been added which computes mean elements and orbit recurrence properties. This has been in the works since February; more features will be added at a later date, e.g., mean solar times of ascending nodes (for controlling sun-synchronicity). See below for a screenshot of the orbit analysis tool in action on a Молния orbit. The tool is fairly complex; documentation will be provided soon.
    65556361-96ebbf00-df2f-11e9-8142-5a1dcd0
  • A crash reported by @Delay has been fixed.
  • A dependency issue that would prevent Principia from starting has been fixed.

 See the change log for more details.

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

Edited by eggrobin

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awesome update @eggrobin!!! looking forward to using the new tool (and humbly awaiting documentation to fully grasp all the information it provides)! thanks for your work!

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On 9/29/2019 at 12:37 AM, eggrobin said:

The tool is fairly complex; documentation will be provided soon.

The documentation is here: https://github.com/mockingbirdnest/Principia/wiki/Orbit-analysis.

It includes some background information on frozen orbits and ground track recurrence, as well as many examples based on real-life satellites to illustrate the underlying concepts.

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On 3/15/2018 at 10:44 PM, pleroy said:

We don't think there are any issues related to the DLC, vessels appearing are already handled by Principia.

I have been using Principia with 1.7.3 & RSS/RVEx64/ro.  Which has led me to want to setup in that environment vessels on Jovian, Saturnian moons & start to compare orbit characteristics/opportunities with vessels planted in various location on various TRAPPIST-1 for Principia planets.  Getting them there from Earth or Trappist1e would be quite a challenge I would prefer to avoid (for now at least) since my focus on the moment is more to experiment with the orbital behavior of vessels launching from various locations of interest rather than how to get them to that location (the goal being 'discover' launch locations with interesting launch/orbit characteristics through 'try it experimentation' which works better for the age group I am working with...)

I was hoping that 'landed state vessels appearing' is something still handled ok by Principia (since this would make it vastly easier to trial ideas since there are so many differences between the systems with which for me to begin to get familiar to even find interesting cases to clean up to show kids.

I use the word 'injected' below because I have not figured out a current way I am going to move/'teleport' the 'landed' vessel(s) yet...I have seen @eggrobin indicate in prior posts that teleportation (E.G. HYPER EDIT) breaks things though I am hoping that the specific case of 'teleporting' a 'landed state' vessel going to the surface of a different celestial might overcome breaking Principia calculations??? ...since I can not seem to have Principia generate the celestial state for a .sfs created with the DLC Mission Builder...I'm going to first try plugging in Lat, Lon, Alt, rotation data discovered via the mission builder in to the vessel configuration of a vessel  opened in a .sfs save generated by Principia...Looking at the vessel info in the .sfs created by Mission Builder v Principia led me to the following question:

Please let me know if there are  obvious major obstacles you see that make this idea above rather unfeasible.  For example, is my conceptual thinking even valid that a 'landed state vessel' might be treated as a new starting point for Principia iterations for that vessel such that if I can figure out how to inject that vessel at the various lat, lon, alt, rotation values I desire as 'landed' on  the various celestial bodies then Principia would actually generate its intended model going forward fr that vessle after launch from the new location...or for example is there information stored in the save or with the ship by Principia or KSP that would make a landed vessel  snipped from Earth or Trappist 1e and then injected as landed on the surface on another body in that system (e.g. Io, Mimus, Trappist-ih, etc...) that would now be garbage/incorrect data' that would not be purged & would corrupt on going future calculations by Principia for that ''injected' vessel when launched from the new 'injected/teleported' landed state location?

Thank you very much for your insights! 

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@AloE, not exactly what you intend to do, but I had a similar situation going on when I originally discovered Principia. I had a pretty advanced savegame with many satellite relays, in-orbit stations, etc. I wanted to keep these. I ended up creating a fresh install without Principia, loading up all vessels in a new savegame, Hyper-editing them to their appropriate orbits, and finally installing Principia on top of this install after every ship was in place. In your case, you could Hyper-edit them to orbit and then use the mod's Ship Lander functionality. 

I had no trouble whatsoever using the aforementioned method, however please note there were no landed vessels involved in the exercise.

 

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On 10/23/2019 at 7:03 PM, hypervelocity said:

finally installing Principia on top of this install after every ship was in place

Thank you for sharing your historical observation...interesting to me that you were able to apply Principia 'on top' after everything was in place: I am curious was that with 1.3.1 or earlier & Kerbol system or RSS?  Principia's generation of the state of the celestial system always had me thinking in terms of always using a save that Principia generated from the start...for example, with Principia already loaded/active in KSP 1.3.1 I also did use HyperEdit at that time to place the 'mun craft' into orbit to replicate eggrobin's "Mun tutorial"  Though I stopped using hyper edit after reading the following post from eggrobin earlier this year:

 

On 4/1/2019 at 1:43 AM, eggrobin said:

These mods typically interact very poorly with Principia, as a core principle of Principia is to keep an internal model of where things are, and adjusting their in-game positions and velocities accordingly: this is how Principia can perform high-order symplectic integration even though the physics engine only does explicit Euler (which is a first order nonsymplectic method), and it is how it enforces conservation of momentum.

Mods that try to change the orbit without going through Part.AddForce and the like have, at best, no effect (this is in particular the case of HyperEdit itself, which cannot be used to move vessels around when using Principia).

So far on the current objective:  using the DLC Mission Builder for 1.7.3 I did place a test craft at a test location on Mimus & then had the Mission Builder generate a .sfs file with that craft located on Mimus.  Then I cut/paste the following FLIGHTSTATE data segments for the Mimus vessel from the Mission Builder .sfs  into a .sfs created new with Principia & the same 'Mimus test' craft opened in the VAB & sent to the launchpad at the Earth KSC launchpad.

Spoiler

            landedAt = Mimas
&
			lat = -84.151312274149291
			lon = -60.236176396947741
			alt = 6018.5465949220525
			hgt = 25.4615517
			nrm = -0.0438912883,0.994534552,-0.0947307348
			rot = -0.963509262,-0.00347075728,-0.263180286,0.0487231016
			CoM = 0.00571703911,-15.3015165,-0.00210547447
&
ORBIT
			{
				SMA = NaN
				ECC = 1
				INC = 84.151287377200788
				LPE = 90
				LAN = 210.00518813712469
				MNA = 0
				EPH = 54.700000000002952
				REF = 17
				IDENT = Mimas
			}

 

This did result in the craft no longer being on Earth at the KSC launchpad, instead it was now at the at the expected position & orientation on Mimus (= same location & orientation as where I put it using the DLC Mission Builder).  At launch, Principia does appear to now manage this vessel in the 'adjusted' Principia generated .sfs save & I only see this info log in glog...no error or warning logs for today's date:

tlmKKtA.png sTdTdlS.png KLT1hib.png

Where as the launching the same vessel in the Mission Builder .sfs save from which I copied the above data results in the 'DLC mission handler' taking over the save such that Principia does not, and looking at missing icons/features apparently a bunch of other mods do not, run in the "DLC Mission gameplay state":

Y1kRo9N.png

I would be grateful to hear from @pleroy or @eggrobin if they foresee any issues with my 'cut & paste' method described above before I populate the various systems with vessels...

[ for the kids (& i ) to explore/compare with... or maybe for them to just laugh at my lack of focus on staging as they fix heat shields & parachutes from flying away at second stage ignition...since the guinea-pig for the above process seemed to enjoy laughing as much while showing me how the ship would fall apart when they staged & crash into Saturn because they could not shutdown the solid rocket design &)  & I was over ruling their choice to burn prograde again...as they enjoyed rising out of a Mimus crater to see 'Saturn rise' & pass over the rings and burn up 'Cassini like' ...lol]

Thanks! :-)

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3 hours ago, AloE said:

Thank you for sharing your historical observation...interesting to me that you were able to apply Principia 'on top' after everything was in place: I am curious was that with 1.3.1 or earlier & Kerbol system or RSS?

Correct - the aforementioned was a KSP 1.3.1 install with Realism Overhaul, RP-0 & Real Solar System (plus dependencies, suggested and recommended mods). All mods were installed via CKAN; after that, vessel files were copied over, loaded into the new installation, placed throghout the solar system via Hyper Edit, and finally Principia was installed on top. No issues whatsoever in this procedure.

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