[WIP][1.8.1, 1.9.1, 1.10.1, 1.11.0–2, 1.12.2–5] Principia—version ‎‎Kronecker, released 2024-11-01—n-Body and Extended Body Gravitation

[mariusvnh]

Please make 1.7 support, you're the bests !

[pleroy]

On 4/23/2019 at 11:03 AM, mariusvnh said:

Please make 1.7 support, you're the bests !

We won't have 1.7 support in the May version (Fáry, May 4).  Barring the unexpected we should have it in the June version (Fatou, June 3).

[Krzysztof z Bagien]

Hi, long time reader, first time poster here.
This mod is great, but I have one big gripe with it: sliders. Would you consider adding something different than those sliders to adjust maneuver deltaV, time, etc.? Sliders look like a good idea at first, but I find them really cumbersome and it takes a lot of time to get what I want with them. Something like in Maneuver Node Evolved manual deltaV input window would be way easier and convenient to use.

https://www.curseforge.com/kerbal/ksp-mods/maneuver-node-evolved

[pleroy]

1 hour ago, Krzysztof z Bagien said:

This mod is great, but I have one big gripe with it: sliders. Would you consider adding something different than those sliders to adjust maneuver deltaV, time, etc.? Sliders look like a good idea at first, but I find them really cumbersome and it takes a lot of time to get what I want with them.

The next version (May 4) will have text entry fields in addition to sliders for the Δv and time.

1 hour ago, Krzysztof z Bagien said:

Something like in Maneuver Node Evolved manual deltaV input window would be way easier and convenient to use.

Not familiar with that mod, but it does look cool.  Snapping manoeuvre nodes to "interesting points" of the trajectory is something we have in mind, but it's far from trivial.

[Delay]

3 minutes ago, pleroy said:

Snapping manoeuvre nodes to "interesting points" of the trajectory is something we have in mind, but it's far from trivial.

I believe you're referring to multiple maneuver node editing here? The problem of "What controls the timewise placement of a maneuver?".
Why not determine the time of a maneuver based on previous nodes? As in "Maneuver 2 is 4 hours after maneuver 1"?

 

I realize the problem is probably more difficult than that, but that's my suggestion. Probably has already been looked at anyways.

[pleroy]

1 minute ago, Delay said:

I believe you're referring to multiple maneuver node editing here?

I was referring to the fact that Maneuver Node Evolved apparently let you snap a manoeuvre to the apoapsis or to the closest approach, etc., which would remove quite a bit of annoying hand-tuning.

1 minute ago, Delay said:

The problem of "What controls the timewise placement of a maneuver?".
Why not determine the time of a maneuver based on previous nodes? As in "Maneuver 2 is 4 hours after maneuver 1"?

Yes, this is what we'll do in the next version, if only because editing the field that counts down was not going to work.  As for editing multiple manoeuvres, it's something that I'd like to do but it goes pretty deep.

[RocketSquid]

Okay, a few questions, since I know adding principia to an existing save will break it.

1. Will removing principia from a save break it to the extent that adding it does, or will the issues be less severe?

2. Will deleting and reinstalling principia (in order to update it) without opening the save in between break the save?

[pleroy]

6 hours ago, RocketSquid said:

Okay, a few questions, since I know adding principia to an existing save will break it.

1. Will removing principia from a save break it to the extent that adding it does, or will the issues be less severe?

The issues should be more-or-less the same: the planets and vessels will be at semi-random locations.

6 hours ago, RocketSquid said:

2. Will deleting and reinstalling principia (in order to update it) without opening the save in between break the save?

This will have no effect other than upgrading Principia.  The saves will remain compatible (we maintain compatibility for years).

[Flibble]

Hello Principians,

I'm looking to integrate Principia's flight planning into my kOS based flight computer. I noticed that the API isn't implemented yet according to: https://github.com/mockingbirdnest/Principia/wiki/Interface-for-other-KSP-mods

Is there any WIP code for this? Or should I just crack on and write it myself? I'm happy to do that, but would rather not duplicate existing work if there is some.

[pleroy]

1 hour ago, Flibble said:

Hello Principians,

I'm looking to integrate Principia's flight planning into my kOS based flight computer. I noticed that the API isn't implemented yet according to: https://github.com/mockingbirdnest/Principia/wiki/Interface-for-other-KSP-mods

Is there any WIP code for this? Or should I just crack on and write it myself? I'm happy to do that, but would rather not duplicate existing work if there is some.

The comment on top of that page is outdated: I just removed it.  The API is available starting with Fano.  Note that as things stand it only gives you the parameters of the geopotential model.  If you have other needs we would like to hear from them to understand how to best address them.

[Flibble]

25 minutes ago, pleroy said:

The comment on top of that page is outdated: I just removed it.  The API is available starting with Fano.  Note that as things stand it only gives you the parameters of the geopotential model.  If you have other needs we would like to hear from them to understand how to best address them.

I'd like to be able to read the flight planning data, e.g. time to next manoeuvre, direction, etc. This seems to be available via the interface already, but not exposed to C#. I was looking at just calling the dll exports directly, but adding them to the external interface seems a neater way to do it.

[pleroy]

5 minutes ago, Flibble said:

I'd like to be able to read the flight planning data, e.g. time to next manoeuvre, direction, etc. This seems to be available via the interface already, but not exposed to C#. I was looking at just calling the dll exports directly, but adding them to the external interface seems a neater way to do it.

The external interface is the only API where we will guarantee stability and compatibility.  The rest is entirely internal and should not be used by other mods.  Can you open an issue on GitHub to track this?

[Flibble]

35 minutes ago, pleroy said:

The external interface is the only API where we will guarantee stability and compatibility.  The rest is entirely internal and should not be used by other mods.  Can you open an issue on GitHub to track this?

I have opened an issue.

[hypervelocity]

On 4/25/2019 at 5:59 PM, pleroy said:

The next version (May 4) will have text entry fields in addition to sliders for the Δv and time.

these are great news @pleroy!!! I was really expecting this feature to be added as complex/long flight plan are really sluggish on my PC! 

thank you & the team in advance!!!!

[Nikola]

Does Principia have any compatibility with kOS? Writing scripts to allow probes to autonomously execute maneuvers is very appealing, and also realistic. Really all you would need is some way to make the maneuver nodes in the flight planner visible to kOS for maneuver vector and node ETA.

Edited May 3, 2019 by Nikola

[Flibble]

1 hour ago, Nikola said:

Does Principia have any compatibility with kOS? Writing scripts to allow probes to autonomously execute maneuvers is very appealing, and also realistic. Really all you would need is some way to make the maneuver nodes in the flight planner visible to kOS for maneuver vector and node ETA.

Currently no. I've not had a chance to look at it yet (and I assume no one else has), not least because I can't build Principia on my work PC, which is where I do most of my dev.

[Nikola]

Ah, well if you ever do get a chance I think it would be a pretty awesome addition. I did at least find a way to use kOS and Principia together for fairly precise maneuver execution, thanks to a quirk they both seem to share. You can use the kOS terminal and the flight planner while the game is paused, so its just a matter of planning a maneuver, pausing the game and then manually entering the burn time and ETA from the flight planner into the kOS terminal, and into the script. In this way you end up with accurate timing, and hopefully this may help people trying to do what I was.

Edited May 3, 2019 by Nikola

[scimas]

15 hours ago, Nikola said:

Ah, well if you ever do get a chance I think it would be a pretty awesome addition. I did at least find a way to use kOS and Principia together for fairly precise maneuver execution, thanks to a quirk they both seem to share. You can use the kOS terminal and the flight planner while the game is paused, so its just a matter of planning a maneuver, pausing the game and then manually entering the burn time and ETA from the flight planner into the kOS terminal, and into the script. In this way you end up with accurate timing, and hopefully this may help people trying to do what I was.

I've been doing this for a long time. 

In fact you don't even need to enter the burn time manually. Grab the manoeuvre node from kOS, get its deltaV, and eta. Then invert the rocket equation for expected change in mass and get the burn time by dividing the mass change by the burn rate of your engine (properly weighed by thrust and Isp in case of multiple engines). 

The only thing you have to take care of is that Principia shows deltaV to a ridiculous accuracy, 0.001 m/s, far more than kOS can achieve - at least at full thrust. 

Edit: There is already an issue open on github to provide more external API for modders. 

Edited May 4, 2019 by scimas

[Nikola]

2 hours ago, scimas said:

I've been doing this for a long time. 

In fact you don't even need to enter the burn time manually. Grab the manoeuvre node from kOS, get its deltaV, and eta. Then invert the rocket equation for expected change in mass and get the burn time by dividing the mass change by the burn rate of your engine (properly weighed by thrust and Isp in case of multiple engines). 

The only thing you have to take care of is that Principia shows deltaV to a ridiculous accuracy, 0.001 m/s, far more than kOS can achieve - at least at full thrust. 

Edit: There is already an issue open on github to provide more external API for modders. 

I tried grabbing info about the node but the main issue is that for maneuvers planned in the Principia flight planner kOS cannot see them, and returns an error that no maneuver nodes are present when they are. If you found a way to make the two work together I would be interested.

Edited May 4, 2019 by Nikola

[eggrobin]

For the new moon (lunation number 239), the new release (Fáry) is out.

• The UI now scales according to the KSP UI scale settings, and has been made a little more compact;
• those flight plan settings that are controlled by a slider can now also be edited by text entry (this includes the Δv components and timing of manœuvres);
• the TRAPPIST-1 patch has been updated for @GregroxMun’s SLIPPIST-1 v0.7.x.

 See the change log for more details.

We support two sets of versions of KSP: downloads are available for 1.4.x, 1.5.1, & 1.6.1, and for 1.3.1. Make sure you download the right one (if you don't, the game will crash on load).

 

[scimas]

10 hours ago, Nikola said:

I tried grabbing info about the node but the main issue is that for maneuvers planned in the Principia flight planner kOS cannot see them, and returns an error that no maneuver nodes are present when they are. If you found a way to make the two work together I would be interested.

You probably aren't activating "Show on navball" in the flight planner. That generates a continuously updating stock manoeuvre node. No Δv tracking though, that you have to do on your own. 

[Nikola]

11 hours ago, scimas said:

You probably aren't activating "Show on navball" in the flight planner. That generates a continuously updating stock manoeuvre node. No Δv tracking though, that you have to do on your own. 

Oh I see now, that was the problem. Thanks!

[Krzysztof z Bagien]

On 5/4/2019 at 2:26 PM, eggrobin said:

• The UI now scales according to the KSP UI scale settings, and has been made a little more compact;

It would be nice to set that separately. I have KSP interface scaled up (120% I belive), but would like Principia windows to be smaller - they are already quite big, and now main window and flight plan with single maneuver take half of my 1920x1080 screen

[pleroy]

On 5/6/2019 at 9:14 PM, Krzysztof z Bagien said:

It would be nice to set that separately. I have KSP interface scaled up (120% I belive), but would like Principia windows to be smaller - they are already quite big, and now main window and flight plan with single maneuver take half of my 1920x1080 screen

The two scales are multiplicative so setting the App Scale to 83% would cause the Principia window to go back to the normal size.  It seems that at least some mods do it that way.  Of course, it's hard to know if it's how Squad intended it...

Edited May 8, 2019 by pleroy

[N9 Gaming]

There appears to be a bug with Firespitter's "AddForceAtPosition" that makes 'Airplane Plus' helicopter rotors provide 0 lift with Principia instaled. FYI!

https://youtu.be/ycFx_OzQz3A

Edited May 9, 2019 by N9vaivie
Discovered Firespitter bug