[old thread] Trajectories : atmospheric predictions

[MaxZhao]

On 14/03/2017 at 8:28 PM, Youen said:

That's a bit of an overstatement... Unless you mean my code is so awful that no one can understand it ;-)

Unfortunately, I've lost interest in KSP in general for quite some time now, and I don't really want to reinstall the latest version just to fix bugs and upgrade code for the latest version, which is precisely the part I dislike about modding.

Maybe I'll get back to it later, but no ETA nor promises.

In the meantime, I can at least update the opening post inform people of what works or not, and on which version of the game. I think the most problematic issue is that prediction is not accurate, but I don't know what is the last version of KSP for which it worked correctly?

Also, despite what @Kobymaru says, I'm sure there are a lot of people around here that are able to improve the mod (starting with himself). And I'd be happy to release the work of anyone who would like to fix the issues / improve the mod. I can also give direct access to spacedock and AVC, and I think moderators can transfer the opening post ownership, or failing that we could create a new thread, if someone wants to maintain the mod.

I'm really sorry to "let down" the current users of the mod, but fixing this kind of issue can be cumbersome, and I don't want to force myself to do it if I'm not even going to play the game after that.

 

Many thanks for making it clear for everybody, hope everything goes well with your life!

[09gara]

I am getting an issue.  The issue is that the configuration window does not appear in map view when i right click the trajectories button on blizzy's toolbar.  I do get a very small grey rectangle in the upper left corner of the screen though, its about he size of my mouse cursor, so no idea what thats about.

[Kobymaru]

On 20.3.2017 at 1:42 AM, 09gara said:

I am getting an issue.  The issue is that the configuration window does not appear in map view when i right click the trajectories button on blizzy's toolbar.  I do get a very small grey rectangle in the upper left corner of the screen though, its about he size of my mouse cursor, so no idea what thats about.

Can you try deleting your \GameData\Trajectories\Plugin\PluginData\Trajectories\config.xml ?

[09gara]

Unfortunately Kobymaru deleting the config did not work, same problem.

[lajoswinkler]

Any chance of seeing the landing cross outside map view? Precision of the map view is quite low.

[mark7]

I have some trouble here when using trajectory with RSS. It says “prediction stop, too many iterations” 

Did I use this mod incorrectly or something else?

[dlrk]

Hey, quick note about the accuracy bug:

I've been using Trajectories with the latest FAR dev build, and my accuracy is just about perfect (got to the KSC runway from Munar orbit)

[Kobymaru]

On 20.3.2017 at 1:42 AM, 09gara said:

I am getting an issue.  The issue is that the configuration window does not appear in map view when i right click the trajectories button on blizzy's toolbar.  I do get a very small grey rectangle in the upper left corner of the screen though, its about he size of my mouse cursor, so no idea what thats about.

On 29.3.2017 at 4:55 AM, 09gara said:

Unfortunately Kobymaru deleting the config did not work, same problem.

I can't reproduce this on a fresh install. Could you do the following for me?

1. Zip up your GameData/Trajectories directory
2. Upload it somewhere, and send me the link
3. Delete your Trajectories directory
4. Reinstall Trajectories

 

On 2.4.2017 at 4:29 AM, lajoswinkler said:

Any chance of seeing the landing cross outside map view? Precision of the map view is quite low.

Very small chance, unless a kind Person implements it and submits a PR for me. However, I am looking into allowing the Trajectories window outside the Map view, which will allow you to use targeting to at least give you a distance from predicted impact to target

 

On 3.4.2017 at 11:56 AM, mark7 said:

I have some trouble here when using trajectory with RSS. It says “prediction stop, too many iterations” 

Did I use this mod incorrectly or something else?

In order to preserve your framerate, Trajectories does not calculate your trajectory endlessly. If your reentry is very flat and the trajectory is long, calculation will abort at a certain point. You can fix this by either flying a steeper descent or Going into Settings and Setting "Max Patches" and/or "Max frames per patch" higher. Prepare for FPS loss, though.

 

On 8.4.2017 at 9:05 PM, dlrk said:

I've been using Trajectories with the latest FAR dev build, and my accuracy is just about perfect (got to the KSC runway from Munar orbit)

Thanks, good to know! That means that the issue is buried somewhere in the force calculation for stock. Help still wanted, guys!

Edited April 10, 2017 by Kobymaru

[dlrk]

Kobymaru, about Lajoswinkler's suggestion:

I understand that it might be difficult/time consuming to implement the graphical display in the flight view, but I have a suggestion that would be VERY useful, and that I don't THINK would be too difficult:

Allow access to the Trajectories window in Flight view and provide distance from target laterally, longitudinally, and total. Also, and this probably a more difficult suggestion, but if possible, I'd appreciate it, link the trajectories target with a target selected from Scansat or Mechjeb.

Any thoughts on this getting implemented?

[Kobymaru]

14 hours ago, dlrk said:

Kobymaru, about Lajoswinkler's suggestion:

I understand that it might be difficult/time consuming to implement the graphical display in the flight view, but I have a suggestion that would be VERY useful, and that I don't THINK would be too difficult:

You're right, it would be useful. I'll take a look, if we're lucky the changes are small. No promises.

14 hours ago, dlrk said:

Allow access to the Trajectories window in Flight view and provide distance from target laterally, longitudinally, and total.

This is not a priority for me. Please take a look at the function Trajectories.Util.distanceFromLatitudeAndLongitude(). If you provide me with the math to calculate North/East deviation, I will consider implementing it.

public static double distanceFromLatitudeAndLongitude(
  double bodyRadius,
  double originLatidue, double originLongitude,
  double destinationLatitude, double destinationLongitude)
{
  double sin1 = Math.Sin(Math.PI / 180.0 * (originLatidue - destinationLatitude) / 2);
  double sin2 = Math.Sin(Math.PI / 180.0 * (originLongitude - destinationLongitude) / 2);
  double cos1 = Math.Cos(Math.PI / 180.0 * destinationLatitude);
  double cos2 = Math.Cos(Math.PI / 180.0 * originLatidue);

  double lateralDist = 2 * bodyRadius *
    Math.Asin(Math.Sqrt(sin1 * sin1 + cos1 * cos2 * sin2 * sin2));

  return lateralDist;
}

Also, please don't forget that atmospheric entry doesn't just happen from low circular Kerbin Orbit with 0° inclination, it happens on different planets with different rotations, radii, different orbits with different inclinations.

For example, personally I'd prefer "Lateral Right" and "Longitudinal along the direction of motion" to "South" and "East", but that's just me. I guess South/East deviation would still be useful.

 

14 hours ago, dlrk said:

Also, and this probably a more difficult suggestion, but if possible, I'd appreciate it, link the trajectories target with a target selected from Scansat or Mechjeb.

Any thoughts on this getting implemented?

I'm afraid I'm not interested in this feature. If you code it yourself (and code it well), I will accept pull requests.

ps.: Please either quote me or use the @ tag like this: @dlrk . This way I get a notification whenever you post something that concerns me.

[dlrk]

@Kobymaru

Sorry about that. For some reason, I was under the impression that just typing someones name tagged them. Unfortunately, implementing this stuff myself is a bit beyond me. I wouldn't say I have no coding skills, but they're pretty limited. I certainly wish I could help though. I actually thought that Trajectories already calculated lateral and longitudinal deviation, since it appeared to me like that was what the navball overlay displayed graphically.

In any case, the only change that I would personally say is really important, and not just convenience issue, is access to the trajectories window in flight view. The rest is all nice to have, and I really hope you or someone else is able to implement it in the future.

Obviously, I appreciate the work you're doing on this add-on. This feature really should be stock, so thanks for picking up Squad's slack

[09gara]

@Kobymaru

I uploaded the trajectories install and the link is:

https://www.dropbox.com/s/zfd5r19d3ptaoyn/Trajectories.rar?dl=0

[SpaceOdissey]

On 24 de diciembre de 2014 at 5:12 PM, T.Lancer said:

it would be awesome if you could get it showing trajectories outside of the map view. like this:

That will change a lot this mod!

[linuxgurugamer]

On 4/11/2017 at 4:44 AM, Kobymaru said:

You're right, it would be useful. I'll take a look, if we're lucky the changes are small. No promises.

This is not a priority for me. Please take a look at the function Trajectories.Util.distanceFromLatitudeAndLongitude(). If you provide me with the math to calculate North/East deviation, I will consider implementing it.

public static double distanceFromLatitudeAndLongitude(
  double bodyRadius,
  double originLatidue, double originLongitude,
  double destinationLatitude, double destinationLongitude)
{
  double sin1 = Math.Sin(Math.PI / 180.0 * (originLatidue - destinationLatitude) / 2);
  double sin2 = Math.Sin(Math.PI / 180.0 * (originLongitude - destinationLongitude) / 2);
  double cos1 = Math.Cos(Math.PI / 180.0 * destinationLatitude);
  double cos2 = Math.Cos(Math.PI / 180.0 * originLatidue);

  double lateralDist = 2 * bodyRadius *
    Math.Asin(Math.Sqrt(sin1 * sin1 + cos1 * cos2 * sin2 * sin2));

  return lateralDist;
}

Also, please don't forget that atmospheric entry doesn't just happen from low circular Kerbin Orbit with 0° inclination, it happens on different planets with different rotations, radii, different orbits with different inclinations.

For example, personally I'd prefer "Lateral Right" and "Longitudinal along the direction of motion" to "South" and "East", but that's just me. I guess South/East deviation would still be useful.

 

I'm afraid I'm not interested in this feature. If you code it yourself (and code it well), I will accept pull requests.

ps.: Please either quote me or use the @ tag like this: @dlrk . This way I get a notification whenever you post something that concerns me.

Where is the repo you are using on Github?

There are some values I'd like to expose for use by the Suicide Burn mod, and I don't want to use Reflection

Thanks

[Kobymaru]

17 hours ago, linuxgurugamer said:

Where is the repo you are using on Github?

Considering that you already forked it, you found it

17 hours ago, linuxgurugamer said:

There are some values I'd like to expose for use by the Suicide Burn mod, and I don't want to use Reflection

Please expose them in Plugin/API.cs

[linuxgurugamer]

I have done it in API.cs

So far, it's a simple change to expose one value.  I have the suicide burn mod working, have a problem with atmosphere is, but know what to to.  Once I get it done, I'll push the changes to github 

 

[PiezPiedPy]

@Kobymaru

Should I PR the neuoy repository or your fork and who is releasing the official updates ?

Edited April 26, 2017 by PiezPiedPy

[Kobymaru]

7 hours ago, PiezPiedPy said:

@Kobymaru

Should I PR the neuoy repository or your fork

Doesn't really matter, but lets say that from now on, PR's should go to the original (neuoy) repository. I have merge priviliges there.

Quote

and who is releasing the official updates ?

I will be releasing the updates.

 

ps.: I am loving these changes. I'm going to do a thorough review (takes a bit of time) and I already have a few change request, otherwise it looks really good!

Edited April 26, 2017 by Kobymaru

[Kobymaru]

Pre-Release for the Pre-Release for all of you early birds:

https://github.com/neuoy/KSPTrajectories/releases/tag/v1.6.7-pre1

On 23.4.2017 at 3:33 AM, SpaceOdissey said:

That will change a lot this mod!

If you can get me the code of the mod featured in the video, it will increase the chances of implementation.

Spoiler

Like from 3.5% to 5%  

BTW, What increases the chances of implementation to 100% is if you implement it yourself.

Edited April 26, 2017 by Kobymaru

[Kobymaru]

On 18.4.2017 at 11:26 PM, 09gara said:

@Kobymaru

I uploaded the trajectories install and the link is:

https://www.dropbox.com/s/zfd5r19d3ptaoyn/Trajectories.rar?dl=0

I'm afraid I can't reproduce your issue. On my install (with your archive unpacked) the windows is in the upper left corner.

What I do see in your  \GameData\Trajectories\Plugin\PluginData\Trajectories\config.xml file , however, is this:

<ymax>-63554</ymax>

Something seems to be messed up here. Deleting this file should really fix the issue. If not, then I'm actually out of ideas. Sorry.

[linuxgurugamer]

@Kobymaru

I just did a PR for you, the change was done to expose the end time value in the API

[brymck]

Really love this mod, great for atmospheric landings back at Kerbin. One quick question, maybe I'm just not working out the execution path very well - any way to correct for deviations caused by decoupling? Most of my atmospheric landings in the latest version have required that I dump the engine/tank portion of, say, a Munar lander in favor of something more like a heat shield-y facing surface retrograde to have a less explosion filled landing experience. So, I get a good idea of where the entire craft would land, but then after decoupling it shifts drastically to the west. Basically I try to make my landing well to the east of KSC and the ejection force from the decoupling knocks the landing spot back west toward KSC, but it would be great to be as exact as possible with the process.

I've done very low force decouplers which seem to work okay as long as I decouple high enough in the atmosphere that they're not pressed into my heat shield for most of the aerobrake.

Thanks!

[Kobymaru]

5 hours ago, brymck said:

any way to correct for deviations caused by decoupling?

Most of my atmospheric landings in the latest version have required that I dump the engine/tank portion of, say, a Munar lander in favor of something more like a heat shield-y facing surface retrograde to have a less explosion filled landing experience. So, I get a good idea of where the entire craft would land, but then after decoupling it shifts drastically to the west. Basically I try to make my landing well to the east of KSC and the ejection force from the decoupling knocks the landing spot back west toward KSC, but it would be great to be as exact as possible with the process.

I've done very low force decouplers which seem to work okay as long as I decouple high enough in the atmosphere that they're not pressed into my heat shield for most of the aerobrake.

Thanks!

It's not just about the decoupling force. The main issue in your case is that the craft has totally different aerodynamics after decoupling. If you ditch your heavy engine and only have a tiny light capsule, that is going to cause a lot more drag.

And there is really not a whole lot you can do to fix that. You could guesstimate how much it drifts after decoupling. The most precise way is to leave some RCS thrusters on the final capsule with which you can correct your trajectory.

[FrontLineFodder]

Kobymaru,

should I use the latest version (1.6.7) on the current KSP 1.2.2 ?

[Kobymaru]

23 minutes ago, FrontLineFodder said:

Kobymaru,

should I use the latest version (1.6.7) on the current KSP 1.2.2 ?

I don't know. It's compiled for 1.2.9, but maybe it works for 1.2.2. Just try!