Youen

[old thread] Trajectories : atmospheric predictions

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It's not fuel lines or struts. My current craft doesn't have any of those and it's still exceptioning.

If I had to guess, I would say it's the hitchiker maybe? That's the only part on this vessel that isn't on the others (which worked fine)

My log:
[url]https://www.dropbox.com/s/ivrtklna104p7ty/output_log.txt?dl=0[/url]

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[quote name='rdwulfe']Youen, thank you so much for your continued work.[/QUOTE]

I second this. Thank you Youen for keeping this mod on your mind. I try and stay as stock as possible and AT is one of only 4 mods I use; it has been so helpful to me. After playing 1k+ hours into the game without it, I don't know how I managed without it.

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Looking forward to seeing this working again... I've never been great at targeted atmospheric entries and in the past, this always went a long way to making up for my deficiencies.

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Also really hoping this mod makes a comeback.  My best memories, proudest moments, and favorite projects in KSP pretty much all revolve around activities that are essentially impossible without it.

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The only problem I'm having with it is it's based on the current ship, not how the ship will be when you do a de-orbit burn and do another staging. It needs a way to run based on the craft after it has staged one more time.

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1 hour ago, Vorg said:

The only problem I'm having with it is it's based on the current ship, not how the ship will be when you do a de-orbit burn and do another staging. It needs a way to run based on the craft after it has staged one more time.

I think that would be really hard to implement. You would need to copy the whole vessel part tree (not sure if that's even possible), locate the staging events, do a "simulated staging".

And then, which "staged off" vessels would you actually use for calculation? There are often situations, where you stage and you have the "wrong" ship focussed. How would the simulation know?

This sounds like a tremendous amount of work, for a feature. Personally, I'd rather Youen doesn't burn out and makes constant updates to this mod.

 

Feel free to clone the repository, and start hacking on that, though!

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Keep getting the following exception for my spaceplane:


 

Spoiler

 

NullReferenceException: Object reference not set to an instance of an object
  at DragCubeList.AddSurfaceDragDirection (Vector3 direction, Single machNumber) [0x00000] in <filename unknown>:0

  at Trajectories.StockAeroUtil.SimAeroForce (.Vessel _vessel, Vector3 v_wrld_vel, Double altitude, Double latitude) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.computeForces_StockAero (Double altitude, Vector3d airVelocity, Vector3d vup, Double angleOfAttack, Double dt) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.computeCacheEntry (Int32 v, Int32 a, Int32 m) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getCachedFARForce (Int32 v, Int32 a, Int32 m) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.sample2d (Int32 vFloor, Single vFrac, Int32 aFloor, Single aFrac, Int32 mFloor) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.sample3d (Int32 vFloor, Single vFrac, Int32 aFloor, Single aFrac, Int32 mFloor, Single mFrac) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getCachedForce (Double velocity, Double altitudeAboveSea, Double angleOfAttack) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getForces_StockAero (.CelestialBody body, Vector3d bodySpacePosition, Vector3d airVelocity, Double angleOfAttack, Double dt) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getForces (.CelestialBody body, Vector3d bodySpacePosition, Vector3d airVelocity, Double angleOfAttack, Double dt) [0x00000] in <filename unknown>:0

  at Trajectories.Trajectory+<AddPatch>d__50.MoveNext () [0x00000] in <filename unknown>:0

  at Trajectories.Trajectory+<computeTrajectoryIncrement>d__45.MoveNext () [0x00000] in <filename unknown>:0

  at Trajectories.Trajectory.ComputeTrajectory (.Vessel vessel, Trajectories.DescentProfile profile, Boolean incremental) [0x00000] in <filename unknown>:0

 

 

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4 hours ago, CompB said:

Keep getting the following exception for my spaceplane:

  Reveal hidden contents

 

NullReferenceException: Object reference not set to an instance of an object
  at DragCubeList.AddSurfaceDragDirection (Vector3 direction, Single machNumber) [0x00000] in <filename unknown>:0

  at Trajectories.StockAeroUtil.SimAeroForce (.Vessel _vessel, Vector3 v_wrld_vel, Double altitude, Double latitude) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.computeForces_StockAero (Double altitude, Vector3d airVelocity, Vector3d vup, Double angleOfAttack, Double dt) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.computeCacheEntry (Int32 v, Int32 a, Int32 m) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getCachedFARForce (Int32 v, Int32 a, Int32 m) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.sample2d (Int32 vFloor, Single vFrac, Int32 aFloor, Single aFrac, Int32 mFloor) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.sample3d (Int32 vFloor, Single vFrac, Int32 aFloor, Single aFrac, Int32 mFloor, Single mFrac) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getCachedForce (Double velocity, Double altitudeAboveSea, Double angleOfAttack) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getForces_StockAero (.CelestialBody body, Vector3d bodySpacePosition, Vector3d airVelocity, Double angleOfAttack, Double dt) [0x00000] in <filename unknown>:0

  at Trajectories.VesselAerodynamicModel.getForces (.CelestialBody body, Vector3d bodySpacePosition, Vector3d airVelocity, Double angleOfAttack, Double dt) [0x00000] in <filename unknown>:0

  at Trajectories.Trajectory+<AddPatch>d__50.MoveNext () [0x00000] in <filename unknown>:0

  at Trajectories.Trajectory+<computeTrajectoryIncrement>d__45.MoveNext () [0x00000] in <filename unknown>:0

  at Trajectories.Trajectory.ComputeTrajectory (.Vessel vessel, Trajectories.DescentProfile profile, Boolean incremental) [0x00000] in <filename unknown>:0

 

 

Yes, this is a known bug since 1.0.5 dropped. Unfortunately, all the devs that could fix it don't have time at the moment. Please be patient.

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Good news, I've found how to properly handle fuel lines and struts (actually, all parts that have DragCubes.None set to true). So this bug is fixed.

Before submiting a new release, I'll make some more tests to check if there are other issues with other parts.

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9 minutes ago, Youen said:

Good news, I've found how to properly handle fuel lines and struts (actually, all parts that have DragCubes.None set to true). So this bug is fixed.

Before submiting a new release, I'll make some more tests to check if there are other issues with other parts.

@Youen Thank you

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It appears Trajectories doesn't work with FAR anymore (I get exceptions, and no trajectory is displayed), but that's weird because I'm pretty sure I saw it work on 1.0.5 a few weeks ago. Does anyone have the same issue? I've tested with FAR v0.15.5.4_Hoerner and v0.15.5.2_Helmbold.

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@Youen I have a question on the implementation this uses. I'm currently taking a Physics Simulations course, in which I am learning to simulate things in python, and for our final project we need to do something using RK4. Being the KSP nerd that I am, I chose to do an orbital simulation of a ship going from Kerb- sorry- Earth orbit to solar orbit and finally to an orbit about a binary star system, which would be chaotic (another requirement for the project). Do you use RK4 to do the predictions in this? If so, any tips for me?

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@Youen I'm currently using Hoerner, and as far as I can tell Trajectories is working properly. 

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OK, there was a problem with my installation of FAR (I think that's because I had two versions of module manager)

Anyway, when FAR is correctly installed, I can observe that the prediction works, but there is indeed the bug of vessels breaking due to aerodynamic stresses that happen during the trajectory prediction. An old bug that ferram fixed some time ago, but it seems recent changes have made it happen again. I'll double check in the FAR source code, and notify ferram if needed. There is also an issue with the cache update, I found a case in my tests where predictions were wrong, and manually forcing the cache update fixed it, but normally that update button should not be needed (the system is supposed to detect when the ship has changed, for example after staging, and reset cached data automatically). So the current version is not ready to work with FAR, there is still some work.

In the meantime, I've posted a new release that should work fine with stock aerodynamics, let me know if it doesn't.

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The new version Worked fine to me, no more exception problems

Thanks a lot for your work

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A question for Youen or anyone who knows the answer:

The updated trajectories uses a new moduleManager.2.6.13.dll (the old one being moduleManager.2.6.3.dll). DockingPortAlignment-6.2 uses the old one (moduleManager.2.6.3.dll). So for now I have BOTH  moduleManager.2.6.3.dll and moduleManager.2.6.3.dll being loaded. I just want to make sure that will be ok.

 

Thank you in advance

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38 minutes ago, someuser said:

A question for Youen or anyone who knows the answer:

The updated trajectories uses a new moduleManager.2.6.13.dll (the old one being moduleManager.2.6.3.dll). DockingPortAlignment-6.2 uses the old one (moduleManager.2.6.3.dll). So for now I have BOTH  moduleManager.2.6.3.dll and moduleManager.2.6.3.dll being loaded. I just want to make sure that will be ok.

 

Thank you in advance

As a general rule, it's never okay to run (2) copies of ModuleManager.  Just use the 2.6.13 version and remove anything older.

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@WuphonsReach: Strictly speaking, that's not correct. Module Manager disables older versions of itself. So while you can safely delete the older one, you can also ignore it.

Reference:  http://forum.kerbalspaceprogram.com/index.php?/topic/50533-105-module-manager-2613-november-9th-with-more-sha-and-less-bug-upgrade/#comment-720814

Edited by eightiesboi
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Just started using this, its taking some getting used to but I can see this is going to be great for me. Thanks for your hard work.

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