[old thread] Trajectories : atmospheric predictions

[ron1n1]

Has anyone here tried using Trajectories with TweakScale? I installed Trajectories a few days ago and zoomed back to a few ships with scaled parts. All of the parts were scaled back to their original model size (which made everything look like the Diadact's armour in Halo 4, free-floating).

When I went back to VAB, I noticed the Tweakscale option had completely disappeared. I isolated the problem when I removed the Trajectories mode.

Has anyone else noticed this problem? Sorry if someone already brought it up, but I googled searched it here and didn't see a post on it.

[Oafman]

I'm really enjoying this mod. I've been doing some aerobraking around Eve, and was impressed by how accurate the predictions were.

Merci Youen!

[Youen]

Has anyone here tried using Trajectories with TweakScale? I installed Trajectories a few days ago and zoomed back to a few ships with scaled parts. All of the parts were scaled back to their original model size (which made everything look like the Diadact's armour in Halo 4, free-floating).

When I went back to VAB, I noticed the Tweakscale option had completely disappeared. I isolated the problem when I removed the Trajectories mode.

Has anyone else noticed this problem? Sorry if someone already brought it up, but I googled searched it here and didn't see a post on it.

No one reported such issues yet, and in fact I doubt it's actually related to Trajectories. The mod mostly doesn't interact with anything, except FAR. Also, I play with tweak scale all the time and didn't have issues. Anything relevant in your log file? Also, you said the problem disappeared after removing Trajectories, but maybe it was just because you restarted the game? Let me know if you can reproduce the issue, as that would be a huge bug to fix (though apparently a rare one).

[Youen]

im still on the 24.2 version, and DRE i don't think is in play. I don't have DRE or FAR install and the same trajectory effect happens to me. I plot the landing, then separate the "service module" which then makes my landing spot fall short of where i aimed. Naturally i just assumed its taking into account its current mass, instead of the final stage mass *shrug*

Indeed, stage separation is not implemented yet. This looks like normal behavior in relation with the current features.

[Youen]

Hey there, thanks for this addon, its immensely useful.

A small suggestion though, move the toolbar icon to something like blizzy toolbar, that button that has to little functionality to be present all the time.

Plus for better functionality, you could use the left click button to toggle visualization of the trajectories, and the right click to bring up menu.

This way user can save a bit on performance whenever they feel they feel its not needed.

Hope you find this useful, cheers!

The altest version (0.4.1) should integrate with blizzy's toolbar instead of the stock one if blizzy's is installed. Let me know if it doesn't...

The left/right click has already been suggested.

[Youen]

Honestly, I hate dropping a bad bug report in your lap but this is why I was just going to wait. The mod looks good, I like where it's going and it's a great idea but I just really don't feel like troubleshooting a mod right now.

No problem. Thanks for reporting the issue anyway. I'll test with a similar ship if I find some time, but at the moment I can't think of anything that could go wrong with it.

I think I'll add a display of how much time is spent computing trajectories, and also add a visual indicator when an error occurs during computations (such as a counter), so that bug reports are more precise.

Edited October 24, 2014 by Youen

[TMS]

Hi there,

Is there a way to force the icon into the stock toolbar?

I have blizzy's toolbar installed for a couple of older mods that rely on it, but would prefer Trajectories to appear in the stock toolbar (cleans up the map mode screen).

The OP kinda indicates that the stock toolbar is only used in the absence of Blizzy's toolbar. Is that correct?

Oh, updated to the most recent release and I'm impressed with the accuracy in stock and the improvements with manoeuvre nodes.

[Youen]

At this time, you can't choose (either blizzy's toolbar is installed and the icon goes there, or it isn't installed and the icon goes in the stock toolbar).

I've added the suggestion to be able to choose in the feature requests

[ymir9]

This mod is a life saver and works very well.

One suggestion: the ability to select trajectory prediction for future stages, as every time I dump my service module the drag profile changes dramatically.

A really great mod, thanks for all your work.

[MarcusQ]

Hi, I don't know if I'm using this mod correctly. I set my orbit for an aerobrake to lower my apoapsis a bit. During the aerobrake, I found my apoapsis decreasing substantially, and it ended up way inside the atmosphere. So it turns out the prediction was completely wrong.

In another case, I set up a trajectory to land very close to KSC. As I got closer, my prediction was getting further and further from the target. There's really something wrong here, and it's probably the mods I have installed (it's quite a long list). The thing is, the only aero mod I have installed is FAR.

Both tests were done with near identical craft; just a probe body with a KW small fuel track and an lv909. I can give you the full mod list, but it probably wouldn't make a difference. Thanks.

[Starman4308]

Hi, I don't know if I'm using this mod correctly. I set my orbit for an aerobrake to lower my apoapsis a bit. During the aerobrake, I found my apoapsis decreasing substantially, and it ended up way inside the atmosphere. So it turns out the prediction was completely wrong.

In another case, I set up a trajectory to land very close to KSC. As I got closer, my prediction was getting further and further from the target. There's really something wrong here, and it's probably the mods I have installed (it's quite a long list). The thing is, the only aero mod I have installed is FAR.

Both tests were done with near identical craft; just a probe body with a KW small fuel track and an lv909. I can give you the full mod list, but it probably wouldn't make a difference. Thanks.

Did you try adjusting your reentry orientation in the Trajectories window? Trajectories defaults to assuming you reenter directly prograde, and since your trajectory strongly​ depends on orientation in FAR, it will give you very inaccurate results if you were reentering tail-first.

[MarcusQ]

Did you try adjusting your reentry orientation in the Trajectories window? Trajectories defaults to assuming you reenter directly prograde, and since your trajectory strongly​ depends on orientation in FAR, it will give you very inaccurate results if you were reentering tail-first.

I did, but only for the first slider, which was my mistake For some reason I disregarded the other sliders. When I set them all to 180 degrees it worked; dunno why I ignored them!

[Geschosskopf]

This mod is the greatest thing since canned beer. Very accurate predictions

Before:

ALMOST after (t was bang on by the time it left the atmosphere):

YAY! No more repetitive "simulations" of aerocapture passes (F5, set Pe, try it, not like it, F9, tweak Pe, F5, repeat). I LOVE THIS. A thousand thankyous!

[jfjohnny5]

This mod is amazing. Definitely added to my list of "must haves" right next to Engineer and Alarm Clock. Especially now that I've discovered you can use the inherent lift capabilities of the command capsules to adjust your trajectory during reentry - I FINALLY have all the feedback needed to make accurate landings. Awesome job!

[Kerbas_ad_astra]

I'm liking this mod, but when I choose to set my impact point as a target, the red and green crosses z-fight with each other. It's not a huge deal, but it's kind of distracting. I would rather have the "real" (red) X on top, since that's where I'll actually go and it will move around as I perform maneuvers.

Edit: Alternatively, the target marker could have a different shape from the "you will land here" marker -- a circle or + shape, maybe.

Also, I had an issue where I could not recover a landed vessel (or switch to KSC or another vessel). The error log indicated that PatchedConicRenderer is involved, and this is the only mod I can think of that would be involved in that (information here). Unfortunately, I haven't been able to make the error happen again, so I can't be sure that this mod is involved.

Edited November 5, 2014 by Kerbas_ad_astra

[Youen]

Actually, the issue has already been reported. Not prioritary, though.

[Youen]

The error log indicated that PatchedConicRenderer is involved

Hard to tell if this is related to this mod. I don't modify conic patches, and I render trajectories using my own code (procedural meshes), so there is no obvious link, but I can't say for sure. The vessel was actually in "landed" state ? I once had issues with physics not stable enough for the ship to be considered landed (don't remember if it was on land or sea), but maybe that's unrelated to your issue (also, this was before I started working on this mod, so it wasn't related to the mod in my case).

[Kerbas_ad_astra]

I'm pretty sure the vessel was in a landed state -- the altimeter would drop down, and I could click the recover and space center buttons, but nothing happened. When I went into the output log, I saw those error stacks where the program tried to go from "FLIGHT" to "SPACECENTER" but failed.

If this mod doesn't do anything with conic patches, then I guess it must be some stock bug (I can't think of any other mod I use that touches orbit stuff). Thanks.

[numerobis]

Oooh, nice. It shouldn't be too hard to stick in the stock aero model either, at computeForces().

[Jivaii]

So this is what was on Scott's video of Kerb-Side.

[Youen]

Apparently, yes, Trajectories can be seen at the end on the map view.

Good video by the way, now I want to install Kerbin Side :-)

[ymir9]

Would it be possible for future versions to automatically detect body rotation speeds and compensate accordingly? That seems to be what isn't working in RSS.

[Youen]

That's already the case :-)

In normal mode, the cross indicating impact takes body rotation in account. In "body-fixed" mode, the whole trajectory is relative to the body rotating frame.

[Supraluminal]

I've been having problems with inaccurate trajectory predictions. It's mostly a problem with long/shallow reentries; it pretty consistently overestimates the length of my flightpath (i.e. my craft lands well short of the initially-predicted impact site). This is with FAR, using MechJeb to keep my craft pointed dead-on to my surface velocity vector and without moving any of the Trajectory AoA sliders off of zero. Am I doing something wrong? Is this a bug? Just an unavoidable limitation of the mod?

Great mod overall, though! Even inaccurate predictions are better than none, and it's generally pretty good when my reentry is on the steep side.

[rdwulfe]

This is now one of my Must Have mods. It's wonderful. I used tweeks and weirdness with MechJeb before so I could somewhat predict a landing, but this does it simply and elegantly, just how I like.I'd much prefer to have a few small mods that do simple, straight forward things so I can customize how I work than one huge behemoth mod.