[old thread] Trajectories : atmospheric predictions

[mcirish3]

Squad says running KSP 64-bit on Windows is experimental and has more issues under 0.25 than it did under 0.24. There are a large number of bugs in Unity 64-bit and KSP 64-bit on Windows. Because of all the crap mod builders received about bugs beyond there control under KSP 0.24, many have decided to have their mods disable themselves under KSP 64-bit on Windows and say so.

Ya I totally get it. I am not mad any any one, just bummed out. I know everyone thinks the only reason for running x64 is to increase RAM availability but if you have a 5-8 year old pc there are other advantages especially if the processor is an AMD.

[Youen]

OK, I've added a note about that in the first post, but I wonder if you wouldn't be better off playing the 32 bits version, or maybe installing a dual boot linux (I've heard the linux version runs very well performance wise, but haven't tried myself). So far, I've heard only bad things about KSP 64 on Windows.

[mcirish3]

THe Linux solution may be reasonable but really don't see a need since stock win64 runs nearly perfectly on my PC. The only trouble is everyone else seems to have trouble with it. Which is unfortunate since really it is kinda like the English system VS. Metric System. Stupid American engineers refuse to switch to the Metric system because they don't want to learn something new. Similarly Computer programmers don't want to switch to x64 because they don't want to learn something new. I see no reason 32 bit support could not be built in as a legacy system with everything being designed from the ground up to be x64.

Sorry about the rant.

[Starwaster]

Stupid American engineers refuse to switch to the Metric system because they don't want to learn something new.

Sorry about the rant.

That's a pretty naive thing to say. It has nothing to do with engineers wanting or not wanting to switch to metric. Lots of them can use metric just fine but they don't live in a vacuum. They need to deal with lots of other people who don't know metric. The reasons for not going metric are much broader than such a narrow subset of people.

[Jacke]

THe Linux solution may be reasonable but really don't see a need since stock win64 runs nearly perfectly on my PC. The only trouble is everyone else seems to have trouble with it. Which is unfortunate since really it is kinda like the English system VS. Metric System. Stupid American engineers refuse to switch to the Metric system because they don't want to learn something new. Similarly Computer programmers don't want to switch to x64 because they don't want to learn something new. I see no reason 32 bit support could not be built in as a legacy system with everything being designed from the ground up to be x64.

Sorry about the rant.

Don't rant. Understand first.

Aircraft and ships uses altitude in feet and ranges in nautical miles because that's the international convention that all nations, pilots, and traffic control work on. It will be the last use of non-metric units because it will be the hardest to change without mishap. Like what happened in World War 2 in the Pacific theatre when the United States Navy used nautical miles and the United States Army Air Force used statute miles. And U.S.A.A.F. aircraft were sent on a mission given data in nautical miles and compared that to their aircraft loaded radius of action in statute miles and thought it would work and it didn't and air crews died. Which lead to all air forces and then civilian pilots standardizing on nautical miles. Altitude in feet got included.

All operating systems now can run in 64-bit mode. But a lot of the software is still 32-bit. Which is why all 64-bit operating systems have robust ways of running 32-bit code. I'm typing this post into the latest Firefox. Firefox on Windows is still 32-bit code, even though the OS is 64-bit, because that's the compiled versions supplied by Mozilla. Under Linux, Firefox can be 64-bit. And then I have other hoops to jump through because other stuff that runs in the browser is still 32-bit.

My OS right now is Windows 8.1 64-bit. But I run the KSP 32-bit executable because under Windows Unity 64-bit and KSP 64-bit are full of bugs. Game-breaking bugs. Squad called Windows KSP 64-bit experimental and says it got worse in KSP 0.25.

Just because you've run Windows KSP 64-bit without issue for a while doesn't change that. And doesn't change the fact that you will likely hit one of those bugs. And you add in the number of players who play any mod and they will have issues with KSP 64-bit. Which they demand the mod writer fix. Even though it's impossible. Because they don't know and don't care to figure out.

And thus a lot of mod writers are sick of this crap and now have their mods refuse to run under Windows KSP 64-bit. Because it's experimental. That won't change until Windows KSP 64-bit improves.

Edited October 18, 2014 by Jacke

[cy-one]

I hope I don't get flak for not reading 36 pages

Quick question:

This is already useful as it is (making landings on atmospheric and nonatmospheric bodies A LOT easier), but does it also work with aerobraking?

One thing I'm kinda desperate to find is a mod that shows me how an aerobrake will change the trajectory. You mentioned that the node system is kinda tricky there, because one would have to edit a node that's somewhere else.

I personally wouldn't care about that, just a visual representation of how the trajectory would look after aerobraking would make so much stuff so much easier

[Starman4308]

I hope I don't get flak for not reading 36 pages

Quick question:

This is already useful as it is (making landings on atmospheric and nonatmospheric bodies A LOT easier), but does it also work with aerobraking?

One thing I'm kinda desperate to find is a mod that shows me how an aerobrake will change the trajectory. You mentioned that the node system is kinda tricky there, because one would have to edit a node that's somewhere else.

I personally wouldn't care about that, just a visual representation of how the trajectory would look after aerobraking would make so much stuff so much easier

Yes.

And apparently the forums don't like laconic, <10 character replies.

[cy-one]

Gods, that's a relief to hear. I waited so long for a mod that does that

Thanks Youen!

(and Starman for the answer :3)

[Starwaster]

And apparently the forums don't like laconic, <10 character replies.

Nope. (ten characters)

[Gfurst]

Just adding my ten cents to the previous discussion.

Linux is awesome, and KSP 64 runs perfectly fine on it, and actually runs better without active texture management (just found this out), and of course, I also have moderately powerful PC.

The imperial system is kinda silly (come on, not trying to be offensive), and ery few countries use it, however, two of those countries are very powerful world potencies, and as such a lot of other countries also need to use to standard even though the official standard for the country is the metric system.

Nautical miles however makes sense, they're based on the arc of the equator, "approximately one minute of arc measured along any meridian", so its easier to read on charts.

For anything else the metrical system is quite better and easier to calculate with, meters, Newtons, grams....

Cheers!

[Jacke]

Nope. (ten characters)

[Retsof]

Well, this has become one of my must have mods. Quick question though. Would it be possible to specify it to predict for a certain stage? Because I like not having to get out and push my pod to fine-tune those landings.

[Youen]

You mentioned that the node system is kinda tricky there, because one would have to edit a node that's somewhere else.

I thought about that some time ago, but the actual implementation is that you use the manuever nodes as usual, but you can't place any after the aerobraking. So you will see the trajectory after aerobraking, but you can't use it to plan further maneuvers. Also it won't compute SoI changes. Maybe some day I'll find a way to trick KSP by adding conics that it didn't compute itself, but the API does not look like it's made for that, so I don't know if that will be possible or not.

Of course, you still see the stock trajectories after aerobraking, that do not take into account the atmosphere entry, and you can place maneuver nodes on them (that are ignored by the mod), but they are useless as you'll never get there.

Would it be possible to specify it to predict for a certain stage?

That's already a feature request, but at this time you can't.

Edited October 24, 2014 by Youen

[Retsof]

That's already a feature request, but at this time you can't.

Ah, thanks for answering.

[S1gmoid]

Um... All trajectories I get are off by more than 90 degrees of longitude. Is this because most ballistic re-entry vehicles point retrograde due to aerodynamic forces, and Trajectories defaults to prograde?

[dlrk]

How does this work with 6.4x Kerbin on Lin64?

[Starman4308]

Um... All trajectories I get are off by more than 90 degrees of longitude. Is this because most ballistic re-entry vehicles point retrograde due to aerodynamic forces, and Trajectories defaults to prograde?

You have to open up the Trajectories window in map view and play with reentry profile: by default, it calculates it with your craft pointing straight prograde all the way through.

[Youen]

How does this work with 6.4x Kerbin on Lin64?

I don't know 6.4x Kerbin, but it looks like it's a config for RSS, which has been reported not to work with Trajectories (haven't tested it myself)

I haven't got any negative report concerning linux 64bits. It should work, but I haven't tested it either.

[Starman4308]

I don't know 6.4x Kerbin, but it looks like it's a config for RSS, which has been reported not to work with Trajectories (haven't tested it myself)

I haven't got any negative report concerning linux 64bits. It should work, but I haven't tested it either.

Well, I can report that, among 37 other candidate mods, Trajectories might be responsible for exploding rockets on my very recent Linux 64-bit installation.

Useful feedback to follow if I narrow it down to Trajectories (unlikely).

[Hyomoto]

Against my better judgement I gave this a try and it's been working okay until now. After a very routine takeoff, I brought my apoapsis down to reenter Kerbin's atmosphere and KSP started lagging badly. I got some message like 'too many trajectories' or something like that. KSP normally runs at a sharp 60 fps all the time, so for one mod to be able to bring it to a crawl is just something I'm not going to bother with right now. I wish I had better information for you, but the message it gave isn't in the log and if I'm correct, after I exited and re-entered the flight scene it has just simply disabled itself anyways.

However, I don't know for sure but that might mean the simulation runs despite having 'display trajectories' unchecked, since that didn't alleviate the lag.

Edited October 20, 2014 by Hyomoto

[Youen]

This message is normal, it just means that since the atmospheric trajectory is too long (very shallow), the prediction stops in mid-air to avoid simulating forever. The lag you are experiencing would more probably be caused by a bug, because if KSP runs smooth without the mod, it should still run well with, even for the maximum trajectory length. Nothing relevant in output_log.txt ? Most times such a bug happens, the lag is actually caused by exceptions logged every frame, so the corresponding part of the log is easy to spot by scrolling (lot of identical errors in a row). Don't know if it's what's happening to you, though. I assume you've tested with the latest version ? (0.4.1) And what version of KSP ? (0.25, 32bits, windows ?)

If you have the time, I would be interested by your .craft file (composed of stock parts preferably) and the log file.

[z26]

I'm using this with NEAR and 32 bits windows, so far managed to make a capsule reentry within 3km of ksc after a few quicksaves. However, I had to reenter the improper way (narrow end first) because I was confused on how orientation works. Somehow, +180 degrees and -180 degrees give different results, aren't those supposed to result in the same orientation?

It might be cool to have the option (rather than fiddling with sliders) to steer your spacecraft in the orientation you want to make your whole descent in, (relative to the horizon OR the prograde marker, depending on your preference) then push a button to compute the trajectory of that descent.

[Hyomoto]

Well, it was definitely a shallow reentry. The craft is stock except for Deadly Reentry, it uses the heat shields, but it's made entirely out of the first tier of parts. So parachute, pod, engine and tanks, nothing exciting. Latest version, 0.41 and KSP 32-bit. The log, however, didn't mention anything useful.

It is may be possible that Final Frontier doesn't like to play well with Trajectories. I did notice in the log it had a long list of entries around that time, but they came to an end so it's hard to say if it happened alongside the reentry or before. The only way I can think of to test it would be to send a Kerbal without any badges up and see if it happens again. The flight plan was very basic: take off, orbit, de-orbit. Not a lot of nuance to play with but maybe I can recreate it if I feel like testing it.

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.

Edited October 21, 2014 by Hyomoto

[Wolfwood]

Some command pods have ablative shielding integrated in them by default, that you can edit like any other resource. Ive got rid of it in VAB before launch. So no deadly reentry shielding is present on the craft. This is one of the crafts ive used in testing.

Edit: I usually do my reentries without SAS assist, but i suspected that the wobble might expose something to the airstream that will couse additional drag, so for this particular test ive left it on. I forgot to put that in screenshots, those small rtgs arent causing any drag.

http://imgur.com/a/fKjmy

Sorry about the size, im new to imgur thing, album was set to thumbnails only. Silly thing ate my navball. Im pointing retrograde all the way down

Im too tired tonight to try a clean install without DRE altogether, as some other dre mechanic might be at play here. And to be honest its just slight inconvinience. I understand that mod is in beta, and not yet DRE compatible. Pease treat my post not as a bug report, but as just an observation of wierd part behavior, that my ocd couldnt left alone That might or might not be of use to you in future development.

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*

[Gfurst]

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!