CaptKordite Posted July 5, 2016 Share Posted July 5, 2016 I just flew a mission to Minmus. In orbit around Kerbin I was fine. Rock steady. In transit, I was fine. No change at all in periapsis or apoapsis. In a 10km orbit of Minmus my periapsis was loosing nearly 30 meters per second. So, even if the relative velocities between two craft were not that much, the fact that both of them are falling towards the surface at 30 m/s really kind of interferes with docking. Link to comment Share on other sites More sharing options...
p1t1o Posted July 5, 2016 Author Share Posted July 5, 2016 On 7/2/2016 at 11:50 PM, NathanKell said: unavoidable limitations in using the integration method PhysX uses, and the floats PhysX uses. You make it sound incurable, is there a fix on the horizon, however far away that may be? Apologies if that is a silly question. Link to comment Share on other sites More sharing options...
problemecium Posted July 5, 2016 Share Posted July 5, 2016 I like it the way it is. Much better to needlessly have an option to turn something off than to turn something on and have half of us want to turn it off and not be able. Surely everyone in here has been to a popular website or used a popular app or OS and raged when the devs took away the option to turn something off... Link to comment Share on other sites More sharing options...
CaptKordite Posted July 6, 2016 Share Posted July 6, 2016 Turn what on or off? I'm not seeing an option. I see my space station falling from Minmus orbit any time I look at it. I see something that had been working no longer working. Link to comment Share on other sites More sharing options...
Superfluous J Posted July 6, 2016 Share Posted July 6, 2016 1 hour ago, CaptKordite said: Turn what on or off? I'm not seeing an option. I see my space station falling from Minmus orbit any time I look at it. I see something that had been working no longer working. There is a toggle in the global options screen. It's a checkbox. I don't remember the exact wording but it's there. Far right side of one of the many screens. Whether or not that works, and assuming your save is vanilla (or you can recreate the problem in vanilla) I bet NathanKell would love a copy of your save. Link to comment Share on other sites More sharing options...
CaptKordite Posted July 7, 2016 Share Posted July 7, 2016 Orbital Drift Compensation was on. I turned it off and it had no affect on the drifting orbits. I went back to the settings and it was back on again so I cannot be sure if it was ever off. Link to comment Share on other sites More sharing options...
p1t1o Posted July 7, 2016 Author Share Posted July 7, 2016 (edited) 8 hours ago, CaptKordite said: Orbital Drift Compensation was on. I turned it off and it had no affect on the drifting orbits. I went back to the settings and it was back on again so I cannot be sure if it was ever off. If the compensation calculations result in a worse performance than without it (apparently this can happen due to the nature of the problem) it will disable itself, meaning there will be no difference if it is on or off. Something about the situations you were/are in puts your orbit in that category I guess. On another note, has anyone heard anything about/have any idea about, the answer to this question?: On 7/5/2016 at 9:36 AM, p1t1o said: On 7/2/2016 at 11:50 PM, NathanKell said: unavoidable limitations in using the integration method PhysX uses, and the floats PhysX uses. You make it sound incurable, is there a fix on the horizon, however far away that may be? Apologies if that is a silly question. Edited July 7, 2016 by p1t1o Link to comment Share on other sites More sharing options...
shanaman Posted July 10, 2016 Share Posted July 10, 2016 I'm not sure if this will be of any help, but I made a couple videos that hopefully demonstrate the issues I have with docking around the mun. In the videos I am always having to fight against the phantom forces which makes docking a lot harder. Also over the course of docking, un-docking, and re-docking my periapsis drops by 5000 meters. This was a clean install with only Kerbal Engineer Redux and Docking Port Alignment Indicator mods installed. I used two of the stock ships (Super Heavy Lander) put into orbit around the mun. I have re-created this in vanilla KSP but don't have any video currently. This video I just undock, no SAS. http://plays.tv/video/5781f3112e85cb1ca0/ksp-1-1-3-phantom-forces-or-orbital-drift- This one I fight against the forces and manage to dock again. http://plays.tv/video/5781f414e6f22ff95d/ksp-1-1-3-docking-with-phantom-forces Lastly once re-docked and SAS is turned off, the ship undergoes some strange rotational acceleration. http://plays.tv/video/5781f47eee049ae755/more-phantom-forces I have been playing since version 0.18 and according to Steam I have played over 1000 hours. To me there is a definite problem here that wasn't always present, but maybe my problem is different from this one and has another cause. I'm open to any suggestions for a fix that anyone has. More or less posting this just to see if this is what others are seeing. Thanks Link to comment Share on other sites More sharing options...
Tyko Posted July 10, 2016 Share Posted July 10, 2016 (edited) I just tested and confirmed that if my station is above 100Km from Minmus its orbit stays rock solid. My workaround will simply be to test each planet/moon for the point at which the orbit is stable (maybe it's 100K for all of them) and then always place my stations above that altitude. Edited July 10, 2016 by tjt Link to comment Share on other sites More sharing options...
CaptKordite Posted July 10, 2016 Share Posted July 10, 2016 I, too, had noticed an altitude factor. My space station and another craft I put into low Mun orbit (20 something just under 60km respectively) had the issue but a ScanSat at 250km was rock solid. I hadn't had a chance to try different orbits to see just where that line is but it wouldn't surprise me if it was the same 100km. Link to comment Share on other sites More sharing options...
CaptKordite Posted July 11, 2016 Share Posted July 11, 2016 So, now I have tested it and, like Minmus, a Mun orbit below 100km has the drift issue while an orbit above 100km is stable. Actually, it depends on where the craft is. If you have an orbit that's, for example, 110km by 70km, when the craft is above 100km the orbit is steady and when it drops below 100km the drift issue appears. Link to comment Share on other sites More sharing options...
Tyko Posted July 11, 2016 Share Posted July 11, 2016 It definitely seems like 100km is the magic number - at least for Kerbin and its moons. Since circular orbits make rendezvous so much easier I'm just going to stick with placing my stations in at least 100x100km orbits Link to comment Share on other sites More sharing options...
Corona688 Posted July 11, 2016 Share Posted July 11, 2016 (edited) I'm a sloppy enough pilot that if I encountered this bug I'd never know it. That it doesn't hurt things on rails, that my stations aren't going to burn up when I'm not watching them, makes me quite happy. Edited July 11, 2016 by Corona688 Link to comment Share on other sites More sharing options...
Kerbart Posted July 11, 2016 Share Posted July 11, 2016 Is this the same issue where, when you timewarp with ships inside the physics bubble, the other ship all of a sudden jumps 50m or more? I always think of it "sideways" but now that I'm reading this threat I suspect that it's actually a jump in altitude (due to the way the view is oriented it looks sideways). I can't put my finger on it but it seems to happen when the target vessel (or station) is in the 1000-200m range. Perhaps it happens at a greater distance but I wouldn't notice, and I don't see it happening at closer range (thank goodness). Link to comment Share on other sites More sharing options...
Tyko Posted July 11, 2016 Share Posted July 11, 2016 1 hour ago, Kerbart said: Is this the same issue where, when you timewarp with ships inside the physics bubble, the other ship all of a sudden jumps 50m or more? I always think of it "sideways" but now that I'm reading this threat I suspect that it's actually a jump in altitude (due to the way the view is oriented it looks sideways). This is talking about "jittery" orbits where AP / PE will change by a few meters very rapidly when the vessel is active. When the vessel is on rails in time warp it doesn't happen Link to comment Share on other sites More sharing options...
p1t1o Posted July 12, 2016 Author Share Posted July 12, 2016 (edited) 15 hours ago, tjt said: It definitely seems like 100km is the magic number - at least for Kerbin and its moons. Since circular orbits make rendezvous so much easier I'm just going to stick with placing my stations in at least 100x100km orbits It makes me happy too, that my game doesn't self-destruct if left to its own devices. Im also happy that my computer doesn't catch fire if I leave the bedroom door open and that my curtains aren't made of spiders. I'm glad that progress is being made, but being out of the game for the moment, I don't really see myself getting back into KSP without 100% stable orbits, I don't think that that is unreasonable in a space game/simulation. Perhaps this problem was present before, but less detectable due to other problems. But now it *is* (and with the current fix, still is) detectable and its an issue. I asked a couple of times if the nature of the problem means that a 100% fix is impossible. Does anyone know if that is true/false? Edited July 12, 2016 by p1t1o Link to comment Share on other sites More sharing options...
CaptKordite Posted July 13, 2016 Share Posted July 13, 2016 I'm not sure I believe that a 100% fix isn't possible because when 1.1.3 came out, all my orbits, whatever the altitude, were stable. I tested them because the same thing had happened with 1.1.2. Things were fine for a time and then they weren't Link to comment Share on other sites More sharing options...
CaptKordite Posted August 28, 2016 Share Posted August 28, 2016 My career has finally gotten me interplanetary and I have probes at Duna. In orbit around Duna itself, the orbit is stable at all altitudes. However, around Ike, the orbit is unstable below 100km, just as around the Mun and Minmus. So, the bug apparently affects moons but not planets. Link to comment Share on other sites More sharing options...
Tyko Posted August 30, 2016 Share Posted August 30, 2016 (edited) On 8/28/2016 at 5:44 AM, CaptKordite said: My career has finally gotten me interplanetary and I have probes at Duna. In orbit around Duna itself, the orbit is stable at all altitudes. However, around Ike, the orbit is unstable below 100km, just as around the Mun and Minmus. So, the bug apparently affects moons but not planets. Thanks for confirming. I'm actually on my way to Duna now and you just saved me some trial and error.. That said, I've kind of settled on 150K orbits for motherships/bases where docking maneuvers are common. It offers plenty of room for low / fast orbits and keeping it consistent means it's a lot easier to remember Edited August 30, 2016 by tjt Link to comment Share on other sites More sharing options...
CaptKordite Posted September 7, 2016 Share Posted September 7, 2016 http://kerbaldevteam.tumblr.com/post/150051628694/devnote-tuesday-12-is-getting-ever-closer Don't see anything about this particular issue. Link to comment Share on other sites More sharing options...
Sneaky Bstard Sword Posted September 7, 2016 Share Posted September 7, 2016 On 7/2/2016 at 6:50 PM, NathanKell said: No, no one said anything about 100km orbits in this regard. What I have said is that when the drift compensation would make things worse rather than better, it automatically disables. Because, and let me repeat this one more time, there are basic, unavoidable limitations in using the integration method PhysX uses, and the floats PhysX uses. We have band-aided it as much as we can, but I dare say if you have survived three years of KSP where this issue was worse, you can survive it when it's better. Since when the drift compensation is off, the application of the force of gravity is exactly the same as it always was. If the limitations are with PhysX's math calculations, why don't you use a better integration/float system (say, from a non-PhysX library) and have the rest of the PhysX calculations be done with the value from the separate library? I don't know anything really about the PhysX backend, but it seems like something you could do. Then again, if that was possible, I guess it would probably already have been implemented. Link to comment Share on other sites More sharing options...
John FX Posted September 7, 2016 Share Posted September 7, 2016 On 27/06/2016 at 8:48 AM, p1t1o said: @NathanKell Thanks for weighing in (and for tackling thankless bugs!) its immeasurably more reassuring to hear things "from the horses mouth". It sounds like the orbital bug is a right JohnSnow Hehe, you mean it knows nothing? Link to comment Share on other sites More sharing options...
p1t1o Posted September 8, 2016 Author Share Posted September 8, 2016 14 hours ago, John FX said: Hehe, you mean it knows nothing? I was going for "stand-up guy" but either way Link to comment Share on other sites More sharing options...
M4ssler Posted September 15, 2016 Share Posted September 15, 2016 (edited) Hello, before a few days i start a new game, i fly to the mun and my orbit was decay. Then I reinstall and try it stock and the orbit bug around mun was there again. Sure its a game, but i´m a little sad that i have to stop playing ksp because it actualy unplayable. To start a new career with 1.2 is no option, because i spend many hours and have a lot of ships with around 120 mods Is there any known way to fix it now? I´m playing 1.1.3 edit: My satellite at 1200km orbit was stable, other one at 240km was stable too. If my vseel is over 100km it is not moving. under 100km i have decay. The same i read a few posts higher. Edited September 15, 2016 by M4ssler Link to comment Share on other sites More sharing options...
p1t1o Posted September 15, 2016 Author Share Posted September 15, 2016 @M4ssler Yes, it is still unclear as to whether or not this will be fixed 100%, or even if it *can* be fixed 100% in the current build. Any staff care to weigh in? Is there hope for the orbit bug? What is it like in 1.2? Link to comment Share on other sites More sharing options...
Recommended Posts