Staged Parts Remain Attached - A New/Different Twist Including Messed Up Camera Plus More

[LameLefty]

First off, this is NOT bug we all discovered on the first day when entire stages failed to properly separate unless you put the decoupler into its own stage ... this is something new and different (to me).

So, setup: I built a very large LH2 powered nuclear transfer stage with a methalox lander on top for mission to Laythe. That whole stack is sitting on top of a large methalox core booster with four large SRB strap-on boosters. For pitch control on ascent, I have four large stabilizers attached to that core stage.  Climbing to LKO was utterly perfect except for the fact that the core stage was managing to pull propellants through multiple decouplers and in-line docking ports (and a giant LH2 tank in between) even with Fuel Crossfeed disabled - yes, I know - another known bug. 

Anyway, after getting to a roughly circular 160km orbit around Kerbin, I staged away the booster, leaving the nuclear stage and lander alone and ready to make the burn to Jool.  For some odd reason, one of the large stabilizer fins attached to the core stage then separated from the core and remained relatively close to the transfer vehicle. After planning my Jool burn and timewarping to the burn time, the stabilizer was still there. During the burn, the core stage rapidly left the stabilizer behind but at the same time, my camera view began to drift, as if trying to remain focused on the combined center of mass of everything, including that wayward stabilizer fin. Worse, during the 3-1/2 minute burn, the vehicle seemed to lose its ability to point or maintain control, almost like that now far away fin was somehow dragging or impeding the transfer burn like an anchor.

After finally completing some semblance of the burn, I was very far off my intended trajectory. I decided to try to correct it once outside Kerbin's SOI. Once outside the SOI, I flipped from Map to flight view and my vessel is absolutely no where to be found. It's there on the map and I have controls for it, but the camera doesn't see it and cycling through came views does not bring it back into focus. Again, it's like the camera view has become anchored to some hypothetical center of mass between that weird aberrant stabilizer fin and my actual craft. I tried deleting all the debris in my save from the Tracking Station but this fin doesn't show up. 

I've reloaded the save, reloaded earlier quicksaves, etc. but every time I stage away the core booster, that one fin ends up detached from the core and remains in the vicinity of the transfer stage, and it causes the same issue even if I quit and reload the game. I've  also tried parsing the .json of the save file to see if I can delete the weird part, but file for the vessels is looooong and difficult to parse on first impression.

My next effort will be to try to transfer the craft file to a brand new clean save and see if that fixes the issue.

[whatsEJstandfor]

This is pretty common; seems to happen with wing pieces and landing legs. The cause seems to be that, when the craft is saved, those pieces lose track of which part they were parented to. This causes them to still be treated as a part of the vehicle, but not attached to anything. Since they're still a part of the vehicle, the "center of mass" as it were tends to drift as the main vehicle and the broken part separate, and the camera tries to follow that center.

The only fix I've seen (and one I've successfully done a few times) is by doing surgery on the save file to either reparent the broken part to its original parent, or to delete the part entirely. For me, I did the latter, because it happened to some wings, and those were no longer needed since I was in orbit.

The actual process is pretty tricky to explain here but, if you open your save file (after making a backup, of course!), you should be able to identify the broken part by searching for this string verbatim:

"attachedPartNodeID": ""

Here's an example of one of my busted parts:

It will also show a GUID of all zeroes for the "AttachedPartGuid" tag. Scroll up a bit to where the part starts. You'll see "partName" followed by the part's name (presumably yours will include the word "stabilizer")

Above that, you'll see a line that says "partGuid", and then an open curly brace right above that. Select that curly brace and find its corresponding closed curly brace a few hundred or thousand lines down, and delete that whole block. This is how you can delete the busted part. Save the file, and open it in-game; the part should now be gone.

Hopefully, with the new patch, this won't be an issue anymore; doing this kind of manual save-fixing isn't tenable.

[Jason_25]

I worked around this problem by changing the root part to the cockpit of the carrier vehicle.  Previously it was a fueselage part of the carrier vehicle.  

edit:

I consider this bug the "drifting camera bug", "wrong vehicle control bug", and "vehicle (reported) destroyed upon undocking bug".  Also I am now seeing a bug related to this that causes the frame rate to go from around 25 to less than 1 when the bugged undocked vehicles remain near each other.

Also the workaround above is not 100% effective.  Another way to trigger this is to bump the vehicles together after undocking.  If I hurry the vehicles away from each other this bug does not trigger.

Edited March 13, 2023 by Jason_25