Inconsistent Docking Problems

[Caviar]

What I came to observe is that the Docking Ports (Any size, any make) never behave consistently. Docks sometimes, sometimes doesn't. I have also ensured that the parts have the correct orientation, is controlled from the port, the destination port is targeted and everything else (disabling RCS and SAS just before docking). Didn't work out. I then tried editing the save file from various VERIFIED sources, but all i found was that they were in perfect order. Nothing indicated that the ports had erroneously considered itself docked when it wasn't. So drew a blank there too. I simply can't figure out the pattern of successful or unsuccessful docking.

Looks like the ports have a mood of their own. What am I missing?? The game runs smooth as butter, but a huge headache when i have to start docking stuff. If it doesn't dock, start the mission all over again and HOPE to work perfectly. I have come to notice that docking had issues in previous versions, say before year 2015. Very rarely have docking problems been reported in 2016-17, so I assume it's been debugged. So what would be my issue?

(I would have attached my quicksave.sfs file, but u cant figure out how.)

[Snark]

Hello, and welcome to the forums! 

I note that you've posted this in the sub-forum for modded installs.  The first thing I'd suggest checking is whether one of your installed mods may be causing the problem.  Try running a plain-vanilla stock copy of KSP that has no mods at all installed.  Do you still have docking problems, or not?

If the problem goes away when you uninstall your mods, then that tends to point the finger at a mod as being the culprit.  The next step would be to narrow it down to figure out which one.  Even if you have tons of mods installed, you can narrow it down fairly quickly by doing a "binary search", like this:

1. Run with half of the mods installed.
2. Does the problem still occur, or not?  This tells you which half contains the culprit (i.e. the currently-installed half if the problem occurs; the currently-not-installed half if the problem doesn't occur).
3. Based on that, pick the half that presumably contains the problem, split it in half, and repeat the process.

In this way, you can cut the list of candidates in half with each cycle, which means it'll pretty quickly narrow down to just one, even if you've got a hundred installed mods.

 

The other thing that I'd suggest is to provide more details so that people can help you better.  When you say "doesn't dock", meaning what, exactly?  Does the magnetic docking field engage, or not?  Could you provide a screenshot of two ships trying to dock, where you would expect docking to happen but it doesn't?

[KroShan]

Hi @Caviar ,

docking is one of the fine arts in KSP - it needs practice and patience (i asume that you are pretty new to KSP). My mistake in the beginning was to try it with heavy bulky craft.
There is a great tutorial in the game. It also covers the rendevous part. (I think it also has a too heavy ship to practice docking)

Most important tip is that the dockingports need to be alligned befor trying to dock so one should face 180 the other 0 and so on. Also the speed should be pretty low.

Maybe this helps...

[Caviar]

@Snark

Thank You for the quick reply. I sure would have done the above suggested steps if it the same set of ships have never docked with each other, EVER. But prior to this, it had docked perfectly, and then due to a stupid mistake of mine that's totally unrelated to docking (wrong cargo bay size, mission to capture a rogue floating part in career mode), the ship was severely damaged. So now I reloaded to the prior launch stage, put in the correct size and relaunched it again. But only now it doesn't dock. Plus the port is opposite to the corrected part, so no dependency of the port on the new part.

I would do the bug hunting method you suggested, but lack of free time and the reason stated above are preventing me from doing this.

As for the exact problem, 

This sums it up perfectly. Only "state=PreAttached or state=Ready" doesn't work because its already in Ready position. Plus I'm trying to connect Clamp-O-Tron and CDP Shielded port, which has the same size and shouldn't bother me much.

@KroShan

Thanks for the suggest. I've around 30 dockings under my belt. Would it qualify me as an expert docker enough, master ??   Anyway, yes I have played the tutorial many many times. I'm very comfortable with docking, the process itself is not the problem. It might be the idiotic port acting up. I limit my speed to 0.08-0.1 m/s, and that too is no problem. But whats this angle alignment you are talking about?

Edited May 20, 2017 by Caviar

[KroShan]

Sorry @Caviar, i've been away...

The docking ports shall face the opposite compass point on the navball. If you have to controlable vessels than you can right click on the docking port to 'control from here' than orient it to a point where you know what the opposit is (90vs270; 0vs180; easier: also pointing to the horizon;    zenith-nadir) the easiest is that you orient your docking ports to the normal and the anti-normal marker so that the orientation on the navball doesn't change that much (the navball will only rotate around the axis you are facing while orbiting).

After you have alligned both docking ports select one as a target (distance smaller than ~200m -switch to target vessel - rightclick on the docking port - leave menu open and switch back - select as target) and translate towards it. try not to change the rotation of the craft... to dock perfectly your target velocity marker should be over the target marker.

Edited June 2, 2017 by KroShan