Radial decouplers - why don't they work?

[alkopop79]

I love KSP but got to a point where I cannot progress and the game is unplayable. Whenever I attach a stage to the main stage, such as a solid booster, it 'sticks' on the surface and cannot be jettisoned. Believe me, I've tried everything such as trying to attach the boosters with snap mode on and off. Worse, I have to check the sequence every time to make sure the radial decouplers work which takes time. I got to a point where I can't do more missions in career mode. Also, the larger decoupler (Hydraulic Detachment Manifold) never worked! I've tried dozens of times and it sucks. Again, I love the game but the fact that basic things lie the decouplers don't work makes me very angry. Any ideas? Fixes? Maybe third-party libraries with decouplers?

[SSSPutnik]

Sometimes attaching tanks to decouplers can be a pain.

Check:

A) The decoupler is not too high or too low in relation to the mid point of the tanks.

I assume you are adding in pairs or more, you will find they prefer to stick too the main tank. Rotate them and move up and down till they stick squarely to the decouplers.

It can be frustrating but I find point (A) can be a roadblock.

[Deadweasel]

It's just a simple lack of experience. Attaching items to a radial decoupler is a real pain sometimes, but once you get the eye for what it looks like when properly mounted, you'll have less trouble with them eventually.

The trick is to use snapping, and remember that the virtual "cylinder" that the part rotates around on the decoupler is very small. Use very careful and tiny mouse movements, and when you think you've got it and dropped it, rotate the camera so you're looking down or up along the join. If it's not dead-center of the decoupler and sitting on top of it, you'll need to do it again.

Once you've got it, save it as a subassembly so you can just drag it in for another design later, without all the hassle of mounting to the decoupler first.

EDIT:

Also, to back SSSPutnik's info:

When placing a part, watch the mouse pointer, not the part. The pointer is what is being referenced when positioning your parts.

[alkopop79]

Sometimes attaching tanks to decouplers can be a pain.

Check:

A) The decoupler is not too high or too low in relation to the mid point of the tanks.

I assume you are adding in pairs or more, you will find they prefer to stick too the main tank. Rotate them and move up and down till they stick squarely to the decouplers.

It can be frustrating but I find point (A) can be a roadblock.

Awesome, thanks!

[alkopop79]

It's just a simple lack of experience. Attaching items to a radial decoupler is a real pain sometimes, but once you get the eye for what it looks like when properly mounted, you'll have less trouble with them eventually.

The trick is to use snapping, and remember that the virtual "cylinder" that the part rotates around on the decoupler is very small. Use very careful and tiny mouse movements, and when you think you've got it and dropped it, rotate the camera so you're looking down or up along the join. If it's not dead-center of the decoupler and sitting on top of it, you'll need to do it again.

Once you've got it, save it as a subassembly so you can just drag it in for another design later, without all the hassle of mounting to the decoupler first.

EDIT:

Also, to back SSSPutnik's info:

When placing a part, watch the mouse pointer, not the part. The pointer is what is being referenced when positioning your parts.

Thanks dude, I managed to attach asparagus stages and they work perfectly.

[alkopop79]

By the way, has any of you guys managed to successfully use the larger radial decoupler? I never managed to get it work...

[Deadweasel]

By the way, has any of you guys managed to successfully use the larger radial decoupler? I never managed to get it work...

I have quite a few times, but it's even more dog-tricky because there's no elevation reference (you can't see it "snapping" higher on top of the decoupler). They're actually how I thought to start checking the alignment by looking down between them vertically before assuming all was good.

You bet your beef that when I got one working, that sucker was an insta-save in the subassembly folder!

[SSSPutnik]

I almost always use the large radials, makes spacing wide enough to see!

They also decrease likelihood of impacting rest of your ship when dumped.

Place them looking square on sideways and rotate till you see the tanks go green and "bloat out" ie move away from the center. You know then that they are at least partially attached, then work on getting em square.

[Monkeh]

The key is to remember it's your mouse pointer that is the attachment point. Line up with the detachment manifold and slowly raise up or down in the centre.

I use the detachment manifolds all the time, no problems.

[alkopop79]

Thanks guys, just managed to land on the Mun and get back to orbit. Getting back to Kerbin is the next challenge.

[SSSPutnik]

Yeah my first munar kerbonauts got stuck in munar orbit, had to send a rescue ship.

[technion]

Alkopop you're 90% of the way there. One tank and one small engine can make that return trip - just remember the parachutes!

[celem]

Yeah each of the radial decouplers in the game has a 'trick' to it. Once you learn to recognise what each one looks like when properly mounted they do all work just fine.

The hydraulic manifolds in particular are nasty, they lie very flat and can be hard to inspect in dense asparagus setups. The thing here is to get one working, test it on the pad, then to sub-assemblies with it. Make a point of learning this one, they are very useful for heavy stages.

For the manifolds the tank wants to be as centered as possible, check to see how much of the decoupler itself is visible on either side.

For the short and long spacing radials do a rotate-around and check. The black bar of the decoupler itself should be vissible. If you only see the little black studs/supports on the short ones or only the strut-like frame on the longer ones then its wrong and is clipping. Look for the vertical black 'bar'.

[Roxette]

I've found the most consistent way to place things on any of the decouplers is to pick up the part, use W to turn it horizontal, then place and hold the mouse pointer exactly over the centre of the decoupler, then S to return the part to correct orientation and click to fix. Also if later re-positioning is needed, pick up the tank/booster and its decoupler together as a unit (maybe that's obvious now, but in the early days... .

[Vanamonde]

The large radial is just about the only one I use. The gap it provides is usually wide enough that no sepratrons are needed.

[capi3101]

The large radial is just about the only one I use. The gap it provides is usually wide enough that no sepratrons are needed.

Which one do you mean, the TT-70 or the Hydraulic Manifold? I've had mixed results with both.

[Kasuha]

When placing a part on radial decoupler:

- put the decoupler on the body of your ship

- adjust your camera so you have a good view at the decoupler and do not move the camera after that. Remember where the rectangle of the decoupler's attachment surface is on your screen. You can put your finger on that place on monitor to better remember that

- drag the part to be attached so your mouse cursor is over that rectangle. It may be a bit tricky since you don't see the decoupler due to the part anymore. But if you have your finger there it becomes much easier.

As long as your mouse cursor does not exit the rectangle of the decoupler's active surface, you're placing the part on the decoupler. Anywhere else it will stick right to the body of the ship. So you have only limited freedom (particularly vertically) where you can place the part. If you need it higher/lower, you need to move the decoupler.

[kzauner]

For the short and long spacing radials do a rotate-around and check. The black bar of the decoupler itself should be vissible. If you only see the little black studs/supports on the short ones or only the strut-like frame on the longer ones then its wrong and is clipping. Look for the vertical black 'bar'.

Maybe nobody has noticed, but the part you are attaching to is highlighted in the staging-strip. So - if unsure. before you 'click' it on, glance on the decoupler-icon in the staging-strip (right side of the screen). If it's highlighted, you are snapping the Tank/whatever to said decoupler with your next left-click.

HTH

[Vanamonde]

Which one do you mean

Yeah, the TT-70. The one that looks like a little trestle bridge.

[John FX]

You should mark you question as `answered` now (edit your first post)

[Jeltz]

I have tried all the suggestions posted above. They help a bit but IMHO all are workarounds at best. The OP is correct to raise this as something KSP needs to improve upon.

Here is a scenario i have not been able to get to work: on long Mk3 tank. 2x structural radial decouplers on one side (one is clearly not enough to resist rotational moments). Now try to attach another Mk3 long tank to both decouplers. Insanity results! 

Looks fine until you launch and you find one not attached, and one is not enough to give the craft structural stability. Same problem if you use 2xMk3 normal tanks stacked - getting both pylons plus the axial intertank connect is really hard. And yet it can be done! I think I get it right about once in 50 times - so frustrating, even with the hints given here. So here is my solution (if KSP is reading) 

It is my view KSP should take a leaf out of some of the 3D CAD programs like Solidworks (including using the mouse wheel for zoom  - why is it up/down for construction but zoom in/out elsewhere in KSP? but that is a story for another day.) These CAD programs use the concept of a mate which is implemented only partly in KSP - that is the green/black ball. Every part should have all attachment points and only the attachment points indicated by green/black balls - for circular symmetry these can be proceduraly generated as required on the part if available depending on the degree of symmetry chosen. Then it is a simple matter of clicking a green ball, shift clicking another ball and mate! Any other balls that then overlap also mate, and if done correctly, visible bits of the two parts can never overlap (an overlap test would not go astray in KSP either, but I do confess to making some insanely funny rockets with congruent parts!) 

Back to mates - this idea that all connections go through mates also permits simple generation of the structural support tree needed to realistically simulate stress and failure in an interconnected structure.

Finally get rid of the part move/rotate/reroute menu.  right click mouse gives the camera view and its rotation options (you could consider left click drag to go from rotate to translate). Holding down left shift should simply switch to moving/rotating the part instead of the camera. All done. Clean and simple.

Edited November 3, 2016 by Jeltz
minor factual correction

[Plusck]

1 hour ago, Jeltz said:

I have tried all the suggestions posted above. They help a bit but IMHO all are workarounds at best. The OP is correct to raise this as something KSP needs to improve upon.

Here is a scenario i have not been able to get to work: on long Mk3 tank. 2x structural radial decouplers on one side (one is clearly not enough to resist rotational moments). Now try to attach another Mk3 long tank to both decouplers. Insanity results! 

...

It cannot work because in KSP, each child part can only have one parent.

In your example, the Mk3 part is parent to the decouplers. The tank you are trying to attach is the child to one of those decouplers. The other one doesn't attach at all.

The CAD program you're talking about cannot have a pure "tree" structure if it allows multiple connections. Or it has a tree structure and only one of the connections is "real", while the others are similar to struts in KSP. Changing KSP to do what you're asking it to do would be fundamental rewrite of the whole game.

That is why you need to use struts. They are attached only to their parent part (where you place them) but allow a structural link to another part (as long as that other part stays on the strut's tree... if the other part is separated, the strut severs immediately).

[Vanamonde]

This thread is 3 years and umpteen game versions old. Therefore, @Jeltz, the cause of the OP's problem is unlikely to be the same as yours. Feel free to start a new thread on the subject, but this one will now be closed to avoid mixing new and obsolete information.