Why can't I get the new subassembly system to store my craft?

[Dunbaratu]

I'm trying to use the new subassembly feature to build the payloads as separate subassemblies - rovers, landers, habitats, etc, with the intent of adding them to the tops of rockets later.

And I just can't make it work. Every time I do it I seem to be only able to store parts that don't include the command core, which is pointless as the command core is the center of the craft with everything attached to it.

Any time I try to include the command core in the subassembly, the game (quite incorrectly) claims the assembly has no attachment point, which is utterly false as the design has docking ports meant to be used when attaching to the rest of the rocket.

Edited October 21, 2013 by Steven Mading

[-ty-]

Like you said, the command pod isnt allowed.

So dont have it!

Picture a rocket with a command pod on top, two orange tanks below, and a mainsail attached.

Pick up the top orange tank, (along with it, the bottom tank and the engine) and drag them to the sub assembly to save it. It's that easy.

This means that if you have parts attached above AND BELOW the command pod (like your rocket below, and an escape ladder above) you'll have to save them as two separate sub assemblies. A crown piece, and a bottom piece.

Also, the game is not incorrect in saying that the craft has no attachment points, as docking points are not considered attachment points. You've picked up the command pod, which indicates that that is the main piece. That piece has no attachment points. In my example, the orange tank that you plucked off, does have some.

[Dave Kerbin]

This seems to be a limitation of the current tree based build system. The root of the tree is your core, the first part you placed down, and everything must branch out from that without looping back. If you detach a group of parts (for example a T400 stacked on a T800) you'll notice you can't rejoin it to the craft except by the root most part of the group, the T400.

Because when you start a new ship you always start with a trunk you can't load an assembly that has a trunk itself, and so the game prevents you from saving one like that either.

The way around it is to start with a dummy core. For example if you want to build a lander (which you will reuse as a subassembly) composed of a Mk1 pod, T400 fuel tank and LV-909 engine which will mount onto various rockets with a decoupler then start with a dummy probe core. Place a decoupler on top of the probe core, then the engine the fuel tank and pod. Detach the group at the decoupler and save it as a subassembly.

Keep in mind that when you start your rocket that you will later attach this subassembly to you don't need to start with a command pod anymore, most non-radial parts are now accepted as the ships 'core'. So just drop down an orange tank (your 'core'), attach a mainsail and then drag your lander subassembly and stick it on the top.

Edited October 21, 2013 by Dave Kerbin

[Dunbaratu]

Also, the game is not incorrect in saying that the craft has no attachment points, as docking points are not considered attachment points.

That is false. They have the green balls that indicate the attachment points.

The problem is that the error message is lying to me. It's not the lack of attachment points that's the problem. It's got plenty of them. It just wants the attachment point to be at the HEAD of the part tree and not the leafs of the part tree. It's a misleading error message.

[Dunbaratu]

This seems to be a limitation of the current tree based build system. The root of the tree is your core, the first part you placed down, and everything must branch out from that without looping back. If you detach a group of parts (for example a T400 stacked on a T800) you'll notice you can't rejoin it to the craft except by the root most part of the group, the T400.

The dummy core idea fixes the problem. Thank you. The real problem is that the error message is extremely misleading. When it says there's no attachment point that's false. There's plenty of them. What it should have said is that it needs an attachment point at the ROOT of the part tree rather than at the leafs of it. That error message, while it might confuse some people who don't know about the tree structure, would have immediately made it clear to me what was going on. Simply telling me there's no attachment point when there's clearly LOTS of them just didn't help at all.

[-ty-]

Well, this is supposed to be second nature to you after playing for only a few minutes. You realize that you can only attach objects to one another with the attachment points of the object you picked up. The "root" object. If you have a stack of tanks, and you pick up the top-most tank, with all the others below it being selected, then you can only attach that selection with the attachment points of the TOP tank.... so the inference isnt too hard to make that since you, the player, can only attach parts with the root's attachment points, the subassemblies will work in a similar way. IE., command pods wont work.

I hope it doesnt sound like im trying to sass you, because im not.

[HeadHunter67]

If only it were as simple as you make it sound...

I'm well-acquainted with root parts and subassemblies as far as the plugins from previous versions. In 0.22, I made a lifter with a decoupler at the top and saved it as a subassembly. When I tried to attach it to the bottom of my CSM, it simply wouldn't attach. So if this system is supposed to be "intuitive", it's failed miserably.

[Dunbaratu]

Well, this is supposed to be second nature to you after playing for only a few minutes. You realize that you can only attach objects to one another with the attachment points of the object you picked up. The "root" object. If you have a stack of tanks, and you pick up the top-most tank, with all the others below it being selected, then you can only attach that selection with the attachment points of the TOP tank.... so the inference isnt too hard to make that since you, the player, can only attach parts with the root's attachment points, the subassemblies will work in a similar way. IE., command pods wont work.

I hope it doesnt sound like im trying to sass you, because im not.

But that's an utter non-sequitor. The fact that you need an attachment point does not imply you can't use a command pod. Other than the stayputnik, all the command pods have at least 2 attachment points on them, so you can have an assembly dangling off one of the attachment points and yet still have an open attachment point on the other end of the command core. If you can't use a command core as the root of a subassembly, that fact is NOT something you can automatically assume from the fact that the root part needs an open attachment point.