My humble opinion about vehicle-design-restrictions

[HagbardCeline]

...is that logic dictates that the following should work:

And by the way, in the following picture all the green connection balls are in a position that should not break mirror symmetry.

I'm aware that these issues might be deep buried in the underlying systems, but I find this worse of a problem then the fact that a plane with swept wings has the same top speed as one with straight wings.

-HC

[Alshain]

The difference is, Squad can fix the issue with the Plane. Squad can't do a thing about what you want because that is tied to the game's engine which they do not make.

[HagbardCeline]

Doh..., that's what I was afraid of.

[stupid_chris]

I'm not sure I understand what the issue is?

[r4pt0r]

He is saying a tri coupler attached to 3 tanks attached to a tricoupler, should couple at all 3 nodes automatically. the problem being the "tree" system unity uses for parts.

[Redjoker]

Your best option there is to strut the other two tanks to the tricoupler.

[vexx32]

Fuel won't flow that way, though, no matter what you do.

[HagbardCeline]

He is saying a tri coupler attached to 3 tanks attached to a tricoupler, should couple at all 3 nodes automatically. the problem being the "tree" system unity uses for parts.

Yes, but..... it is not exactly the nodes. It's the fact that the fuel flow is dependent on those nodes being connected and that it breaks due to the connection node being way off center.

When I think about it;Both issues could be solved with invisible auto-struts with fuel cross-flow of max length 1cm at the center of the nodes of all two-, tri- and eventual-other-couplers.

-HC

[cpast]

Fuel won't flow that way, though, no matter what you do.

Even if you have a small fuel tank below and connect fuel lines?

[HagbardCeline]

Yea, and this.

Fuel won't flow that way, though, no matter what you do.

The struts say, "No fuel cross-flow" (Emphasis on the cross), the external fuel line says "one way fuel flow", but nowhere does it say that fuel can flow only one direction trough a tri-coupler.

[r4pt0r]

There are workarounds, like placing struts in between the non connecting nodes, and running fuel lines around that mess. but if ever there is a stock fix that makes it easy as pie, I will gift the dev that fixed it a game off their wishlist.

Edited February 14, 2015 by r4pt0r
I AM SO GOOD AT RUN-ON SENTENCES

[stupid_chris]

Yes, but..... it is not exactly the nodes. It's the fact that the fuel flow is dependent on those nodes being connected and that it breaks due to the connection node being way off center.

When I think about it;Both issues could be solved with invisible auto-struts with fuel cross-flow of max length 1cm at the center of the nodes of all two-, tri- and eventual-other-couplers.

-HC

No no no.

Fuel flow works with stack logic. A stack is considered to be all parts that are connected directly above and below a single part. The problem here is because even if the "green balls" line up, those parts are not connected. Even strutting it won't work, it needs a direct connection. This is because of the tree logic KSP uses. Unity also uses tree logic internally for components, but nothing forced the devs to create a tree logic editor.

So yes, it could be changed. But at that point it would be too much of a hassle. Would it be worth it? Yes. But I wouldn't count on it.

[vexx32]

IIRC, the fuel flow logic also won't flow "backwards" through any of the multicouplers, so it probably won't work like that no matter what you do.

[HagbardCeline]

No no no.

Fuel flow works with stack logic. A stack is considered to be all parts that are connected directly above and below a single part. The problem here is because even if the "green balls" line up, those parts are not connected. Even strutting it won't work, it needs a direct connection. This is because of the tree logic KSP uses. Unity also uses tree logic internally for components, but nothing forced the devs to create a tree logic editor.

So yes, it could be changed. But at that point it would be too much of a hassle. Would it be worth it? Yes. But I wouldn't count on it.

The external fuel duct does this, so it can not be impossible. What I am suggesting is that if you line up two tri-cuplers with fuel tanks between, the non-connection nodes will auto-connect due to node proximity(or surface proximity if that is easier*), a two-way fuel-duct(eventually two one way ducts, if a two way is impossible) that has the same strength and rigidity as the connected node.

Also i have tested the the fuel-flow is not dependent in the green balls connecting: Surface-stacking one full and one empty liquid fuel fuselage side-by-side, and connecting the engine to the empty one does give you a running engine. And contrary to liquid-fuel the air form the air-intakes will pass though a stack of tri-couplers like in the 2nd picture in my opening post.

-HC

[Sean Mirrsen]

The inverted multicoupler issue the devs know about, and after the advent of multi-docking it was said that there is technically nothing preventing the feature from being added now, besides the required effort to make sure it works. Maybe a properly formatted suggestion thread (or, as the joke goes nowadays, maybe a Reddit thread?) would help remind them of it?

The fuel flow not working for the inverted tricoupler is an entirely different issue, and that is actually set per-part, and was intentionally made to work that way, because... well I can't remember the specific problem offhand, but it had to do with fuel logic. Something about asymmetric fuel draw.

[HagbardCeline]

I was wrong about the surface-stacked-tanks, must have been half asleep when i did that test. Tried now, and it did not work.

But one other fact, if you manage to connect a external fuel duct to the lower part(original upper) of the upside-down tri-coupler; the fuel will flow the rest of the way (out of the original top end)by it self.

Edited February 14, 2015 by HagbardCeline

[Captain Sierra]

TO the OP:

THe whole multiadapter confusion is basically this. STACK attached tanks cannot flow from the multi side to the single side, but since fuel lines are radially mounted, they circumvent that flaw.

THe issues you describe are artifacts of the Unity part tree logic. To rectify it, Squad would need to write their own logic from scratch to replace the Unity default. That's a lot of work as you can probably guess. Would it be worth it, very much so. Can we expect to see it? Probably not for a good while if ever.

While not stellar, "If it ain't broke don't fix it" still applies because it does work, albeit not as well as it could.

[r4pt0r]

What if it was coded so that when the green nodes in the VAB intersect with another green node, the game places something akin to invisible struts. struts are allowed and don't break the tree structure. That would let people easily connect tricouple to tricouple for example, at all 3 points. The real connection and the added fake ones. though fuel flow would still need some work...

[Red Iron Crown]

Even in a multi-docking port arrangement, only one of the connections is the "true" connection that will allow fuel flow (or at least that was so the last time I tested it a few versions ago). The other issue is that performance is greatly impacted by parts that make loops in the vessel tree; IME a strut or fuel line has about the same impact as three or four regularly attached parts.

The struts say, "No fuel cross-flow" (Emphasis on the cross), the external fuel line says "one way fuel flow", but nowhere does it say that fuel can flow only one direction trough a tri-coupler.

That's how they work, though. The relevant line in the .cfg file is "NoCrossFeedNodeKey = bottom".

Edited February 14, 2015 by Red Iron Crown

[Tuareg]

The difference is, Squad can fix the issue with the Plane. Squad can't do a thing about what you want because that is tied to the game's engine which they do not make.

omg. there is no programmatic blockage in the gameengine to make either of those stuff working... it would just need some programming actually from squad

Edited February 14, 2015 by Tuareg

[HagbardCeline]

What if it was coded so that when the green nodes in the VAB intersect with another green node, the game places something akin to invisible struts. struts are allowed and don't break the tree structure. That would let people easily connect tricouple to tricouple for example, at all 3 points. The real connection and the added fake ones. though fuel flow would still need some work...

I was trying to say about the same thing here;

Yes, but..... it is not exactly the nodes. It's the fact that the fuel flow is dependent on those nodes being connected and that it breaks due to the connection node being way off center.

When I think about it;Both issues could be solved with invisible auto-struts with fuel cross-flow of max length 1cm at the center of the nodes of all two-, tri- and eventual-other-couplers.

Only I'm almost shure that struts and external fuel ducts are about the same thing in the code, so It should be able to solve both the connection and the fuel flow.

-HC