Rules for connecting nodes in VAB?

[AndreZero]

I can't quite figure out what the rules are for when you can and can't connect things in the VAB. I was trying to connect two Rockomax HubMax Multi-Point Connectors and the new one was highlighted in red. I rotated it and it turned green. As far as I can tell, all six sides of the multi-point connector are identical but apparently there is something different that was preventing them from joining.

Here is a sample of them not matching:

and here they are after I rotated the new part

Am I doing something wrong or is there something obvious I'm missing?

Edited February 18, 2015 by AndreZero
marked as answered

[Renegrade]

Well, that's the way it works. The top node (and possibly bottom?) is special in some manner... I think you'll need an expert part modder to answer the 'why' part.

[lextacy]

If you look into the part file they have 6 nodes , but the game only activates node_stack_top and node_stack_bottom

[Supernovy]

As far as I remember, it has to do with the order of nodes in the config file. All nodes can be attached to, but only either the last two or first two (I forget which) can be attached by.

[AndreZero]

As far as I remember, it has to do with the order of nodes in the config file. All nodes can be attached to, but only either the last two or first two (I forget which) can be attached by.

Ah. That makes sense. I guess it makes sense that there are certain nodes that can't be attached by but it's not intuitive/obvious, is it? Thanks for the answer.