Help with a landing craft for a mobile base (two docking ports)

[Casen]

Hello all. I have made a giant mobile base truck with room for like 40 kerbins.. It even has 4 balcony rooms.. Moving on, After designing the truck, I went ahead and designed a landing mechanism. The truck itself weighs 40 tons so, I decided to use two docking ports on the roof for extra strength and because they fit my design best.

From there I put a long girder sticking straight up from each port and then tried to connect the two with a third girder, but could not get a "snap into place". I did, however, get a green spot with the top piece inside the other part. Cool I thought. I then put struts going back and forth from the left to the right girders, and all the horizontal bits.

I made this extremely sturdy, no wobble at all except from the ports themselves, which i have anchored into the roof with even more struts. Cool, it all stays together and works. Awesome.

So, I set up action groups on the docking ports themselves. I had two options "Decouple" and "Undock". I have no idea what the difference was between the two, so i put one on a different number to try them both. So, I take my new creation out to the runway to test the flight characteristics (meh) and the landing/docking abilities. It is strong enough to lift off and fly around at around half throttle, and then to land on its legs with the parachutes and whatnot. My problem is when I go to undock/decouple the truck from the lander. When I undock/decouple, every single strut that I had connecting the left side to the right side just disappears. And the girders that i though were holding it together come apart.

This is a problem as I wanted to be able to re-use the lander to change moons and whatnot when i get it out to other planets. Does anybody have any advice or corrections in my building method of how to attach the docking ports?

The ones on the truck I put in symmetry mode, then I placed the other ones, still in symmetry mode, docked to the ones in the truck in the space plane hangar, then I added my girder segments.

Any help would be appreciated.

Edited July 11, 2013 by Casen

[Darren9]

I don't think there is any way you can connect the two upper halves - the game doesn't allow it, you can't build off of two ports and connect those two separate "trees" in any solid way, only put struts across which will vanish when you undock. Either use one docking port or build the upper half separately with two ports sticking down that line up to the ones on the rover and launch them individually. Quantum struts will come in handy if you make two separate vehicles - you'll be able to link struts once you've docked.

[NoMrBond]

You might actually need to make it as two separate craft, and dock them together outside the VAB

[Colonel_Panic]

You have to build the upper portion as one segment, via connection from only one docking port. Then, you can build the second docking port to connect to the base. Warning: unless the docking port is PERFECTLY aligned, it will not connect. Furthermore, it may not start out connected on the launchpad: it may be necessary to dock it in space.

[Casen]

Well poop. Thank you for the help, Im now on my way to re engineering everything