I wasnt gonna post screenies until i had pretty much finished. But i need a bit of help and i cant resist.
The boosters are pretty much final, i added som lighting and they look alot better

Green and red lights you say?

This is where the troops are gonna sit

Now to my problem, i would go to the help center but im sure its a simple answer. I checked a load of tutorials but they all seem to skate over where im struggling.
You see here

Basically i want a double rotating door (like normal real doors). My problem is that i do not understand how to use the origin brush (which is essentially where the hinge is).
As you can see in the pic, the top left corner of the door is see through. I origin'd that whole lenth of the door, as thats where i want it to hinge. I then textured all the faces, except the top and bottom. i thought this would work nicely, but that top corner dissapears.
HOW DO I USE THIS ORIGIN THINGY?