Behold the Bay Door. It is the portal between the realms known as "Inside" and "Outside". Read on to learn how to manipulate Bay Doors into serving your purposes.
1) Since structure diagrams are displayed in 2-D, the Bay Doors are measured by their overall volume rather than by their dimensions. Thus, Bay Doors use hull space, and in order for a unit to use a Bay Door, the Bay Door must have more hull space than the unit. For example, if you have a tank with 540 hull space, then the Bay Door must have at least 540.01 hull space or the tank will not be able to use it.
2) The Hangar must also be larger than any given unit that will use it. If you have a structure with only one Bay Door, and the Bay Door is large enough for your unit, but the Hangar is not, then the unit will still not be able to travel between Inside and Outside. Therefore, as an absolute minimum the Hangar should be as large as the sum of all the Bay Doors. Otherwise you end up with useless Bay Doors. Typically you will want to be able to dock more than one unit per Bay Door at one time. Also consider that units being built will go in the Hangar before they auto-launch, if you have auto-launch on.
3) Bay Doors have a 30 second reset timer before they can be used again. Therefore, if you need to launch a number of units simultaneously, you need several Bay Doors, and each of sufficient size.
4) Units use Bay Doors sequentially. This means that if you have six Bay Doors, units will use Bay Door 1 first, then Bay Door 2, etc. If you have multiple Bay Doors of different sizes, it is helpful to number them starting with your smallest up to your largest. This way fighters will use your smaller Bay Doors first. If you number them the opposite way, then if you launch one fighter, it will use your largest Bay Door, preventing its use by larger units for the duration of the timer.
Keep these guidelines in mind to help avoid creating any more useless Hulls that can't be deleted than you have to.
