That's the interior of a ship I have to fill, that I've been designing for weeks a little bit at a time. I have the overall structure mostly done, including a framework built from blast wall blocks. Also done is the missile bay, which fires some rather large guided missiles that have already been tested to working condition.
The design will be for a Survival-functional heavy battleship. Right now, from front to back is about 390 meters(1 large-grid block = 1.5m), and that screenshot is just inside the missile bay, 190m from the front of the ship.
It is intended to mount these:
A 50m-long gravity cannon, though I may have to cut that down if I plan to use them, as each is nearly half as long as the ship is wide, with a planned 16 guns(4 each side, top and bottom). The projectiles they fire are devastating, capable of punching through significant armor, while also fragmenting into several rods of blastwall inside the target, causing destruction if the target tries to maneuver with them inside. The reason for that is because of what might have been a re-work of collision physics, the impact hits with enough force to destroy all the other blocks on the projectile
except the blastwall rods. Cutting down the cannon length might reduce the velocity(currently throws it with 16g's of force), though.
The tricky part is now to fill all that space. Much will be devoted to cargo, as those cannons and the missiles will take quite a bit of resources for ammo. The cannon slugs alone have 3 artificial mass blocks(27 gravity generator components!). I suppose if I have to cut down on the cannon length, I could reduce the size and artificial masses of the slugs. But anyway, a few spaces are already planned. The upper fore part of the ship, where many would expect to find the command bridge, is actually going to be the brig. The command bridge itself will be more towards the center of the ship, to best protect the most important part from attack.
Other features include an already-built small hangar with two support fighters and a utility shuttle.