Placeable object help please.

[jbb]

This is annoying me now :
I have this

which doesn't look too bad. Much of that geometry is placable objects placed right next to the main world object. But there are some objects in mid-air.

And then there is this:


Where the doors seem to be exactly 90degrees in one axis out. They are facing the middle of the room, not across the doorway.
Maybe I need to rotate one of my axis by 90degrees.