If you are using a 3D tile based kit to build your scene, then you may find this small tool useful.
Don't have to line up two tiles or rotate them to the right angle manually any more!
Just select an prefab (such as a wall tile) from Assets folder and input the room size, this tool will automatically create a group of wall/corner/floor/window base on the tile you choose.
I create this because I need it, please review and tell me the feature you'd like to add, I will try to improve it.
Icon by www.kenney.nl
Screenshot using 3DForge's Village Interiors Kit.