Start with the basics; import a 1x1 basic floor tile from the game you're working for. Then use that tile's basic dimensions to guide your project. From here, start making your pieces. Build out your walls to a multiple of the floor tile's dimensions. I'd first sketch out the general style I want for my piece, then eventually use this guideline to build individual ornamental pieces to spruce up the kit with later on (for example, Dwemer tileset's gears, pistons, cupboards, etc). Also, when building your kit, make sure you turn on snapping in the 3d editor you're using, and adjust the tiling values to correspond to Skyrim's. For every tileset you usually need: Halls 1wayhalls (wall on either side with roof) 2wayhalls (hallway that bends at a 90 degree) 3wayhalls (hallway that bends at a 90 degree, but allows 3 ways of traversal) 4wayhalls (...) halltodoorpiece (piece that converts from hallway to room - one of its walls would be able to align to roomwallentrance*) hallwayend (a 1 way hall piece, much like the 1way but capped at one end) and Rooms roomwall (side wall + floor + roof) roomwallentrance* (side wall but with door shaped piece inside + floor + roof) roomcornerin(2 side walls at 90 degree angle, turned in + floor + roof) roommid (basically floor + roof) Have a look at what Bethesda did with their kits. Ofc course you can do a lot more depending on what you need. You can make iterations on this whether you want bigger halls, which then you increase the multiplication factor, or smaller tighter ones depending. But most importantly, the dimensions of all these pieces need to be exact to the reference scale we used earlier. After you've done the basic grey box kit, then you can move on to uniformly arting them up, adding in all the bells whistles and making variations. This is by no means THE way to do it, but its the way that works for me. You could also fully art up the individual building blocks first, ie make fully completed wall pieces, floor pieces, roof pieces, ornaments, etc and then use those to build your kit instead.