This post explains how to build a minecraft castle using the fill and clone commands. The first part is a very simple tutorial on the commands themselves, while the second part explains how to use the commands to build the castle. If you are familiar with the commands already skip to the second part of the post.

Fill and Clone Basics

Minecraft coordinates are written out as sets of three numbers. For example: 6 5 9. The middle coordinate (the y one) tells you how high the location is. A positive x coordinate tells you how far east you are from an arbitrary location of x = 0, and a negative x coordinate tells you how far west you are from that same place. A positive z coordinate tells you how far south you are, and a negative z coordinate tells you how far north you are from that same place. To find out the location of the block (or empty space) you are looking at us the F3 button.

To do the fill command you type in the coordinates of two corners of the rectangular prism you’d like to fill. So if you wanted to create this lovely stack of emerald blocks, what you would need is the coordinates of where you want to place the two corners I have marked out with the arrows.

Try teleporting to 0 4 0 on a superflat world, and typing /fill 1 4 1 3 5 2 emerald_block. The first three numbers tell the coordinates of one corner of the shape, and the second three numbers are the coordinates of the other corner.

You can get rid of the shape easily. Press / to be able to type a command but then instead of typing a command press the up arrow button to bring back the last command you had typed. Now erase “emerald_block” and write “air.” Click enter and what you built is replaced with air.

But now put the emerald blocks back to practice cloning. For cloning you need three sets of coordinates. The first two tell the corners of the rectangular prism you want to clone, and the third set of coordinates tells the first corner of where you want to place your clone.

Try /clone 1 4 1 3 5 2 10 4 8 You’ll notice of this string of nine numbers that the first six are the coordinates for the emerald blocks I just had you make. The third set of coordinates are not too far away.

To practice place six gold blocks on top of the original set of emerald blocks. Now try cloning the emeralds and the gold. You can use almost the same string of numbers as before, but you need to change the one that controls the upper height of what you are cloning. That is the y coordinate of the second set of coordinates, or in other words, the fifth number from the whole list. Try altering it one higher, and doing the clone. Did you get the emeralds and the gold?

Now try to clone the whole thing up in the sky. Change the y coordinate of the third set of coordinates, the one that controls where the new creation will be placed.

Building the Castle

This castle is built by creating rectangular prisms of stone and then hollowing them out with rectangular prisms of air inside.

The first thing to do to build this castle is to open a superflat world and teleport to 0 4 0. All of these instructions can be altered to use with a different terrain and different location, but it is simplest to practice it first on a superflat world.

The Lower Part of the Walls

Type in: /fill 1 4 1 90 7 90 stone (This creates a giant rectangular box of stone.)

Now type: /fill 2 4 2 89 6 89 air (Your rectangular box has become hollow inside.)
/fill 5 4 5 86 6 86 stone
(There is now a smaller stone box inside the hollow box.)
/fill 6 4 6 85 7 85 air
This builds the lower walls around your castle.

Upper Part of the Walls

The walls are pretty boring, so you’ll want to decorate them. There are a lot of possibilities. If you want to have a simple thing wall on top of the walkway, you could use: /fill 1 8 1 90 8 90 stone and /fill 2 8 2 89 8 89 air but probably you’ll want something much fancier. Maybe you want a pattern with one block then one missing, or with a combination of mossy cobblestone walls with cobblestone walls. Teleport yourself to 1 9 1 and start building the wall you want along the x axis. To start with I choose a pattern that stretches three blocks long and two blocks high. After doing one sample I typed /clone 1 8 1 3 9 1 4 8 1. That takes the three blocks and clones next to them. Now my wall stretches out six blocks long.
I have two options for how to keep cloning the wall.  The first is to continue to clone three block long stretches over and over again. Using the up button I can recall what I had typed in and change the seventh number to 7 (the next empty block next to my partly built wall), and then again changing it to 10, and so on and so on, each time raising the 7th number to one number higher than the next multiple of three.
My second option is to clone progressively larger parts of the wall at a time. So after I cloned the pattern once (and thus had a wall six blocks long) I used /clone 1 8 1 6 9 1 7 8 1 to clone six blocks at once. After that I cloned twelve blocks at once, then twenty four.
You can figure out where to clone it to by walking along what you have already done, or you can do it using math and logic. If you made three blocks, cloned them once, then cloned six, your wall now stretches twelve blocks (3 + 3 + 6). It starts at 1 8 1, continues to 12 8 1 and then your next clone needs to be placed starting at 13 8 1. It will stretch out to 24 8 1, so your next clone after that can be /clone 1 8 1 24 9 1 25 8 1
Whichever way you decide to clone the wall, once you’ve completed the whole wall clone to the walkway parallel it. /clone 1 8 1 90 9 1 1 8 90.
Then turn and work on the wall that stretches along the z axis. It is easiest again to start at 1 8 1, put three blocks in then /clone 1 8 1 1 9 3 1 8 4.

The Automatic Minecraft Castle Towers

Do you want a tower at the corners of the walls? A basic tower can be easily built.
/fill 1 8 1 5 12 5 stone
/fill 2 8 2 4 10 4 air
/fill 2 12 2 4 12 4 air
Personalize the tower a bit (remembering that when you duplicate it, you cannot rotate it) and then duplicate it to the other corners. If your tower fit on the wall and didn’t overhang, try the following adjusting the fifth number higher if the top of your tower stretches above y = 15.
/clone 1 8 1 5 15 5 86 8 86
/clone 1 8 1 5 15 5 1 8 86
/clone 1 8 1 5 15 5 86 8 1

The Automatic Minecraft Castle Keep

Four more lines of text give you your keep. They are:
/fill 35 4 35 65 9 65 stonebrick
/fill 36 4 36 64 8 64 air
/clone 35 4 35 65 9 65 35 10 35
/clone 35 4 35 65 9 65 35 16 35
Presto! There is the rough of the castle. Of course it is very, very rough. You will need to build a gate, gate house, doors, furnishings and all types of other things but for a quick start to a giant castle nothing beats using the fill and clone commands.

Once you get used to using the clone and fill commands there are lots of things that can be built quickly. It is easy to start picturing minecraft houses as prisms of air inside prisms of wood or stone. Though the keep above has only three big open floors, it is possible to plan out a more complicated collection of “bubbles” or “rooms” inside.  Try using the following three commands and then designing your own rooms by number.

/fill 35 4 35 65 9 65 stonebrick
/clone 35 4 35 65 9 65 35 10 35
/clone 35 4 35 65 9 65 35 16 35

To hollow out the downstairs from solid rock into two rooms try:
/fill 36 4 36 44 8 64 air
/fill 46 4 36 64 8 64 air