Minecraft Arch Generator

An arch is a curve over an opening: a doorway, a gate, a window, a tunnel mouth or the span of a bridge. On a block grid the curve becomes steps, and the steps have to be even on both sides or the arch leans. The Minecraft arch generator does that counting for you. It fills every block whose centre lies inside the curve, then keeps a ring of the thickness you ask for, the same way the circle generator outlines a circle. The curve of a one-block round arch is exactly the top half of a thin circle.

Minecraft has no structural physics, except for falling blocks such as sand and gravel, so an arch is about how it looks and not about holding weight. That frees you to choose any width and height, and to make the ring as thick as the wall around it.

A round arch is half a circle. Its curve rises half the width, so a 15-wide arch has a curve 8 rows tall; anything taller than that gets straight sides under the curve, which is what the 12-tall example above has, 5 rows of them. A pointed arch, the Gothic shape, is two arcs that each have the width of the opening as their radius and meet in a point at the top. It needs about 87% of its width in height, so 15 wide needs at least 13 rows. An elliptical arch takes its width and its height separately, like the oval generator, so it can be low and wide for a bridge or tall and narrow for a window. When you enter a height that is too low for a round or pointed arch, the plan raises it to the lowest possible height and tells you.

1. Enter the outer width. This is the full width of the arch from the outside of one side to the outside of the other, including the ring itself.
2. Enter the height. Height counts from the ground to the top of the ring.
3. Choose the curve. Round for doors and bridges, pointed for gothic windows and churches, elliptical for wide, low spans.
4. Set the thickness. One block is a thin outline; two to four blocks suit gates and bridges. The clear opening in the stats shows how much room is left inside.
5. Set the depth. Depth is how many blocks the arch runs back into the wall or along the tunnel. The total in the stats is the front plan times the depth.
6. Build from the bottom row. Click each block on the plan as you place it, or step through the rows table.

• Doorways and archways from 3 wide and 4 tall, with a one-block ring, in stone bricks or cobblestone.
• Castle gates around 9 wide and 11 tall with a ring two blocks thick, run 2 blocks deep so the gate reads as a passage through a wall.
• Windows 5 wide and 8 tall, or a Gothic window 7 wide and 14 tall that takes 27 blocks.
• Bridges: a round arch 21 wide and 11 tall with a ring two blocks thick takes 56 blocks a slice, and 280 blocks at 5 blocks deep. Repeat it along the river and lay a deck on top.
• Tunnels and colonnades made by setting the depth to 10 or 16 and placing arches side by side.
• Wide oval arches for aqueducts: 31 wide and 10 tall, two thick, takes 68 blocks a slice, 204 at 3 deep.

On a pointed arch an odd width ends in a single block at the peak, the keystone, which you can build in a different block for a classical look; an even width ends in two. To smooth the steps, swap the outer corner block of each step for a stair block, with the tall side facing away from the opening; the plan counts full blocks, so the totals stay the same. Because the arch is symmetrical, build one side and copy it to the other. For a bridge, make the ring at least two blocks thick so the span looks heavy enough to carry a road.

Download the arch as a .litematic file to paste it into your world with the Litematica mod. The file stands the arch up as a wall, as many blocks thick as the depth you set.