How to use the dome generator
- Enter the diameter of the dome's base. The dome will be half that tall (rounded).
- Choose a shell thickness. 1 is enough for a roof; 2 gives a sturdier look and hides lighting blocks.
- Step through the layers with the slider or the ◀ ▶ buttons. Layer 1 is the base ring, the widest one. Each layer above gets smaller.
- Keep "Show layer below" switched on. The pale blocks show the previous ring, so you can line up each new layer on top.
Using domes as roofs
To roof a round tower, make the dome diameter equal to the tower's outer diameter. The first layer of the dome then sits directly on top of the walls. For an overhanging roof, add 2 to the diameter. Domes also make great observatories (use glass for the upper layers), igloos, greenhouses and underwater bases.
Why the top layers look flat
Near the top of a dome the curve is almost horizontal, so several blocks sit in the same layer and the top looks like a flat disc. That is correct: it is how a blocky hemisphere must look. If you want a pointier top, finish with a small sphere or a single block "cap".
How the dome is calculated
The dome is the upper half of a sphere. Each block is tested with x² + y² + z² ≤ r². For a hollow dome, a block is kept only if one of its six neighbours (up, down, north, south, east, west) is outside the sphere, which guarantees a shell with no holes. The counts per layer and in total are exact.
Frequently asked questions
How do you make a dome in Minecraft?
A dome is the top half of a sphere. Enter the base diameter, build the widest ring first (layer 1), then build each smaller ring one block higher, following the template layer by layer.
How tall is a dome?
About half of its diameter. A 21-block dome is 11 layers tall; a 20-block dome is 10.
How do I put a dome on a round tower?
Use the same diameter as the tower's outer wall so the first dome layer sits right on top of it. Add 2 to the diameter for an overhanging roof.
Why is the top of my dome flat?
At the top of a hemisphere the curve is almost horizontal, so the last layer is a small flat disc. That is correct for a blocky dome.