Minecraft Sphere & Dome Generator

Building a sphere or dome by hand

A sphere is a stack of circles that shrink toward the poles. The hard part is not the maths, it is keeping forty layers lined up without a reference point.

1. 1

   Mark the centre column first

   Every layer is centred on the same column. Put a marker block at the centre of the base (or the four centre blocks for an even width) and run a temporary pillar straight up. Each layer is then built around the pillar rather than measured from the last one, so an error cannot carry upward.

2. 2

   Build from the widest layer outward

   For a sphere, start at the equator: it is the only layer you can lay directly on the ground or on scaffolding at full width. Work up and down from there. A dome already starts at its widest layer, so its base goes down first.

3. 3

   Use the faded layer below

   With the layer below shown faded, you can see exactly which blocks overhang the previous ring and which sit on top of it. Overhanging blocks need something to be placed against — place them from inside, or put a temporary block underneath and break it after.

4. 4

   Odd widths have a centre block, even widths do not

   Every layer of an odd sphere, including the flat cap on top, is centred on one block, so there is a single block dead centre for a beacon, a light or a spawner. An even sphere is centred on the corner between four blocks, which suits walls and doorways but gives nothing to align a single block to. WorldEdit can only build the odd kind.

5. 5

   Hollow counts are what you actually place

   A filled 31-wide sphere is 15,515 blocks; the hollow one is 2,382. Hollow shells here are face-connected, so there are no diagonal gaps for water, light or mobs to get through — you can glass it and it will hold.