How to build a sphere in Minecraft
- Pick a diameter. Odd sizes have a single centre block, which makes lining up easier.
- Mark the centre on the ground and build layer 1, the bottom, from the picture.
- Go up one block and build the next layer. The faint blocks show the layer you just placed.
- Keep going to the top. For a dome, layer 1 is the widest ring and you work upwards from there.
Hollow or solid?
Hollow keeps only the outer shell, one block thick with no gaps, so it's what you want for builds you can walk inside, like a glass dome or a planet base. Solid fills the whole thing, which uses far more blocks: a 15 block solid sphere needs more than three times as many as a hollow one.
Building something round?
Flat circles and ovals for floors, towers and ponds are in the circle generator. Linking your base to the Nether? Use the nether portal calculator.