Circle and Sphere Generator
Set the diameters and the generator lays out the shape block by block, then counts how many blocks the whole thing takes.
How we calculate
Every cell is tested against the ellipse equation: take its distance from the centre along each axis, divide by the matching radius, square it and add the terms up. The cell belongs to the shape when that sum stays at or below one. A sphere uses three terms instead of two — nothing else changes.
The parity of the diameter decides where the centre sits. An odd diameter puts the centre on a block, an even one puts it on the seam between blocks, so every cell coordinate shifts by half a block. Without that shift every even-sized shape comes out lopsided by one row.
The outline has no formula of its own — it is derived from the filled shape: a block stays in the outline if at least one of its axis neighbours already falls outside. A thick wall works differently: a smaller copy of the shape, shrunk by the wall thickness, is subtracted from the whole.
Sources
checked 18 August 2026
Questions and answers
Why does an even-diameter circle look different from an odd one?
An odd diameter gives you a centre block; an even one puts the centre on a seam and makes the shape symmetric about it. They are genuinely different shapes, not a generator bug.
How many blocks does a sphere take?
The generator counts them for you and shows the total under the layout, plus the count in every horizontal layer for spheres.
What is the difference between a thin and a thick outline?
Thin leaves exactly one layer of blocks around the edge. Thick subtracts a shrunken copy of the shape, so the wall comes out at the thickness you asked for and holds up at large diameters.
Can I build ovals rather than just circles?
Yes. Width, depth and height are set separately — equal values give a circle or sphere, different ones an oval or ellipsoid.
Unofficial tool. Not affiliated with the developers or publishers of Minecraft.