If you need a full 3D sphere preview, Plotz or a block-shape generator is probably closer to that use case.
For 2D circle layers, though, I use this kind of workflow:
1. choose the radius or diameter
2. generate the flat circle outline
3. build the widest layer first
4. reduce the radius layer by layer for domes or ball-like builds
This tool is useful for the 2D circle / ellipse layer part:
globalplay.games/tools/minecraft-circle-generatorIt does not replace a full 3D sphere generator, but it works well when you want clean layer-by-layer circle templates for Minecraft builds.
