THE GEOMETRY FIELD JOURNAL
Onion Atlas
Find the edge. Reveal what lies beneath.
Peel every point cloud, one boundary at a time.
Imagine stretching a rubber band around all remaining points. Tap only the corners it touches, in order around the edge, then Peel boundary. Interior points wait for a later layer. Either direction and any starting point work.
What makes a boundary convex?
A convex boundary never caves inward. Every other remaining point lies on the same interior side of each edge. A point that is interior now may become an extreme corner after the outer layer is removed. Select the final one or two points in either order to finish.