I was trying to follow this tutorial made in Blender 2.71.x but I haven't figured out how it can be done in 2.93.x yet. He pulls out the self intersecting geometry but when I try and do it, it says no intersections found.
His example:
My example keeps saing no intersections found.
The video tutorial / section I'm trying to follow is. @1:16 https://youtu.be/-rwvxusuJXU?t=81