Con trỏ 3D Blender (Blender 3D Cursor)

The 3D cursor in Blender is the red/white/black thing where new objects appear.

You'll need to print 16 sections of the circle, 8 in white and 8 in red. You'll then need to superglue them together. Because there can be slight imperfections in the print, I've included a file for a guide you can use to align the parts as you glue them together.

Before gluing the red/white circle completely closed, make sure you have it where you want on the black axes. Alternatively, you can glue the circle closed, align it, then glue the black z axis parts to lock it in place.

Files are in STL.