Create a toolpath that spirals out from the center of the contour. Spiral toolpaths are most efficient for round or near round design elements which allow the contour to be a single continuous spiral and eliminate the need for tool lifts. Objects that are not round require the tool to lift every time it encounters an edge creating more lifts than a normal Island Fill or Hatch Fill.
The images below illustrate a spiral fill toolpath for a circular contour and a square contour.
