User Guide

Hinting
579
Interpolate or Not
As you already know all points that were not positioned by commands
(untouched points) are interpolated automatically by the final
interpolation command. Final interpolation sets the position of any
untouched point proportionally to the closest untouched points. But
sometimes you may want to control the interpolation process and directly
set the base points of the interpolation. Usually this happens when a point
is geometrically between two touched points that belong to different
contours:
The only way to keep point 10 between points 31 and 34 is to set an
interpolation command in the vertical direction. It’s a good idea to
interpolate the same point in the horizontal direction too: