The Start point(s) attribute controls the initial points for Z-level finish toolpaths. Note that it only works for toolpaths that are closed loops. Start point(s) can either be a single point or a curve made from a connected line. The closest point on the toolpath loop relative to the start point is found and that point is used as the starting point for the loop.
In this figure a spherical surface feature is viewed from the top.
The blue start point controls the location of the start of each toolpath.
See also 3D leads/step tab for information on transitions between toolpaths.