Maximum surface slope limits the toolpaths to portions of surfaces with a slope less than that angle. This is a good way to limit milling to the “flatter” portions of your model. This attribute applies to most finishing types of toolpaths (e.g., Parallel, Radial, etc.). The figure below shows an example of limiting X parallel toolpaths to the bottom of the mold by setting Maximum slope angle to 45 degrees. Note that the toolpaths do not climb up the steep walls.
See also Minimum surface slope.