Generally when available in the tool settings window, the tolerance setting helps you control the precision for arc and curve shapes. Larger tolerances result in more rough approximations of curved boundaries and smaller tolerances result in more smooth curved boundaries

The tolerance value is the maximum distance (in master units) between any point on a curved boundary and each of the line segments which approximate the curve. If the tolerance value is decreased, the number of approximating line segments which compose the curve increases, resulting in a finer quality, smoother curve boundary. If the tolerance value increases, the number of approximating line segments which compose the curve is reduced, resulting in a more coarse curve boundary.