Abstract|This paper proposes a new method for cross-sectional segmentation based on use of the electric lines of force in an associated electrostatic problem and applies it to determination of cuto¬ in a circular waveguide using transverse resonance as the criterion. The technique has potential application in a wider variety of problems than the simple example chosen to illustrate it. Its use eliminates certain fundamental limitations inherent in some other proposals for cross-sectional segmentation that have been used in earlier numerical solutions.