We present an algorithm for local surface smoothing in a defined Volume of Interest ("VOI") cropped from three-dimensional ("3D") volume data, such as lung computer tomography ("CT") data. Because the VOI is generally a smooth and piecewise linear surface, the inclusion of one or more bumps may suggest an abnormality. In lung CT data, for example, such bumps can be nodules that are grown from the chest wall. The nodules may represent a possibility of lung cancer. Through surface smoothing, potential pathologies are separated from the surrounding anatomical structures. For example, nodules may be segmented from the chest wall. The separated pathologies can be analyzed as diagnostic evidence.