Abstract: Quality of the surface model reconstructed from cross sections is usually not good enough for application. A virtual measuring methodology based on composite triangular Bézier patches is proposed to solve this problem. First the local surface with bad quality is extracted. Then discrete points inside the local surface region are fitted with B-spline surface to form a fair shape. Then the tentative surface is resampled to obtain the refined triangular model. Some examples are shown to demonstrate the feasibility of the algorithm in improving the quality of reconstructed organ model. This methodology can also be applied to improve the quality of local surface form in reverse engineering of mechanical parts.