Abstract: During the process of data acquisition in reverse engineering, the measuring data close to the boundary edges, under the influence of various factors, are sometimes missing. A practical algorithm for boundary surface straight fitting with incomplete point cloud is presented. The base surface is constructed automatically according to its boundary type. The points are projected to the base surface to get the parameters and meanwhile the weakness of each control point is calculated by using a new criterion. The weakly defined control points are constrained and discrete boundary constraints are included during the surface fitting process. The fitting surface is close to the point cloud while preserving good quality of its own. Furthermore, it satisfies approximate G1 continuity with adjacent surfaces. Practical application shows that the proposed algorithm is valid and valuable.

Key words: Boundary surface, Point cloud missing, Reverse engineering, Surface fitting, Weakly defined control point