Abstract 
The paper presents a new interactive technique for correcting CAD/CAM data containing errors. An algorithm is described that can be used to correct surface data containing undesirable discontinuities ("gaps"/ "holes", and "overlaps") and intersections among surface patches. Such surface problems commonly arise in the aircraft, automobile, and ship industry and make later processing of the data difficult, if not impossible. The new method provides a tool to correct wrong data requiring minimal user interaction. The imput for the scheme can be a set of parametrically defined surfaces (e.i., Bezier, Bspline, or NURBS surfaces) or a set of triangles (or quadrilaterals) discretizing the original geometry. The output is a set of G0 or G1 (tangent plane)continuous, bicubic Bsplines surfaces approximating the given data. Each of these Bspline surfaces is constructed using just four userspecified boundary curves.
