逆向工程為一種由實物模型重建CAD模型的技術，已廣泛應用於工業界。由於產品造型變化極大，逆向重建手法繁瑣，同樣的產品往往會因為各人經驗多寡而使得重建結果不一致，影響到重建的品質及效率。本研究針對逆向重建中最困難的部份之一－曲面連續性問題，深入探討連續性理論及發展曲面間平滑且連續接合的技術，並開發逆向工程中網格、曲線及曲面等關鍵技術，協助曲面模型重建技術的提升。進一步將產品造型依照幾何特性歸納整理，分類為簡易造型、複雜造型及連續造型，配合上述逆向技術演算法開發，提出此三種造型的建構流程及範例說明，使逆向重建手法程序化，提升模型重建品質及效率。最後，整合本研究發展的各項技術，發展出曲面模型自動化重建技術，自動重建出具有連續性特徵的完整CAD模型，實現造型產品的自動化快速逆向重建。 本研究所發展的各項技術具體說明如下：網格特徵分離技術，以幾何特徵分離出獨立的網格區塊；從網格上擷取出順序性的點資料，發展多種曲線嵌合技術；發展曲面連續性縫合理論，使得曲面接合邊界能達到G0、G1或G2連續；將連續性理論與曲面嵌合理論結合，提出曲面連續性嵌合演算法；結合上述各項技術，發展出曲面模型自動化重建技術，快速重建出完整的CAD模型。 Reverse engineering, a technique to reconstruct the CAD model from the three-dimensional data of an object, has been widely used in industry. Traditional reverse engineering process mainly relies on manual operation to rebuild the CAD model. Owing to the complexity and variability of the shape of industrial products, the CAD model reconstructed generally varies in terms of the experience and skills of the operators. This study focuses on the investigation of the most difficult problem in reverse engineering－surface continuity. The issues related to the theory, technique and application of surface continuity in reverse engineering are investigated, and the key techniques of processing triangular meshes, curves and surfaces for successful surface reconstruction are developed. The products are typically classified into the following three types in accordance with their shape: simple shape, complicated shape and continuous shape. Different surface reconstruction methods for the above three types of shapes are developed to enhance the quality of the surface model and to promote the efficiency of the surface reconstruction process. Moreover, several examples are presented to illustrate the feasibility of the proposed methods. In addition, an automatic surface reconstruction process is presented to rebuild a model of B-spline surfaces from a huge number of triangular meshes, which can change traditional reverse engineering process tremendously as the entire process is almost done automatically. The techniques developed in this study can specifically be classified into the following five topics: data segmentation for the partition of the triangular meshes, five kinds of curve fitting algorithms to fit points into curves, surface stitching technique for G0, G1 and G2 continuity between two surfaces, surface fitting algorithm of random points with four boundary curves and continuity information from adjacent surfaces, and a novel method for automatic surface reconstruction from a huge number of triangular meshes.
