Using an adaptive segment technique, a topological complex 3D surface can be developed into its corresponding 2D pattern. Firstly, triangular facet model is used to present a complex surface, and its quasi-rulings are computed. Secondly, the 3D surface is adaptively segmented based on its quasi-ruling. Finally, each segment is flatted into 2D pattern. This development algorithm can be directly used to computer aided design or texture mapping. It can be also applied to post-process in practical industrial modeling.